Leetcode-Solutions

Collection of LeetCode questions to ace the coding interview!!

Array

0347-top-k-frequent-elements
1137-height-checker

Sorting

0347-top-k-frequent-elements
1137-height-checker

Counting Sort

0347-top-k-frequent-elements
1137-height-checker

Tree

1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree

Depth-First Search

1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree

Binary Search Tree

1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree

Binary Tree

1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree

Hash Table

0347-top-k-frequent-elements

Divide and Conquer

0347-top-k-frequent-elements
1285-balance-a-binary-search-tree

Heap (Priority Queue)

0347-top-k-frequent-elements

Bucket Sort

0347-top-k-frequent-elements

Quickselect

0347-top-k-frequent-elements

Greedy

1285-balance-a-binary-search-tree

LeetCode Topics

Depth-First Search

0099-recover-binary-search-tree
0101-symmetric-tree
0110-balanced-binary-tree
0133-clone-graph
0145-binary-tree-postorder-traversal
0210-course-schedule-ii
0211-design-add-and-search-words-data-structure
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0257-binary-tree-paths
0297-serialize-and-deserialize-binary-tree
0386-lexicographical-numbers
0515-find-largest-value-in-each-tree-row
0530-minimum-absolute-difference-in-bst
0572-subtree-of-another-tree
0617-merge-two-binary-trees
0684-redundant-connection
0733-flood-fill
0776-n-ary-tree-postorder-traversal
0820-find-eventual-safe-states
0854-making-a-large-island
0984-most-stones-removed-with-same-row-or-column
0988-flip-equivalent-binary-trees
0999-regions-cut-by-slashes
1093-recover-a-tree-from-preorder-traversal
1218-lowest-common-ancestor-of-deepest-leaves
1350-remove-sub-folders-from-the-filesystem
1387-find-elements-in-a-contaminated-binary-tree
1396-count-servers-that-communicate
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1484-linked-list-in-binary-tree
1544-count-good-nodes-in-binary-tree
1558-course-schedule-iv
1653-number-of-good-leaf-nodes-pairs
2035-count-sub-islands
2201-valid-arrangement-of-pairs
2217-step-by-step-directions-from-a-binary-tree-node-to-another
2246-maximum-employees-to-be-invited-to-a-meeting
2400-minimum-score-after-removals-on-a-tree
2438-find-closest-node-to-given-two-nodes
2493-reverse-odd-levels-of-binary-tree
2564-most-profitable-path-in-a-tree
2677-cousins-in-binary-tree-ii
2764-maximum-number-of-fish-in-a-grid
2793-count-the-number-of-complete-components
3058-maximum-number-of-k-divisible-components
3633-maximize-the-number-of-target-nodes-after-connecting-trees-i
3645-maximize-the-number-of-target-nodes-after-connecting-trees-ii

Breadth-First Search

0101-symmetric-tree
0102-binary-tree-level-order-traversal
0127-word-ladder
0133-clone-graph
0210-course-schedule-ii
0226-invert-binary-tree
0297-serialize-and-deserialize-binary-tree
0322-coin-change
0407-trapping-rain-water-ii
0515-find-largest-value-in-each-tree-row
0530-minimum-absolute-difference-in-bst
0617-merge-two-binary-trees
0684-redundant-connection
0733-flood-fill
0787-sliding-puzzle
0820-find-eventual-safe-states
0854-making-a-large-island
0945-snakes-and-ladders
0999-regions-cut-by-slashes
1218-lowest-common-ancestor-of-deepest-leaves
1387-find-elements-in-a-contaminated-binary-tree
1396-count-servers-that-communicate
1424-maximum-candies-you-can-get-from-boxes
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1484-linked-list-in-binary-tree
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1544-count-good-nodes-in-binary-tree
1558-course-schedule-iv
1731-even-odd-tree
1876-map-of-highest-peak
2035-count-sub-islands
2171-second-minimum-time-to-reach-destination
2375-minimum-obstacle-removal-to-reach-corner
2493-reverse-odd-levels-of-binary-tree
2558-minimum-number-of-operations-to-sort-a-binary-tree-by-level
2564-most-profitable-path-in-a-tree
2583-divide-nodes-into-the-maximum-number-of-groups
2588-maximum-number-of-points-from-grid-queries
2646-kth-largest-sum-in-a-binary-tree
2677-cousins-in-binary-tree-ii
2711-minimum-time-to-visit-a-cell-in-a-grid
2764-maximum-number-of-fish-in-a-grid
2793-count-the-number-of-complete-components
3517-shortest-distance-after-road-addition-queries-i
3633-maximize-the-number-of-target-nodes-after-connecting-trees-i
3645-maximize-the-number-of-target-nodes-after-connecting-trees-ii

Graph

0133-clone-graph
0210-course-schedule-ii
0684-redundant-connection
0820-find-eventual-safe-states
0984-most-stones-removed-with-same-row-or-column
1325-path-with-maximum-probability
1424-maximum-candies-you-can-get-from-boxes
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1456-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1558-course-schedule-iv
1701-remove-max-number-of-edges-to-keep-graph-fully-traversable
1738-maximal-network-rank
2090-number-of-ways-to-arrive-at-destination
2171-second-minimum-time-to-reach-destination
2201-valid-arrangement-of-pairs
2220-find-all-possible-recipes-from-given-supplies
2246-maximum-employees-to-be-invited-to-a-meeting
2375-minimum-obstacle-removal-to-reach-corner
2438-find-closest-node-to-given-two-nodes
2564-most-profitable-path-in-a-tree
2583-divide-nodes-into-the-maximum-number-of-groups
2711-minimum-time-to-visit-a-cell-in-a-grid
2793-count-the-number-of-complete-components
2803-modify-graph-edge-weights
3189-find-champion-ii
3235-minimum-cost-to-convert-string-i
3348-minimum-cost-walk-in-weighted-graph
3517-shortest-distance-after-road-addition-queries-i
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii

Topological Sort

0210-course-schedule-ii
0820-find-eventual-safe-states
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1558-course-schedule-iv
2090-number-of-ways-to-arrive-at-destination
2220-find-all-possible-recipes-from-given-supplies
2246-maximum-employees-to-be-invited-to-a-meeting

Union Find

0128-longest-consecutive-sequence
0684-redundant-connection
0854-making-a-large-island
0984-most-stones-removed-with-same-row-or-column
0999-regions-cut-by-slashes
1058-lexicographically-smallest-equivalent-string
1396-count-servers-that-communicate
1701-remove-max-number-of-edges-to-keep-graph-fully-traversable
2035-count-sub-islands
2583-divide-nodes-into-the-maximum-number-of-groups
2588-maximum-number-of-points-from-grid-queries
2764-maximum-number-of-fish-in-a-grid
2793-count-the-number-of-complete-components
3219-make-lexicographically-smallest-array-by-swapping-elements
3348-minimum-cost-walk-in-weighted-graph

Array

0001-two-sum
0004-median-of-two-sorted-arrays
0011-container-with-most-water
0027-remove-element
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0036-valid-sudoku
0039-combination-sum
0040-combination-sum-ii
0041-first-missing-positive
0048-rotate-image
0053-maximum-subarray
0054-spiral-matrix
0055-jump-game
0056-merge-intervals
0057-insert-interval
0064-minimum-path-sum
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0075-sort-colors
0084-largest-rectangle-in-histogram
0088-merge-sorted-array
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0108-convert-sorted-array-to-binary-search-tree
0118-pascals-triangle
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0128-longest-consecutive-sequence
0135-candy
0139-word-break
0152-maximum-product-subarray
0153-find-minimum-in-rotated-sorted-array
0169-majority-element
0179-largest-number
0198-house-robber
0204-count-primes
0209-minimum-size-subarray-sum
0212-word-search-ii
0213-house-robber-ii
0215-kth-largest-element-in-an-array
0229-majority-element-ii
0239-sliding-window-maximum
0240-search-a-2d-matrix-ii
0274-h-index
0303-range-sum-query-immutable
0322-coin-change
0347-top-k-frequent-elements
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0368-largest-divisible-subset
0380-insert-delete-getrandom-o1
0407-trapping-rain-water-ii
0416-partition-equal-subset-sum
0448-find-all-numbers-disappeared-in-an-array
0455-assign-cookies
0475-heaters
0494-target-sum
0498-diagonal-traverse
0539-minimum-time-difference
0594-longest-harmonious-subsequence
0621-task-scheduler
0624-maximum-distance-in-arrays
0632-smallest-range-covering-elements-from-k-lists
0679-24-game
0719-find-k-th-smallest-pair-distance
0729-my-calendar-i
0731-my-calendar-ii
0733-flood-fill
0780-max-chunks-to-make-sorted
0787-sliding-puzzle
0797-rabbits-in-forest
0816-design-hashset
0854-making-a-large-island
0859-design-circular-deque
0870-magic-squares-in-grid
0890-lemonade-change
0892-shortest-subarray-with-sum-at-least-k
0905-length-of-longest-fibonacci-subsequence
0906-walking-robot-simulation
0907-koko-eating-bananas
0912-random-pick-with-weight
0921-spiral-matrix-iii
0934-bitwise-ors-of-subarrays
0940-fruit-into-baskets
0945-snakes-and-ladders
0948-sort-an-array
0952-word-subsets
0965-unique-email-addresses
0999-regions-cut-by-slashes
1002-maximum-width-ramp
1014-k-closest-points-to-origin
1025-minimum-cost-for-tickets
1046-max-consecutive-ones-iii
1049-minimum-domino-rotations-for-equal-row
1147-flip-columns-for-maximum-number-of-equal-rows
1196-filling-bookcase-shelves
1227-number-of-equivalent-domino-pairs
1240-stone-game-ii
1256-rank-transform-of-an-array
1293-three-consecutive-odds
1325-path-with-maximum-probability
1333-sort-the-jumbled-numbers
1335-maximum-candies-allocated-to-k-children
1350-remove-sub-folders-from-the-filesystem
1396-count-servers-that-communicate
1402-count-square-submatrices-with-all-ones
1421-find-numbers-with-even-number-of-digits
1424-maximum-candies-you-can-get-from-boxes
1426-find-n-unique-integers-sum-up-to-zero
1435-xor-queries-of-a-subarray
1468-check-if-n-and-its-double-exist
1477-product-of-the-last-k-numbers
1478-maximum-number-of-events-that-can-be-attended
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1487-cinema-seat-allocation
1496-lucky-numbers-in-a-matrix
1497-design-a-stack-with-increment-operation
1510-find-lucky-integer-in-an-array
1511-count-number-of-teams
1524-string-matching-in-an-array
1556-make-two-arrays-equal-by-reversing-subarrays
1570-final-prices-with-a-special-discount-in-a-shop
1586-longest-subarray-of-1s-after-deleting-one-element
1615-range-sum-of-sorted-subarray-sums
1616-minimum-difference-between-largest-and-smallest-value-in-three-moves
1620-check-if-array-pairs-are-divisible-by-k
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1628-count-submatrices-with-all-ones
1631-number-of-sub-arrays-with-odd-sum
1656-count-good-triplets
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1694-make-sum-divisible-by-p
1700-minimum-time-to-make-rope-colorful
1711-find-valid-matrix-given-row-and-column-sums
1720-crawler-log-folder
1741-sort-array-by-increasing-frequency
1766-minimum-number-of-removals-to-make-mountain-array
1786-count-the-number-of-consistent-strings
1803-average-waiting-time
1813-maximum-erasure-value
1819-construct-the-lexicographically-largest-valid-sequence
1849-maximum-absolute-sum-of-any-subarray
1851-maximum-number-of-events-that-can-be-attended-ii
1876-map-of-highest-peak
1878-check-if-array-is-sorted-and-rotated
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1901-equal-sum-arrays-with-minimum-number-of-operations
1917-maximum-average-pass-ratio
1923-sentence-similarity-iii
1940-maximum-xor-for-each-query
1951-find-the-winner-of-the-circular-game
1972-rotating-the-box
1993-sum-of-all-subset-xor-totals
1995-finding-pairs-with-a-certain-sum
2006-find-the-student-that-will-replace-the-chalk
2035-count-sub-islands
2048-build-array-from-permutation
2054-the-number-of-the-smallest-unoccupied-chair
2067-maximum-number-of-points-with-cost
2079-delete-duplicate-folders-in-system
2089-maximum-matrix-sum
2107-find-unique-binary-string
2132-convert-1d-array-into-2d-array
2144-maximum-difference-between-increasing-elements
2145-grid-game
2150-kth-smallest-product-of-two-sorted-arrays
2155-find-missing-observations
2163-kth-distinct-string-in-an-array
2170-count-number-of-maximum-bitwise-or-subsets
2179-most-beautiful-item-for-each-query
2180-maximum-number-of-tasks-you-can-assign
2188-minimized-maximum-of-products-distributed-to-any-store
2215-finding-3-digit-even-numbers
2220-find-all-possible-recipes-from-given-supplies
2229-maximum-fruits-harvested-after-at-most-k-steps
2232-adding-spaces-to-a-string
2237-longest-palindrome-by-concatenating-two-letter-words
2249-count-the-hidden-sequences
2255-minimum-swaps-to-group-all-1s-together-ii
2262-solving-questions-with-brainpower
2265-partition-array-according-to-given-pivot
2267-minimum-difference-in-sums-after-removal-of-elements
2277-count-equal-and-divisible-pairs-in-an-array
2280-count-good-triplets-in-an-array
2306-create-binary-tree-from-descriptions
2308-divide-array-into-equal-pairs
2316-count-hills-and-valleys-in-an-array
2343-count-unguarded-cells-in-the-grid
2356-largest-combination-with-bitwise-and-greater-than-zero
2358-number-of-ways-to-split-array
2375-minimum-obstacle-removal-to-reach-corner
2387-partition-array-such-that-maximum-difference-is-k
2394-count-subarrays-with-score-less-than-k
2400-minimum-score-after-removals-on-a-tree
2411-spiral-matrix-iv
2432-number-of-zero-filled-subarrays
2448-count-number-of-bad-pairs
2465-shifting-letters-ii
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2479-meeting-rooms-iii
2488-divide-intervals-into-minimum-number-of-groups
2494-sum-of-prefix-scores-of-strings
2497-maximum-matching-of-players-with-trainers
2498-smallest-subarrays-with-maximum-bitwise-or
2502-sort-the-people
2503-longest-subarray-with-maximum-bitwise-and
2527-count-subarrays-with-fixed-bounds
2529-range-product-queries-of-powers
2533-bitwise-xor-of-all-pairings
2551-apply-operations-to-an-array
2552-maximum-sum-of-distinct-subarrays-with-length-k
2554-minimum-total-distance-traveled
2564-most-profitable-path-in-a-tree
2588-maximum-number-of-points-from-grid-queries
2614-maximum-count-of-positive-integer-and-negative-integer
2616-maximal-score-after-applying-k-operations
2626-count-the-number-of-good-subarrays
2640-maximum-number-of-integers-to-choose-from-a-range-i
2665-minimum-time-to-repair-cars
2681-put-marbles-in-bags
2685-first-completely-painted-row-or-column
2689-rearranging-fruits
2690-house-robber-iv
2691-count-vowel-strings-in-ranges
2692-take-gifts-from-the-richest-pile
2695-find-score-of-an-array-after-marking-all-elements
2699-count-the-number-of-fair-pairs
2707-merge-two-2d-arrays-by-summing-values
2711-minimum-time-to-visit-a-cell-in-a-grid
2716-prime-subtraction-operation
2720-minimize-the-maximum-difference-of-pairs
2727-number-of-senior-citizens
2755-extra-characters-in-a-string
2764-maximum-number-of-fish-in-a-grid
2766-find-the-prefix-common-array-of-two-arrays
2792-neighboring-bitwise-xor
2794-maximum-number-of-moves-in-a-grid
2846-robot-collisions
2856-count-complete-subarrays-in-an-array
2888-minimum-index-of-a-valid-split
2915-count-of-interesting-subarrays
3001-apply-operations-to-maximize-score
3142-longest-unequal-adjacent-groups-subsequence-ii
3143-longest-unequal-adjacent-groups-subsequence-i
3152-maximum-value-of-an-ordered-triplet-ii
3154-maximum-value-of-an-ordered-triplet-i
3171-minimum-equal-sum-of-two-arrays-after-replacing-zeros
3181-find-building-where-alice-and-bob-can-meet
3194-find-words-containing-character
3213-count-subarrays-where-max-element-appears-at-least-k-times
3219-make-lexicographically-smallest-array-by-swapping-elements
3227-find-missing-and-repeated-values
3235-minimum-cost-to-convert-string-i
3251-maximum-area-of-longest-diagonal-rectangle
3277-find-the-number-of-ways-to-place-people-ii
3278-find-the-number-of-ways-to-place-people-i
3291-find-if-array-can-be-sorted
3309-count-prefix-and-suffix-pairs-i
3321-type-of-triangle
3329-find-the-length-of-the-longest-common-prefix
3332-minimum-operations-to-exceed-threshold-value-ii
3348-minimum-cost-walk-in-weighted-graph
3372-longest-strictly-increasing-or-strictly-decreasing-subarray
3427-special-array-ii
3429-special-array-i
3430-count-days-without-meetings
3434-find-the-number-of-distinct-colors-among-the-balls
3459-find-the-minimum-area-to-cover-all-ones-ii
3461-find-the-minimum-area-to-cover-all-ones-i
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3483-alternating-groups-ii
3490-find-the-maximum-length-of-valid-subsequence-i
3491-find-the-maximum-length-of-valid-subsequence-ii
3501-delete-nodes-from-linked-list-present-in-array
3517-shortest-distance-after-road-addition-queries-i
3522-find-the-power-of-k-size-subarrays-i
3555-final-array-state-after-k-multiplication-operations-i
3621-minimum-operations-to-make-array-values-equal-to-k
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii
3639-zero-array-transformation-i
3643-zero-array-transformation-ii
3647-zero-array-transformation-iii
3648-find-the-maximum-number-of-fruits-collected
3656-minimum-number-of-operations-to-make-elements-in-array-distinct
3657-check-if-grid-can-be-cut-into-sections
3685-count-subarrays-of-length-three-with-a-condition
3733-length-of-longest-v-shaped-diagonal-segment
3741-reschedule-meetings-for-maximum-free-time-ii
3743-reschedule-meetings-for-maximum-free-time-i
3744-minimum-operations-to-make-array-elements-zero
3748-sort-matrix-by-diagonals
3788-maximum-unique-subarray-sum-after-deletion
3789-maximize-subarrays-after-removing-one-conflicting-pair
3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii

Hash Table

0001-two-sum
0012-integer-to-roman
0017-letter-combinations-of-a-phone-number
0036-valid-sudoku
0041-first-missing-positive
0073-set-matrix-zeroes
0076-minimum-window-substring
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0127-word-ladder
0128-longest-consecutive-sequence
0133-clone-graph
0139-word-break
0141-linked-list-cycle
0146-lru-cache
0160-intersection-of-two-linked-lists
0169-majority-element
0202-happy-number
0205-isomorphic-strings
0208-implement-trie-prefix-tree
0229-majority-element-ii
0264-ugly-number-ii
0299-bulls-and-cows
0347-top-k-frequent-elements
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0380-insert-delete-getrandom-o1
0424-longest-repeating-character-replacement
0432-all-oone-data-structure
0448-find-all-numbers-disappeared-in-an-array
0594-longest-harmonious-subsequence
0621-task-scheduler
0632-smallest-range-covering-elements-from-k-lists
0726-number-of-atoms
0768-partition-labels
0797-rabbits-in-forest
0816-design-hashset
0870-magic-squares-in-grid
0900-reordered-power-of-2
0905-length-of-longest-fibonacci-subsequence
0906-walking-robot-simulation
0920-uncommon-words-from-two-sentences
0940-fruit-into-baskets
0952-word-subsets
0965-unique-email-addresses
0984-most-stones-removed-with-same-row-or-column
0999-regions-cut-by-slashes
1023-time-based-key-value-store
1147-flip-columns-for-maximum-number-of-equal-rows
1160-letter-tile-possibilities
1218-lowest-common-ancestor-of-deepest-leaves
1227-number-of-equivalent-domino-pairs
1256-rank-transform-of-an-array
1387-find-elements-in-a-contaminated-binary-tree
1460-number-of-substrings-containing-all-three-characters
1468-check-if-n-and-its-double-exist
1473-find-the-longest-substring-containing-vowels-in-even-counts
1487-cinema-seat-allocation
1500-count-largest-group
1502-construct-k-palindrome-strings
1510-find-lucky-integer-in-an-array
1556-make-two-arrays-equal-by-reversing-subarrays
1620-check-if-array-pairs-are-divisible-by-k
1694-make-sum-divisible-by-p
1715-split-a-string-into-the-max-number-of-unique-substrings
1741-sort-array-by-increasing-frequency
1770-minimum-deletions-to-make-character-frequencies-unique
1786-count-the-number-of-consistent-strings
1813-maximum-erasure-value
1901-equal-sum-arrays-with-minimum-number-of-operations
1915-check-if-one-string-swap-can-make-strings-equal
1995-finding-pairs-with-a-certain-sum
2054-the-number-of-the-smallest-unoccupied-chair
2059-unique-length-3-palindromic-subsequences
2079-delete-duplicate-folders-in-system
2107-find-unique-binary-string
2163-kth-distinct-string-in-an-array
2215-finding-3-digit-even-numbers
2220-find-all-possible-recipes-from-given-supplies
2237-longest-palindrome-by-concatenating-two-letter-words
2300-construct-string-with-repeat-limit
2306-create-binary-tree-from-descriptions
2308-divide-array-into-equal-pairs
2356-largest-combination-with-bitwise-and-greater-than-zero
2434-design-a-number-container-system
2448-count-number-of-bad-pairs
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2479-meeting-rooms-iii
2502-sort-the-people
2520-using-a-robot-to-print-the-lexicographically-smallest-string
2552-maximum-sum-of-distinct-subarrays-with-length-k
2599-take-k-of-each-character-from-left-and-right
2626-count-the-number-of-good-subarrays
2640-maximum-number-of-integers-to-choose-from-a-range-i
2677-cousins-in-binary-tree-ii
2685-first-completely-painted-row-or-column
2689-rearranging-fruits
2695-find-score-of-an-array-after-marking-all-elements
2707-merge-two-2d-arrays-by-summing-values
2755-extra-characters-in-a-string
2766-find-the-prefix-common-array-of-two-arrays
2856-count-complete-subarrays-in-an-array
2888-minimum-index-of-a-valid-split
2915-count-of-interesting-subarrays
3227-find-missing-and-repeated-values
3276-minimum-number-of-pushes-to-type-word-ii
3329-find-the-length-of-the-longest-common-prefix
3360-minimum-deletions-to-make-string-k-special
3434-find-the-number-of-distinct-colors-among-the-balls
3445-lexicographically-minimum-string-after-removing-stars
3455-minimum-length-of-string-after-operations
3501-delete-nodes-from-linked-list-present-in-array
3548-find-the-count-of-good-integers
3569-count-of-substrings-containing-every-vowel-and-k-consonants-ii
3621-minimum-operations-to-make-array-values-equal-to-k
3630-total-characters-in-string-after-transformations-ii
3656-minimum-number-of-operations-to-make-elements-in-array-distinct
3753-maximum-difference-between-even-and-odd-frequency-i
3788-maximum-unique-subarray-sum-after-deletion

Matrix

0036-valid-sudoku
0048-rotate-image
0054-spiral-matrix
0064-minimum-path-sum
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0212-word-search-ii
0240-search-a-2d-matrix-ii
0407-trapping-rain-water-ii
0498-diagonal-traverse
0733-flood-fill
0787-sliding-puzzle
0854-making-a-large-island
0870-magic-squares-in-grid
0921-spiral-matrix-iii
0945-snakes-and-ladders
0999-regions-cut-by-slashes
1147-flip-columns-for-maximum-number-of-equal-rows
1396-count-servers-that-communicate
1402-count-square-submatrices-with-all-ones
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1496-lucky-numbers-in-a-matrix
1628-count-submatrices-with-all-ones
1711-find-valid-matrix-given-row-and-column-sums
1876-map-of-highest-peak
1972-rotating-the-box
2035-count-sub-islands
2089-maximum-matrix-sum
2132-convert-1d-array-into-2d-array
2145-grid-game
2343-count-unguarded-cells-in-the-grid
2375-minimum-obstacle-removal-to-reach-corner
2411-spiral-matrix-iv
2588-maximum-number-of-points-from-grid-queries
2685-first-completely-painted-row-or-column
2711-minimum-time-to-visit-a-cell-in-a-grid
2764-maximum-number-of-fish-in-a-grid
2794-maximum-number-of-moves-in-a-grid
3227-find-missing-and-repeated-values
3459-find-the-minimum-area-to-cover-all-ones-ii
3461-find-the-minimum-area-to-cover-all-ones-i
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii
3648-find-the-maximum-number-of-fruits-collected
3733-length-of-longest-v-shaped-diagonal-segment
3748-sort-matrix-by-diagonals

Two Pointers

0005-longest-palindromic-substring
0011-container-with-most-water
0019-remove-nth-node-from-end-of-list
0027-remove-element
0075-sort-colors
0086-partition-list
0088-merge-sorted-array
0141-linked-list-cycle
0143-reorder-list
0151-reverse-words-in-a-string
0160-intersection-of-two-linked-lists
0202-happy-number
0295-find-median-from-data-stream
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0455-assign-cookies
0475-heaters
0557-reverse-words-in-a-string-iii
0680-valid-palindrome-ii
0719-find-k-th-smallest-pair-distance
0768-partition-labels
0868-push-dominoes
0874-backspace-string-compare
0908-middle-of-the-linked-list
1468-check-if-n-and-its-double-exist
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
1615-range-sum-of-sorted-subarray-sums
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1923-sentence-similarity-iii
1972-rotating-the-box
2095-minimum-number-of-swaps-to-make-the-string-balanced
2232-adding-spaces-to-a-string
2265-partition-array-according-to-given-pivot
2414-move-pieces-to-obtain-a-string
2488-divide-intervals-into-minimum-number-of-groups
2497-maximum-matching-of-players-with-trainers
2551-apply-operations-to-an-array
2588-maximum-number-of-points-from-grid-queries
2699-count-the-number-of-fair-pairs
2707-merge-two-2d-arrays-by-summing-values
3195-separate-black-and-white-balls
3683-find-the-lexicographically-largest-string-from-the-box-i

Binary Search

0004-median-of-two-sorted-arrays
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0069-sqrtx
0074-search-a-2d-matrix
0153-find-minimum-in-rotated-sorted-array
0209-minimum-size-subarray-sum
0240-search-a-2d-matrix-ii
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0475-heaters
0719-find-k-th-smallest-pair-distance
0729-my-calendar-i
0731-my-calendar-ii
0892-shortest-subarray-with-sum-at-least-k
0907-koko-eating-bananas
0912-random-pick-with-weight
1023-time-based-key-value-store
1046-max-consecutive-ones-iii
1335-maximum-candies-allocated-to-k-children
1468-check-if-n-and-its-double-exist
1615-range-sum-of-sorted-subarray-sums
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1766-minimum-number-of-removals-to-make-mountain-array
1851-maximum-number-of-events-that-can-be-attended-ii
2006-find-the-student-that-will-replace-the-chalk
2150-kth-smallest-product-of-two-sorted-arrays
2179-most-beautiful-item-for-each-query
2180-maximum-number-of-tasks-you-can-assign
2188-minimized-maximum-of-products-distributed-to-any-store
2229-maximum-fruits-harvested-after-at-most-k-steps
2280-count-good-triplets-in-an-array
2394-count-subarrays-with-score-less-than-k
2498-smallest-subarrays-with-maximum-bitwise-or
2614-maximum-count-of-positive-integer-and-negative-integer
2640-maximum-number-of-integers-to-choose-from-a-range-i
2665-minimum-time-to-repair-cars
2690-house-robber-iv
2699-count-the-number-of-fair-pairs
2716-prime-subtraction-operation
2720-minimize-the-maximum-difference-of-pairs
3181-find-building-where-alice-and-bob-can-meet
3427-special-array-ii
3643-zero-array-transformation-ii
3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii

Sorting

0056-merge-intervals
0075-sort-colors
0088-merge-sorted-array
0169-majority-element
0179-largest-number
0215-kth-largest-element-in-an-array
0229-majority-element-ii
0274-h-index
0295-find-median-from-data-stream
0347-top-k-frequent-elements
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0368-largest-divisible-subset
0455-assign-cookies
0475-heaters
0539-minimum-time-difference
0594-longest-harmonious-subsequence
0621-task-scheduler
0632-smallest-range-covering-elements-from-k-lists
0719-find-k-th-smallest-pair-distance
0726-number-of-atoms
0780-max-chunks-to-make-sorted
0900-reordered-power-of-2
0948-sort-an-array
1014-k-closest-points-to-origin
1256-rank-transform-of-an-array
1333-sort-the-jumbled-numbers
1468-check-if-n-and-its-double-exist
1478-maximum-number-of-events-that-can-be-attended
1556-make-two-arrays-equal-by-reversing-subarrays
1615-range-sum-of-sorted-subarray-sums
1616-minimum-difference-between-largest-and-smallest-value-in-three-moves
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1741-sort-array-by-increasing-frequency
1770-minimum-deletions-to-make-character-frequencies-unique
1851-maximum-number-of-events-that-can-be-attended-ii
2179-most-beautiful-item-for-each-query
2180-maximum-number-of-tasks-you-can-assign
2215-finding-3-digit-even-numbers
2387-partition-array-such-that-maximum-difference-is-k
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2479-meeting-rooms-iii
2488-divide-intervals-into-minimum-number-of-groups
2497-maximum-matching-of-players-with-trainers
2502-sort-the-people
2554-minimum-total-distance-traveled
2588-maximum-number-of-points-from-grid-queries
2640-maximum-number-of-integers-to-choose-from-a-range-i
2646-kth-largest-sum-in-a-binary-tree
2681-put-marbles-in-bags
2689-rearranging-fruits
2695-find-score-of-an-array-after-marking-all-elements
2699-count-the-number-of-fair-pairs
2846-robot-collisions
2888-minimum-index-of-a-valid-split
3001-apply-operations-to-maximize-score
3219-make-lexicographically-smallest-array-by-swapping-elements
3276-minimum-number-of-pushes-to-type-word-ii
3277-find-the-number-of-ways-to-place-people-ii
3278-find-the-number-of-ways-to-place-people-i
3291-find-if-array-can-be-sorted
3321-type-of-triangle
3360-minimum-deletions-to-make-string-k-special
3430-count-days-without-meetings
3647-zero-array-transformation-iii
3657-check-if-grid-can-be-cut-into-sections
3748-sort-matrix-by-diagonals
3859-maximum-product-of-two-digits

Greedy

0011-container-with-most-water
0055-jump-game
0122-best-time-to-buy-and-sell-stock-ii
0135-candy
0179-largest-number
0316-remove-duplicate-letters
0402-remove-k-digits
0455-assign-cookies
0621-task-scheduler
0624-maximum-distance-in-arrays
0632-smallest-range-covering-elements-from-k-lists
0670-maximum-swap
0678-valid-parenthesis-string
0680-valid-palindrome-ii
0768-partition-labels
0780-max-chunks-to-make-sorted
0797-rabbits-in-forest
0890-lemonade-change
0957-minimum-add-to-make-parentheses-valid
1049-minimum-domino-rotations-for-equal-row
1304-longest-happy-string
1448-maximum-69-number
1478-maximum-number-of-events-that-can-be-attended
1487-cinema-seat-allocation
1502-construct-k-palindrome-strings
1529-max-difference-you-can-get-from-changing-an-integer
1616-minimum-difference-between-largest-and-smallest-value-in-three-moves
1700-minimum-time-to-make-rope-colorful
1711-find-valid-matrix-given-row-and-column-sums
1766-minimum-number-of-removals-to-make-mountain-array
1770-minimum-deletions-to-make-character-frequencies-unique
1818-maximum-score-from-removing-substrings
1901-equal-sum-arrays-with-minimum-number-of-operations
1917-maximum-average-pass-ratio
2089-maximum-matrix-sum
2095-minimum-number-of-swaps-to-make-the-string-balanced
2140-longest-subsequence-repeated-k-times
2180-maximum-number-of-tasks-you-can-assign
2221-check-if-a-parentheses-string-can-be-valid
2237-longest-palindrome-by-concatenating-two-letter-words
2300-construct-string-with-repeat-limit
2387-partition-array-such-that-maximum-difference-is-k
2395-longest-binary-subsequence-less-than-or-equal-to-k
2456-construct-smallest-number-from-di-string
2488-divide-intervals-into-minimum-number-of-groups
2497-maximum-matching-of-players-with-trainers
2509-minimize-xor
2520-using-a-robot-to-print-the-lexicographically-smallest-string
2616-maximal-score-after-applying-k-operations
2640-maximum-number-of-integers-to-choose-from-a-range-i
2681-put-marbles-in-bags
2689-rearranging-fruits
2704-maximum-difference-by-remapping-a-digit
2716-prime-subtraction-operation
2720-minimize-the-maximum-difference-of-pairs
3001-apply-operations-to-maximize-score
3143-longest-unequal-adjacent-groups-subsequence-i
3171-minimum-equal-sum-of-two-arrays-after-replacing-zeros
3195-separate-black-and-white-balls
3276-minimum-number-of-pushes-to-type-word-ii
3360-minimum-deletions-to-make-string-k-special
3445-lexicographically-minimum-string-after-removing-stars
3647-zero-array-transformation-iii
3741-reschedule-meetings-for-maximum-free-time-ii
3743-reschedule-meetings-for-maximum-free-time-i
3788-maximum-unique-subarray-sum-after-deletion

Math

0002-add-two-numbers
0007-reverse-integer
0012-integer-to-roman
0043-multiply-strings
0048-rotate-image
0050-powx-n
0069-sqrtx
0070-climbing-stairs
0202-happy-number
0204-count-primes
0224-basic-calculator
0231-power-of-two
0241-different-ways-to-add-parentheses
0264-ugly-number-ii
0273-integer-to-english-words
0326-power-of-three
0342-power-of-four
0368-largest-divisible-subset
0371-sum-of-two-integers
0380-insert-delete-getrandom-o1
0415-add-strings
0539-minimum-time-difference
0564-find-the-closest-palindrome
0592-fraction-addition-and-subtraction
0650-2-keys-keyboard
0670-maximum-swap
0679-24-game
0797-rabbits-in-forest
0804-rotated-digits
0826-soup-servings
0867-new-21-game
0870-magic-squares-in-grid
0900-reordered-power-of-2
0912-random-pick-with-weight
1014-k-closest-points-to-origin
1240-stone-game-ii
1411-convert-binary-number-in-a-linked-list-to-integer
1421-find-numbers-with-even-number-of-digits
1426-find-n-unique-integers-sum-up-to-zero
1448-maximum-69-number
1477-product-of-the-last-k-numbers
1500-count-largest-group
1529-max-difference-you-can-get-from-changing-an-integer
1631-number-of-sub-arrays-with-odd-sum
1642-water-bottles
1889-check-if-number-is-a-sum-of-powers-of-three
1951-find-the-winner-of-the-circular-game
1993-sum-of-all-subset-xor-totals
2050-count-good-numbers
2155-find-missing-observations
2202-sum-of-k-mirror-numbers
2415-count-the-number-of-ideal-arrays
2432-number-of-zero-filled-subarrays
2448-count-number-of-bad-pairs
2610-closest-prime-numbers-in-range
2645-pass-the-pillow
2704-maximum-difference-by-remapping-a-digit
2716-prime-subtraction-operation
2802-find-the-punishment-number-of-an-integer
2903-insert-greatest-common-divisors-in-linked-list
2998-count-symmetric-integers
3001-apply-operations-to-maximize-score
3172-divisible-and-non-divisible-sums-difference
3201-distribute-candies-among-children-ii
3227-find-missing-and-repeated-values
3243-count-the-number-of-powerful-integers
3277-find-the-number-of-ways-to-place-people-ii
3278-find-the-number-of-ways-to-place-people-i
3279-alice-and-bob-playing-flower-game
3321-type-of-triangle
3548-find-the-count-of-good-integers
3555-final-array-state-after-k-multiplication-operations-i
3600-find-the-k-th-character-in-string-game-i
3630-total-characters-in-string-after-transformations-ii
3637-count-number-of-balanced-permutations
3682-count-the-number-of-arrays-with-k-matching-adjacent-elements
3744-minimum-operations-to-make-array-elements-zero
3830-find-closest-person
3859-maximum-product-of-two-digits

Simulation

0043-multiply-strings
0054-spiral-matrix
0415-add-strings
0498-diagonal-traverse
0592-fraction-addition-and-subtraction
0874-backspace-string-compare
0906-walking-robot-simulation
0921-spiral-matrix-iii
1642-water-bottles
1667-find-kth-bit-in-nth-binary-string
1803-average-waiting-time
1951-find-the-winner-of-the-circular-game
2006-find-the-student-that-will-replace-the-chalk
2021-remove-all-occurrences-of-a-substring
2048-build-array-from-permutation
2076-sum-of-digits-of-string-after-convert
2132-convert-1d-array-into-2d-array
2155-find-missing-observations
2232-adding-spaces-to-a-string
2265-partition-array-according-to-given-pivot
2343-count-unguarded-cells-in-the-grid
2411-spiral-matrix-iv
2479-meeting-rooms-iii
2551-apply-operations-to-an-array
2645-pass-the-pillow
2692-take-gifts-from-the-richest-pile
2695-find-score-of-an-array-after-marking-all-elements
2800-minimum-string-length-after-removing-substrings
2846-robot-collisions
3332-minimum-operations-to-exceed-threshold-value-ii
3434-find-the-number-of-distinct-colors-among-the-balls
3555-final-array-state-after-k-multiplication-operations-i
3600-find-the-k-th-character-in-string-game-i
3790-fruits-into-baskets-ii

Recursion

0002-add-two-numbers
0010-regular-expression-matching
0021-merge-two-sorted-lists
0050-powx-n
0143-reorder-list
0224-basic-calculator
0231-power-of-two
0241-different-ways-to-add-parentheses
0273-integer-to-english-words
0326-power-of-three
0342-power-of-four
0394-decode-string
1197-parsing-a-boolean-expression
1667-find-kth-bit-in-nth-binary-string
1951-find-the-winner-of-the-circular-game
2050-count-good-numbers
3600-find-the-k-th-character-in-string-game-i

Queue

0239-sliding-window-maximum
0859-design-circular-deque
0892-shortest-subarray-with-sum-at-least-k
1951-find-the-winner-of-the-circular-game
2180-maximum-number-of-tasks-you-can-assign
2527-count-subarrays-with-fixed-bounds
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i

String

0005-longest-palindromic-substring
0008-string-to-integer-atoi
0010-regular-expression-matching
0012-integer-to-roman
0014-longest-common-prefix
0017-letter-combinations-of-a-phone-number
0020-valid-parentheses
0038-count-and-say
0043-multiply-strings
0076-minimum-window-substring
0127-word-ladder
0139-word-break
0151-reverse-words-in-a-string
0179-largest-number
0205-isomorphic-strings
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0212-word-search-ii
0214-shortest-palindrome
0224-basic-calculator
0241-different-ways-to-add-parentheses
0257-binary-tree-paths
0273-integer-to-english-words
0297-serialize-and-deserialize-binary-tree
0299-bulls-and-cows
0316-remove-duplicate-letters
0394-decode-string
0402-remove-k-digits
0415-add-strings
0424-longest-repeating-character-replacement
0482-license-key-formatting
0539-minimum-time-difference
0551-student-attendance-record-i
0557-reverse-words-in-a-string-iii
0564-find-the-closest-palindrome
0592-fraction-addition-and-subtraction
0664-strange-printer
0678-valid-parenthesis-string
0680-valid-palindrome-ii
0726-number-of-atoms
0768-partition-labels
0812-rotate-string
0868-push-dominoes
0874-backspace-string-compare
0920-uncommon-words-from-two-sentences
0952-word-subsets
0957-minimum-add-to-make-parentheses-valid
0965-unique-email-addresses
1023-time-based-key-value-store
1058-lexicographically-smallest-equivalent-string
1093-recover-a-tree-from-preorder-traversal
1160-letter-tile-possibilities
1170-shortest-common-supersequence
1197-parsing-a-boolean-expression
1250-longest-common-subsequence
1298-reverse-substrings-between-each-pair-of-parentheses
1302-delete-characters-to-make-fancy-string
1304-longest-happy-string
1350-remove-sub-folders-from-the-filesystem
1460-number-of-substrings-containing-all-three-characters
1473-find-the-longest-substring-containing-vowels-in-even-counts
1502-construct-k-palindrome-strings
1516-the-k-th-lexicographical-string-of-all-happy-strings-of-length-n
1524-string-matching-in-an-array
1537-maximum-score-after-splitting-a-string
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
1667-find-kth-bit-in-nth-binary-string
1700-minimum-time-to-make-rope-colorful
1715-split-a-string-into-the-max-number-of-unique-substrings
1720-crawler-log-folder
1756-minimum-deletions-to-make-string-balanced
1770-minimum-deletions-to-make-character-frequencies-unique
1786-count-the-number-of-consistent-strings
1818-maximum-score-from-removing-substrings
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1915-check-if-one-string-swap-can-make-strings-equal
1923-sentence-similarity-iii
2021-remove-all-occurrences-of-a-substring
2059-unique-length-3-palindromic-subsequences
2076-sum-of-digits-of-string-after-convert
2079-delete-duplicate-folders-in-system
2095-minimum-number-of-swaps-to-make-the-string-balanced
2107-find-unique-binary-string
2140-longest-subsequence-repeated-k-times
2163-kth-distinct-string-in-an-array
2217-step-by-step-directions-from-a-binary-tree-node-to-another
2220-find-all-possible-recipes-from-given-supplies
2221-check-if-a-parentheses-string-can-be-valid
2232-adding-spaces-to-a-string
2237-longest-palindrome-by-concatenating-two-letter-words
2300-construct-string-with-repeat-limit
2346-largest-3-same-digit-number-in-string
2395-longest-binary-subsequence-less-than-or-equal-to-k
2414-move-pieces-to-obtain-a-string
2456-construct-smallest-number-from-di-string
2463-minimum-recolors-to-get-k-consecutive-black-blocks
2465-shifting-letters-ii
2494-sum-of-prefix-scores-of-strings
2502-sort-the-people
2520-using-a-robot-to-print-the-lexicographically-smallest-string
2580-circular-sentence
2599-take-k-of-each-character-from-left-and-right
2691-count-vowel-strings-in-ranges
2727-number-of-senior-citizens
2755-extra-characters-in-a-string
2800-minimum-string-length-after-removing-substrings
3142-longest-unequal-adjacent-groups-subsequence-ii
3143-longest-unequal-adjacent-groups-subsequence-i
3174-minimum-number-of-changes-to-make-binary-string-beautiful
3194-find-words-containing-character
3195-separate-black-and-white-balls
3235-minimum-cost-to-convert-string-i
3243-count-the-number-of-powerful-integers
3276-minimum-number-of-pushes-to-type-word-ii
3309-count-prefix-and-suffix-pairs-i
3329-find-the-length-of-the-longest-common-prefix
3360-minimum-deletions-to-make-string-k-special
3396-valid-word
3445-lexicographically-minimum-string-after-removing-stars
3455-minimum-length-of-string-after-operations
3569-count-of-substrings-containing-every-vowel-and-k-consonants-ii
3617-find-the-original-typed-string-i
3618-find-the-original-typed-string-ii
3630-total-characters-in-string-after-transformations-ii
3637-count-number-of-balanced-permutations
3683-find-the-lexicographically-largest-string-from-the-box-i
3753-maximum-difference-between-even-and-odd-frequency-i

Stack

0020-valid-parentheses
0084-largest-rectangle-in-histogram
0143-reorder-list
0145-binary-tree-postorder-traversal
0173-binary-search-tree-iterator
0224-basic-calculator
0316-remove-duplicate-letters
0394-decode-string
0402-remove-k-digits
0678-valid-parenthesis-string
0726-number-of-atoms
0776-n-ary-tree-postorder-traversal
0780-max-chunks-to-make-sorted
0874-backspace-string-compare
0937-online-stock-span
0957-minimum-add-to-make-parentheses-valid
1002-maximum-width-ramp
1197-parsing-a-boolean-expression
1298-reverse-substrings-between-each-pair-of-parentheses
1497-design-a-stack-with-increment-operation
1570-final-prices-with-a-special-discount-in-a-shop
1628-count-submatrices-with-all-ones
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1720-crawler-log-folder
1756-minimum-deletions-to-make-string-balanced
1818-maximum-score-from-removing-substrings
2021-remove-all-occurrences-of-a-substring
2095-minimum-number-of-swaps-to-make-the-string-balanced
2221-check-if-a-parentheses-string-can-be-valid
2456-construct-smallest-number-from-di-string
2520-using-a-robot-to-print-the-lexicographically-smallest-string
2800-minimum-string-length-after-removing-substrings
2846-robot-collisions
3001-apply-operations-to-maximize-score
3181-find-building-where-alice-and-bob-can-meet
3445-lexicographically-minimum-string-after-removing-stars

Tree

0099-recover-binary-search-tree
0101-symmetric-tree
0102-binary-tree-level-order-traversal
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0108-convert-sorted-array-to-binary-search-tree
0110-balanced-binary-tree
0145-binary-tree-postorder-traversal
0173-binary-search-tree-iterator
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0257-binary-tree-paths
0297-serialize-and-deserialize-binary-tree
0515-find-largest-value-in-each-tree-row
0530-minimum-absolute-difference-in-bst
0572-subtree-of-another-tree
0617-merge-two-binary-trees
0776-n-ary-tree-postorder-traversal
0789-kth-largest-element-in-a-stream
0988-flip-equivalent-binary-trees
1093-recover-a-tree-from-preorder-traversal
1218-lowest-common-ancestor-of-deepest-leaves
1387-find-elements-in-a-contaminated-binary-tree
1484-linked-list-in-binary-tree
1544-count-good-nodes-in-binary-tree
1653-number-of-good-leaf-nodes-pairs
1731-even-odd-tree
2217-step-by-step-directions-from-a-binary-tree-node-to-another
2306-create-binary-tree-from-descriptions
2400-minimum-score-after-removals-on-a-tree
2493-reverse-odd-levels-of-binary-tree
2558-minimum-number-of-operations-to-sort-a-binary-tree-by-level
2564-most-profitable-path-in-a-tree
2646-kth-largest-sum-in-a-binary-tree
2677-cousins-in-binary-tree-ii
3058-maximum-number-of-k-divisible-components
3633-maximize-the-number-of-target-nodes-after-connecting-trees-i
3645-maximize-the-number-of-target-nodes-after-connecting-trees-ii

Binary Tree

0099-recover-binary-search-tree
0101-symmetric-tree
0102-binary-tree-level-order-traversal
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0108-convert-sorted-array-to-binary-search-tree
0110-balanced-binary-tree
0145-binary-tree-postorder-traversal
0173-binary-search-tree-iterator
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0257-binary-tree-paths
0297-serialize-and-deserialize-binary-tree
0515-find-largest-value-in-each-tree-row
0530-minimum-absolute-difference-in-bst
0572-subtree-of-another-tree
0617-merge-two-binary-trees
0789-kth-largest-element-in-a-stream
0988-flip-equivalent-binary-trees
1093-recover-a-tree-from-preorder-traversal
1218-lowest-common-ancestor-of-deepest-leaves
1387-find-elements-in-a-contaminated-binary-tree
1484-linked-list-in-binary-tree
1544-count-good-nodes-in-binary-tree
1653-number-of-good-leaf-nodes-pairs
1731-even-odd-tree
2217-step-by-step-directions-from-a-binary-tree-node-to-another
2306-create-binary-tree-from-descriptions
2493-reverse-odd-levels-of-binary-tree
2558-minimum-number-of-operations-to-sort-a-binary-tree-by-level
2646-kth-largest-sum-in-a-binary-tree
2677-cousins-in-binary-tree-ii

Sliding Window

0076-minimum-window-substring
0209-minimum-size-subarray-sum
0239-sliding-window-maximum
0424-longest-repeating-character-replacement
0594-longest-harmonious-subsequence
0632-smallest-range-covering-elements-from-k-lists
0867-new-21-game
0892-shortest-subarray-with-sum-at-least-k
0940-fruit-into-baskets
1046-max-consecutive-ones-iii
1460-number-of-substrings-containing-all-three-characters
1586-longest-subarray-of-1s-after-deleting-one-element
1813-maximum-erasure-value
2229-maximum-fruits-harvested-after-at-most-k-steps
2255-minimum-swaps-to-group-all-1s-together-ii
2394-count-subarrays-with-score-less-than-k
2463-minimum-recolors-to-get-k-consecutive-black-blocks
2498-smallest-subarrays-with-maximum-bitwise-or
2527-count-subarrays-with-fixed-bounds
2552-maximum-sum-of-distinct-subarrays-with-length-k
2599-take-k-of-each-character-from-left-and-right
2626-count-the-number-of-good-subarrays
2856-count-complete-subarrays-in-an-array
3213-count-subarrays-where-max-element-appears-at-least-k-times
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3483-alternating-groups-ii
3522-find-the-power-of-k-size-subarrays-i
3569-count-of-substrings-containing-every-vowel-and-k-consonants-ii
3743-reschedule-meetings-for-maximum-free-time-i

Divide and Conquer

0004-median-of-two-sorted-arrays
0023-merge-k-sorted-lists
0053-maximum-subarray
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0108-convert-sorted-array-to-binary-search-tree
0169-majority-element
0190-reverse-bits
0191-number-of-1-bits
0215-kth-largest-element-in-an-array
0240-search-a-2d-matrix-ii
0347-top-k-frequent-elements
0948-sort-an-array
1014-k-closest-points-to-origin
2280-count-good-triplets-in-an-array

Heap (Priority Queue)

0023-merge-k-sorted-lists
0215-kth-largest-element-in-an-array
0239-sliding-window-maximum
0264-ugly-number-ii
0295-find-median-from-data-stream
0347-top-k-frequent-elements
0407-trapping-rain-water-ii
0621-task-scheduler
0632-smallest-range-covering-elements-from-k-lists
0789-kth-largest-element-in-a-stream
0892-shortest-subarray-with-sum-at-least-k
0948-sort-an-array
1014-k-closest-points-to-origin
1304-longest-happy-string
1325-path-with-maximum-probability
1478-maximum-number-of-events-that-can-be-attended
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1917-maximum-average-pass-ratio
2054-the-number-of-the-smallest-unoccupied-chair
2267-minimum-difference-in-sums-after-removal-of-elements
2300-construct-string-with-repeat-limit
2375-minimum-obstacle-removal-to-reach-corner
2434-design-a-number-container-system
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2479-meeting-rooms-iii
2488-divide-intervals-into-minimum-number-of-groups
2588-maximum-number-of-points-from-grid-queries
2616-maximal-score-after-applying-k-operations
2681-put-marbles-in-bags
2692-take-gifts-from-the-richest-pile
2695-find-score-of-an-array-after-marking-all-elements
2711-minimum-time-to-visit-a-cell-in-a-grid
2803-modify-graph-edge-weights
3181-find-building-where-alice-and-bob-can-meet
3332-minimum-operations-to-exceed-threshold-value-ii
3445-lexicographically-minimum-string-after-removing-stars
3555-final-array-state-after-k-multiplication-operations-i
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii
3647-zero-array-transformation-iii

Merge Sort

0023-merge-k-sorted-lists
0948-sort-an-array
2280-count-good-triplets-in-an-array

Bucket Sort

0347-top-k-frequent-elements
0948-sort-an-array

Radix Sort

0948-sort-an-array

Counting Sort

0169-majority-element
0229-majority-element-ii
0274-h-index
0299-bulls-and-cows
0347-top-k-frequent-elements
0594-longest-harmonious-subsequence
0621-task-scheduler
0900-reordered-power-of-2
0920-uncommon-words-from-two-sentences
0948-sort-an-array
1160-letter-tile-possibilities
1227-number-of-equivalent-domino-pairs
1396-count-servers-that-communicate
1502-construct-k-palindrome-strings
1510-find-lucky-integer-in-an-array
1620-check-if-array-pairs-are-divisible-by-k
1786-count-the-number-of-consistent-strings
1901-equal-sum-arrays-with-minimum-number-of-operations
1915-check-if-one-string-swap-can-make-strings-equal
2140-longest-subsequence-repeated-k-times
2163-kth-distinct-string-in-an-array
2237-longest-palindrome-by-concatenating-two-letter-words
2300-construct-string-with-repeat-limit
2308-divide-array-into-equal-pairs
2356-largest-combination-with-bitwise-and-greater-than-zero
2448-count-number-of-bad-pairs
2494-sum-of-prefix-scores-of-strings
2614-maximum-count-of-positive-integer-and-negative-integer
3276-minimum-number-of-pushes-to-type-word-ii
3360-minimum-deletions-to-make-string-k-special
3455-minimum-length-of-string-after-operations
3630-total-characters-in-string-after-transformations-ii
3753-maximum-difference-between-even-and-odd-frequency-i

Dynamic Programming

0005-longest-palindromic-substring
0010-regular-expression-matching
0053-maximum-subarray
0055-jump-game
0064-minimum-path-sum
0070-climbing-stairs
0118-pascals-triangle
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0139-word-break
0152-maximum-product-subarray
0198-house-robber
0213-house-robber-ii
0241-different-ways-to-add-parentheses
0264-ugly-number-ii
0322-coin-change
0338-counting-bits
0368-largest-divisible-subset
0416-partition-equal-subset-sum
0494-target-sum
0650-2-keys-keyboard
0664-strange-printer
0678-valid-parenthesis-string
0804-rotated-digits
0806-domino-and-tromino-tiling
0826-soup-servings
0867-new-21-game
0868-push-dominoes
0905-length-of-longest-fibonacci-subsequence
0934-bitwise-ors-of-subarrays
1025-minimum-cost-for-tickets
1170-shortest-common-supersequence
1196-filling-bookcase-shelves
1240-stone-game-ii
1250-longest-common-subsequence
1402-count-square-submatrices-with-all-ones
1456-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance
1511-count-number-of-teams
1586-longest-subarray-of-1s-after-deleting-one-element
1628-count-submatrices-with-all-ones
1631-number-of-sub-arrays-with-odd-sum
1700-minimum-time-to-make-rope-colorful
1756-minimum-deletions-to-make-string-balanced
1766-minimum-number-of-removals-to-make-mountain-array
1849-maximum-absolute-sum-of-any-subarray
1851-maximum-number-of-events-that-can-be-attended-ii
2028-the-earliest-and-latest-rounds-where-players-compete
2067-maximum-number-of-points-with-cost
2090-number-of-ways-to-arrive-at-destination
2262-solving-questions-with-brainpower
2267-minimum-difference-in-sums-after-removal-of-elements
2395-longest-binary-subsequence-less-than-or-equal-to-k
2415-count-the-number-of-ideal-arrays
2554-minimum-total-distance-traveled
2562-count-ways-to-build-good-strings
2755-extra-characters-in-a-string
2794-maximum-number-of-moves-in-a-grid
2882-ways-to-express-an-integer-as-sum-of-powers
3142-longest-unequal-adjacent-groups-subsequence-ii
3143-longest-unequal-adjacent-groups-subsequence-i
3243-count-the-number-of-powerful-integers
3490-find-the-maximum-length-of-valid-subsequence-i
3491-find-the-maximum-length-of-valid-subsequence-ii
3618-find-the-original-typed-string-ii
3630-total-characters-in-string-after-transformations-ii
3637-count-number-of-balanced-permutations
3648-find-the-maximum-number-of-fruits-collected
3733-length-of-longest-v-shaped-diagonal-segment

Shortest Path

1325-path-with-maximum-probability
1456-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
2090-number-of-ways-to-arrive-at-destination
2171-second-minimum-time-to-reach-destination
2375-minimum-obstacle-removal-to-reach-corner
2711-minimum-time-to-visit-a-cell-in-a-grid
2803-modify-graph-edge-weights
3235-minimum-cost-to-convert-string-i
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii

Binary Indexed Tree

1511-count-number-of-teams
2280-count-good-triplets-in-an-array
3181-find-building-where-alice-and-bob-can-meet

Design

0146-lru-cache
0173-binary-search-tree-iterator
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0295-find-median-from-data-stream
0297-serialize-and-deserialize-binary-tree
0303-range-sum-query-immutable
0380-insert-delete-getrandom-o1
0432-all-oone-data-structure
0729-my-calendar-i
0731-my-calendar-ii
0789-kth-largest-element-in-a-stream
0816-design-hashset
0859-design-circular-deque
0937-online-stock-span
1023-time-based-key-value-store
1387-find-elements-in-a-contaminated-binary-tree
1477-product-of-the-last-k-numbers
1497-design-a-stack-with-increment-operation
1995-finding-pairs-with-a-certain-sum
2434-design-a-number-container-system

Binary Search Tree

0099-recover-binary-search-tree
0108-convert-sorted-array-to-binary-search-tree
0173-binary-search-tree-iterator
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0530-minimum-absolute-difference-in-bst
0789-kth-largest-element-in-a-stream

Data Stream

0295-find-median-from-data-stream
0789-kth-largest-element-in-a-stream
0937-online-stock-span
1477-product-of-the-last-k-numbers

Backtracking

0017-letter-combinations-of-a-phone-number
0039-combination-sum
0040-combination-sum-ii
0212-word-search-ii
0257-binary-tree-paths
0494-target-sum
0679-24-game
1160-letter-tile-possibilities
1516-the-k-th-lexicographical-string-of-all-happy-strings-of-length-n
1715-split-a-string-into-the-max-number-of-unique-substrings
1819-construct-the-lexicographically-largest-valid-sequence
1993-sum-of-all-subset-xor-totals
2107-find-unique-binary-string
2140-longest-subsequence-repeated-k-times
2170-count-number-of-maximum-bitwise-or-subsets
2456-construct-smallest-number-from-di-string
2802-find-the-punishment-number-of-an-integer

Prefix Sum

0209-minimum-size-subarray-sum
0303-range-sum-query-immutable
0731-my-calendar-ii
0892-shortest-subarray-with-sum-at-least-k
0912-random-pick-with-weight
1046-max-consecutive-ones-iii
1240-stone-game-ii
1435-xor-queries-of-a-subarray
1473-find-the-longest-substring-containing-vowels-in-even-counts
1477-product-of-the-last-k-numbers
1537-maximum-score-after-splitting-a-string
1631-number-of-sub-arrays-with-odd-sum
1694-make-sum-divisible-by-p
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1940-maximum-xor-for-each-query
2006-find-the-student-that-will-replace-the-chalk
2059-unique-length-3-palindromic-subsequences
2145-grid-game
2229-maximum-fruits-harvested-after-at-most-k-steps
2249-count-the-hidden-sequences
2358-number-of-ways-to-split-array
2394-count-subarrays-with-score-less-than-k
2465-shifting-letters-ii
2488-divide-intervals-into-minimum-number-of-groups
2529-range-product-queries-of-powers
2691-count-vowel-strings-in-ranges
2915-count-of-interesting-subarrays
3427-special-array-ii
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3618-find-the-original-typed-string-ii
3639-zero-array-transformation-i
3643-zero-array-transformation-ii
3647-zero-array-transformation-iii
3789-maximize-subarrays-after-removing-one-conflicting-pair

Game Theory

1240-stone-game-ii

Bit Manipulation

0190-reverse-bits
0191-number-of-1-bits
0231-power-of-two
0338-counting-bits
0342-power-of-four
0371-sum-of-two-integers
0476-number-complement
0934-bitwise-ors-of-subarrays
1435-xor-queries-of-a-subarray
1473-find-the-longest-substring-containing-vowels-in-even-counts
1487-cinema-seat-allocation
1786-count-the-number-of-consistent-strings
1940-maximum-xor-for-each-query
1993-sum-of-all-subset-xor-totals
2059-unique-length-3-palindromic-subsequences
2170-count-number-of-maximum-bitwise-or-subsets
2308-divide-array-into-equal-pairs
2323-minimum-bit-flips-to-convert-number
2356-largest-combination-with-bitwise-and-greater-than-zero
2400-minimum-score-after-removals-on-a-tree
2498-smallest-subarrays-with-maximum-bitwise-or
2503-longest-subarray-with-maximum-bitwise-and
2509-minimize-xor
2529-range-product-queries-of-powers
2533-bitwise-xor-of-all-pairings
2766-find-the-prefix-common-array-of-two-arrays
2792-neighboring-bitwise-xor
2837-minimum-operations-to-make-the-integer-zero
3291-find-if-array-can-be-sorted
3348-minimum-cost-walk-in-weighted-graph
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3600-find-the-k-th-character-in-string-game-i
3744-minimum-operations-to-make-array-elements-zero

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0023-merge-k-sorted-lists
0083-remove-duplicates-from-sorted-list
0086-partition-list
0092-reverse-linked-list-ii
0141-linked-list-cycle
0143-reorder-list
0146-lru-cache
0160-intersection-of-two-linked-lists
0432-all-oone-data-structure
0725-split-linked-list-in-parts
0816-design-hashset
0859-design-circular-deque
0908-middle-of-the-linked-list
1411-convert-binary-number-in-a-linked-list-to-integer
1484-linked-list-in-binary-tree
2411-spiral-matrix-iv
2903-insert-greatest-common-divisors-in-linked-list
3501-delete-nodes-from-linked-list-present-in-array

Number Theory

0204-count-primes
2415-count-the-number-of-ideal-arrays
2610-closest-prime-numbers-in-range
2716-prime-subtraction-operation
2903-insert-greatest-common-divisors-in-linked-list
3001-apply-operations-to-maximize-score

Brainteaser

2503-longest-subarray-with-maximum-bitwise-and
2533-bitwise-xor-of-all-pairings
2837-minimum-operations-to-make-the-integer-zero

Memoization

0070-climbing-stairs
0139-word-break
0241-different-ways-to-add-parentheses
2028-the-earliest-and-latest-rounds-where-players-compete
2395-longest-binary-subsequence-less-than-or-equal-to-k
3733-length-of-longest-v-shaped-diagonal-segment

Rolling Hash

0214-shortest-palindrome
3309-count-prefix-and-suffix-pairs-i

String Matching

0214-shortest-palindrome
0572-subtree-of-another-tree
0812-rotate-string
1524-string-matching-in-an-array
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
3309-count-prefix-and-suffix-pairs-i

Hash Function

0214-shortest-palindrome
0572-subtree-of-another-tree
0816-design-hashset
2079-delete-duplicate-folders-in-system
3309-count-prefix-and-suffix-pairs-i

Trie

0014-longest-common-prefix
0139-word-break
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0212-word-search-ii
0386-lexicographical-numbers
0440-k-th-smallest-in-lexicographical-order
1350-remove-sub-folders-from-the-filesystem
2079-delete-duplicate-folders-in-system
2494-sum-of-prefix-scores-of-strings
2755-extra-characters-in-a-string
3309-count-prefix-and-suffix-pairs-i
3329-find-the-length-of-the-longest-common-prefix

Segment Tree

0729-my-calendar-i
0731-my-calendar-ii
2280-count-good-triplets-in-an-array
3181-find-building-where-alice-and-bob-can-meet
3789-maximize-subarrays-after-removing-one-conflicting-pair
3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii

Ordered Set

0729-my-calendar-i
0731-my-calendar-ii
2280-count-good-triplets-in-an-array
2434-design-a-number-container-system
3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii

Doubly-Linked List

0146-lru-cache
0432-all-oone-data-structure

Monotonic Stack

0084-largest-rectangle-in-histogram
0316-remove-duplicate-letters
0402-remove-k-digits
0780-max-chunks-to-make-sorted
0937-online-stock-span
1002-maximum-width-ramp
1570-final-prices-with-a-special-discount-in-a-shop
1628-count-submatrices-with-all-ones
1679-shortest-subarray-to-be-removed-to-make-array-sorted
3001-apply-operations-to-maximize-score
3181-find-building-where-alice-and-bob-can-meet

Enumeration

0204-count-primes
0900-reordered-power-of-2
1656-count-good-triplets
1993-sum-of-all-subset-xor-totals
2140-longest-subsequence-repeated-k-times
2170-count-number-of-maximum-bitwise-or-subsets
2202-sum-of-k-mirror-numbers
2215-finding-3-digit-even-numbers
2837-minimum-operations-to-make-the-integer-zero
2998-count-symmetric-integers
3201-distribute-candies-among-children-ii
3277-find-the-number-of-ways-to-place-people-ii
3278-find-the-number-of-ways-to-place-people-i
3459-find-the-minimum-area-to-cover-all-ones-ii
3548-find-the-count-of-good-integers
3683-find-the-lexicographically-largest-string-from-the-box-i
3741-reschedule-meetings-for-maximum-free-time-ii
3789-maximize-subarrays-after-removing-one-conflicting-pair

Randomized

0380-insert-delete-getrandom-o1
0912-random-pick-with-weight

Quickselect

0215-kth-largest-element-in-an-array
0347-top-k-frequent-elements
1014-k-closest-points-to-origin

Monotonic Queue

0239-sliding-window-maximum
0892-shortest-subarray-with-sum-at-least-k
2180-maximum-number-of-tasks-you-can-assign
2527-count-subarrays-with-fixed-bounds

Iterator

0173-binary-search-tree-iterator

Geometry

1014-k-closest-points-to-origin
3277-find-the-number-of-ways-to-place-people-ii
3278-find-the-number-of-ways-to-place-people-i

Eulerian Circuit

2201-valid-arrangement-of-pairs

Combinatorics

1993-sum-of-all-subset-xor-totals
2415-count-the-number-of-ideal-arrays
3201-distribute-candies-among-children-ii
3548-find-the-count-of-good-integers
3637-count-number-of-balanced-permutations
3682-count-the-number-of-arrays-with-k-matching-adjacent-elements

Probability and Statistics

0826-soup-servings
0867-new-21-game