leetcode_solutions

Two Pointers

0018-4sum
0019-remove-nth-node-from-end-of-list
0026-remove-duplicates-from-sorted-array
0061-rotate-list
0075-sort-colors
0141-linked-list-cycle
0142-linked-list-cycle-ii
0160-intersection-of-two-linked-lists
0344-reverse-string
2572-append-characters-to-string-to-make-subsequence

String

0003-longest-substring-without-repeating-characters
0008-string-to-integer-atoi
0014-longest-common-prefix
0131-palindrome-partitioning
0344-reverse-string
0409-longest-palindrome
0686-repeated-string-match
1044-find-common-characters
2572-append-characters-to-string-to-make-subsequence

Array

0001-two-sum
0018-4sum
0026-remove-duplicates-from-sorted-array
0039-combination-sum
0040-combination-sum-ii
0074-search-a-2d-matrix
0075-sort-colors
0078-subsets
0090-subsets-ii
0120-triangle
0128-longest-consecutive-sequence
0169-majority-element
0229-majority-element-ii
0485-max-consecutive-ones
0493-reverse-pairs
0560-subarray-sum-equals-k
0954-maximum-sum-circular-subarray
0982-minimum-increment-to-make-array-unique
1016-subarray-sums-divisible-by-k
1044-find-common-characters
1137-height-checker
1217-relative-sort-array

Binary Search

0074-search-a-2d-matrix
0493-reverse-pairs

Matrix

0074-search-a-2d-matrix

Math

0002-add-two-numbers
0050-powx-n
0060-permutation-sequence

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0025-reverse-nodes-in-k-group
0050-powx-n
0060-permutation-sequence

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0128-longest-consecutive-sequence
0141-linked-list-cycle
0142-linked-list-cycle-ii
0160-intersection-of-two-linked-lists
0169-majority-element
0229-majority-element-ii
0409-longest-palindrome
0560-subarray-sum-equals-k
1016-subarray-sums-divisible-by-k
1044-find-common-characters
1217-relative-sort-array

Divide and Conquer

0169-majority-element
0493-reverse-pairs
0954-maximum-sum-circular-subarray

Sorting

0018-4sum
0075-sort-colors
0169-majority-element
0229-majority-element-ii
0982-minimum-increment-to-make-array-unique
1137-height-checker
1217-relative-sort-array

Counting

0169-majority-element
0229-majority-element-ii

Binary Indexed Tree

0493-reverse-pairs

Segment Tree

0493-reverse-pairs

Merge Sort

0493-reverse-pairs

Ordered Set

0493-reverse-pairs

Union Find

0128-longest-consecutive-sequence

Greedy

0409-longest-palindrome
0982-minimum-increment-to-make-array-unique
2572-append-characters-to-string-to-make-subsequence

Prefix Sum

0560-subarray-sum-equals-k
1016-subarray-sums-divisible-by-k

Sliding Window

0003-longest-substring-without-repeating-characters

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0025-reverse-nodes-in-k-group
0061-rotate-list
0141-linked-list-cycle
0142-linked-list-cycle-ii
0160-intersection-of-two-linked-lists
0237-delete-node-in-a-linked-list

Database

0197-rising-temperature
0570-managers-with-at-least-5-direct-reports
0577-employee-bonus
0584-find-customer-referee
0595-big-countries
0596-classes-more-than-5-students
0619-biggest-single-number
0620-not-boring-movies
1135-customers-who-bought-all-products
1153-product-sales-analysis-i
1155-product-sales-analysis-iii
1161-project-employees-i
1182-game-play-analysis-iv
1245-user-activity-for-the-past-30-days-i
1258-article-views-i
1292-immediate-food-delivery-ii
1317-monthly-transactions-i
1338-queries-quality-and-percentage
1390-average-selling-price
1415-students-and-examinations
1509-replace-employee-id-with-the-unique-identifier
1724-customer-who-visited-but-did-not-make-any-transactions
1773-percentage-of-users-attended-a-contest
1801-average-time-of-process-per-machine
1827-invalid-tweets
1877-find-followers-count
1908-recyclable-and-low-fat-products
2087-confirmation-rate
2495-number-of-unique-subjects-taught-by-each-teacher

Backtracking

0039-combination-sum
0040-combination-sum-ii
0078-subsets
0090-subsets-ii
0131-palindrome-partitioning

Bit Manipulation

0078-subsets
0090-subsets-ii

Dynamic Programming

0120-triangle
0131-palindrome-partitioning
0954-maximum-sum-circular-subarray

Queue

0954-maximum-sum-circular-subarray

Monotonic Queue

0954-maximum-sum-circular-subarray

Counting Sort

0982-minimum-increment-to-make-array-unique
1137-height-checker
1217-relative-sort-array

Trie

0014-longest-common-prefix

String Matching

0686-repeated-string-match

Tree

1114-binary-search-tree-to-greater-sum-tree

Depth-First Search

1114-binary-search-tree-to-greater-sum-tree

Binary Search Tree

1114-binary-search-tree-to-greater-sum-tree

Binary Tree

1114-binary-search-tree-to-greater-sum-tree

Graph

1916-find-center-of-star-graph

LeetCode Topics

Array

0001-two-sum
0015-3sum
0018-4sum
0026-remove-duplicates-from-sorted-array
0031-next-permutation
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0041-first-missing-positive
0042-trapping-rain-water
0048-rotate-image
0053-maximum-subarray
0054-spiral-matrix
0056-merge-intervals
0063-unique-paths-ii
0073-set-matrix-zeroes
0075-sort-colors
0081-search-in-rotated-sorted-array-ii
0088-merge-sorted-array
0121-best-time-to-buy-and-sell-stock
0136-single-number
0152-maximum-product-subarray
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0169-majority-element
0189-rotate-array
0198-house-robber
0209-minimum-size-subarray-sum
0213-house-robber-ii
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0268-missing-number
0283-move-zeroes
0322-coin-change
0350-intersection-of-two-arrays-ii
0416-partition-equal-subset-sum
0455-assign-cookies
0485-max-consecutive-ones
0494-target-sum
0496-next-greater-element-i
0503-next-greater-element-ii
0518-coin-change-ii
0540-single-element-in-a-sorted-array
0560-subarray-sum-equals-k
0624-maximum-distance-in-arrays
0733-flood-fill
0792-binary-search
0890-lemonade-change
0907-koko-eating-bananas
0966-binary-subarrays-with-sum
1036-rotting-oranges
1046-max-consecutive-ones-iii
1050-construct-binary-search-tree-from-preorder-traversal
1227-number-of-equivalent-domino-pairs
1325-path-with-maximum-probability
1364-tuple-with-same-product
1468-check-if-n-and-its-double-exist
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1720-crawler-log-folder
1803-average-waiting-time
1878-check-if-array-is-sorted-and-rotated
1951-find-the-winner-of-the-circular-game
1966-frequency-of-the-most-frequent-element
1993-sum-of-all-subset-xor-totals
2040-minimum-cost-to-reach-destination-in-time
2048-build-array-from-permutation
2058-concatenation-of-array
2308-divide-array-into-equal-pairs
2448-count-number-of-bad-pairs
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2478-longest-nice-subarray
2503-longest-subarray-with-maximum-bitwise-and
2551-apply-operations-to-an-array
2588-maximum-number-of-points-from-grid-queries
2614-maximum-count-of-positive-integer-and-negative-integer
2640-maximum-number-of-integers-to-choose-from-a-range-i
2692-take-gifts-from-the-richest-pile
2695-find-score-of-an-array-after-marking-all-elements
2699-count-the-number-of-fair-pairs
2780-make-costs-of-paths-equal-in-a-binary-tree
2794-maximum-number-of-moves-in-a-grid
2888-minimum-index-of-a-valid-split
3154-maximum-value-of-an-ordered-triplet-i
3171-minimum-equal-sum-of-two-arrays-after-replacing-zeros
3227-find-missing-and-repeated-values
3329-find-the-length-of-the-longest-common-prefix
3348-minimum-cost-walk-in-weighted-graph
3429-special-array-i
3463-alternating-groups-i
3483-alternating-groups-ii
3522-find-the-power-of-k-size-subarrays-i
3621-minimum-operations-to-make-array-values-equal-to-k
3656-minimum-number-of-operations-to-make-elements-in-array-distinct

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0012-integer-to-roman
0041-first-missing-positive
0073-set-matrix-zeroes
0133-clone-graph
0141-linked-list-cycle
0142-linked-list-cycle-ii
0160-intersection-of-two-linked-lists
0169-majority-element
0205-isomorphic-strings
0217-contains-duplicate
0242-valid-anagram
0268-missing-number
0350-intersection-of-two-arrays-ii
0424-longest-repeating-character-replacement
0451-sort-characters-by-frequency
0496-next-greater-element-i
0560-subarray-sum-equals-k
0653-two-sum-iv-input-is-a-bst
0896-smallest-subtree-with-all-the-deepest-nodes
0920-uncommon-words-from-two-sentences
0966-binary-subarrays-with-sum
1029-vertical-order-traversal-of-a-binary-tree
1218-lowest-common-ancestor-of-deepest-leaves
1227-number-of-equivalent-domino-pairs
1364-tuple-with-same-product
1387-find-elements-in-a-contaminated-binary-tree
1460-number-of-substrings-containing-all-three-characters
1468-check-if-n-and-its-double-exist
1890-sum-of-beauty-of-all-substrings
1915-check-if-one-string-swap-can-make-strings-equal
2308-divide-array-into-equal-pairs
2434-design-a-number-container-system
2448-count-number-of-bad-pairs
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2640-maximum-number-of-integers-to-choose-from-a-range-i
2695-find-score-of-an-array-after-marking-all-elements
2888-minimum-index-of-a-valid-split
3227-find-missing-and-repeated-values
3329-find-the-length-of-the-longest-common-prefix
3548-find-the-count-of-good-integers
3621-minimum-operations-to-make-array-values-equal-to-k
3656-minimum-number-of-operations-to-make-elements-in-array-distinct

Two Pointers

0005-longest-palindromic-substring
0015-3sum
0018-4sum
0019-remove-nth-node-from-end-of-list
0026-remove-duplicates-from-sorted-array
0028-find-the-index-of-the-first-occurrence-in-a-string
0031-next-permutation
0042-trapping-rain-water
0075-sort-colors
0088-merge-sorted-array
0125-valid-palindrome
0141-linked-list-cycle
0142-linked-list-cycle-ii
0148-sort-list
0151-reverse-words-in-a-string
0160-intersection-of-two-linked-lists
0189-rotate-array
0234-palindrome-linked-list
0283-move-zeroes
0350-intersection-of-two-arrays-ii
0455-assign-cookies
0653-two-sum-iv-input-is-a-bst
0868-push-dominoes
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
1679-shortest-subarray-to-be-removed-to-make-array-sorted
2216-delete-the-middle-node-of-a-linked-list
2551-apply-operations-to-an-array
2588-maximum-number-of-points-from-grid-queries
2699-count-the-number-of-fair-pairs

Binary Search

0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0081-search-in-rotated-sorted-array-ii
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0209-minimum-size-subarray-sum
0268-missing-number
0350-intersection-of-two-arrays-ii
0540-single-element-in-a-sorted-array
0792-binary-search
0907-koko-eating-bananas
1046-max-consecutive-ones-iii
1468-check-if-n-and-its-double-exist
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1966-frequency-of-the-most-frequent-element
2614-maximum-count-of-positive-integer-and-negative-integer
2640-maximum-number-of-integers-to-choose-from-a-range-i
2699-count-the-number-of-fair-pairs

Sorting

0015-3sum
0018-4sum
0056-merge-intervals
0075-sort-colors
0088-merge-sorted-array
0148-sort-list
0169-majority-element
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0242-valid-anagram
0268-missing-number
0350-intersection-of-two-arrays-ii
0451-sort-characters-by-frequency
0455-assign-cookies
1029-vertical-order-traversal-of-a-binary-tree
1468-check-if-n-and-its-double-exist
1966-frequency-of-the-most-frequent-element
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2588-maximum-number-of-points-from-grid-queries
2640-maximum-number-of-integers-to-choose-from-a-range-i
2695-find-score-of-an-array-after-marking-all-elements
2699-count-the-number-of-fair-pairs
2888-minimum-index-of-a-valid-split

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0025-reverse-nodes-in-k-group
0141-linked-list-cycle
0142-linked-list-cycle-ii
0148-sort-list
0160-intersection-of-two-linked-lists
0206-reverse-linked-list
0234-palindrome-linked-list
0237-delete-node-in-a-linked-list
0328-odd-even-linked-list
0908-middle-of-the-linked-list
2216-delete-the-middle-node-of-a-linked-list
2299-merge-nodes-in-between-zeros

Simulation

0054-spiral-matrix
1803-average-waiting-time
1951-find-the-winner-of-the-circular-game
2048-build-array-from-permutation
2058-concatenation-of-array
2299-merge-nodes-in-between-zeros
2551-apply-operations-to-an-array
2692-take-gifts-from-the-richest-pile
2695-find-score-of-an-array-after-marking-all-elements
3447-clear-digits

Math

0002-add-two-numbers
0012-integer-to-roman
0048-rotate-image
0062-unique-paths
0070-climbing-stairs
0168-excel-sheet-column-title
0189-rotate-array
0268-missing-number
1951-find-the-winner-of-the-circular-game
1993-sum-of-all-subset-xor-totals
2032-largest-odd-number-in-string
2050-count-good-numbers
2448-count-number-of-bad-pairs
2649-count-total-number-of-colored-cells
2998-count-symmetric-integers
3227-find-missing-and-repeated-values
3548-find-the-count-of-good-integers

Recursion

0002-add-two-numbers
0025-reverse-nodes-in-k-group
0206-reverse-linked-list
0234-palindrome-linked-list
1951-find-the-winner-of-the-circular-game
2050-count-good-numbers

Queue

1951-find-the-winner-of-the-circular-game

Stack

0042-trapping-rain-water
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0173-binary-search-tree-iterator
0234-palindrome-linked-list
0496-next-greater-element-i
0503-next-greater-element-ii
0957-minimum-add-to-make-parentheses-valid
1050-construct-binary-search-tree-from-preorder-traversal
1078-remove-outermost-parentheses
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1720-crawler-log-folder
1737-maximum-nesting-depth-of-the-parentheses
2221-check-if-a-parentheses-string-can-be-valid
2456-construct-smallest-number-from-di-string
3447-clear-digits

Monotonic Stack

0042-trapping-rain-water
0496-next-greater-element-i
0503-next-greater-element-ii
1050-construct-binary-search-tree-from-preorder-traversal
1679-shortest-subarray-to-be-removed-to-make-array-sorted

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0012-integer-to-roman
0014-longest-common-prefix
0022-generate-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string
0038-count-and-say
0125-valid-palindrome
0132-palindrome-partitioning-ii
0151-reverse-words-in-a-string
0168-excel-sheet-column-title
0205-isomorphic-strings
0242-valid-anagram
0257-binary-tree-paths
0424-longest-repeating-character-replacement
0451-sort-characters-by-frequency
0516-longest-palindromic-subsequence
0812-rotate-string
0868-push-dominoes
0920-uncommon-words-from-two-sentences
0957-minimum-add-to-make-parentheses-valid
1078-remove-outermost-parentheses
1093-recover-a-tree-from-preorder-traversal
1170-shortest-common-supersequence
1250-longest-common-subsequence
1437-minimum-insertion-steps-to-make-a-string-palindrome
1460-number-of-substrings-containing-all-three-characters
1516-the-k-th-lexicographical-string-of-all-happy-strings-of-length-n
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
1720-crawler-log-folder
1737-maximum-nesting-depth-of-the-parentheses
1890-sum-of-beauty-of-all-substrings
1915-check-if-one-string-swap-can-make-strings-equal
2032-largest-odd-number-in-string
2221-check-if-a-parentheses-string-can-be-valid
2456-construct-smallest-number-from-di-string
2463-minimum-recolors-to-get-k-consecutive-black-blocks
3329-find-the-length-of-the-longest-common-prefix
3447-clear-digits

Greedy

0455-assign-cookies
0624-maximum-distance-in-arrays
0890-lemonade-change
0957-minimum-add-to-make-parentheses-valid
1966-frequency-of-the-most-frequent-element
2032-largest-odd-number-in-string
2221-check-if-a-parentheses-string-can-be-valid
2456-construct-smallest-number-from-di-string
2640-maximum-number-of-integers-to-choose-from-a-range-i
2780-make-costs-of-paths-equal-in-a-binary-tree
3171-minimum-equal-sum-of-two-arrays-after-replacing-zeros

Graph

0133-clone-graph
0547-number-of-provinces
0684-redundant-connection
0744-network-delay-time
1325-path-with-maximum-probability
2040-minimum-cost-to-reach-destination-in-time
2090-number-of-ways-to-arrive-at-destination
3348-minimum-cost-walk-in-weighted-graph

Heap (Priority Queue)

0215-kth-largest-element-in-an-array
0451-sort-characters-by-frequency
0744-network-delay-time
1325-path-with-maximum-probability
2434-design-a-number-container-system
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2588-maximum-number-of-points-from-grid-queries
2692-take-gifts-from-the-richest-pile
2695-find-score-of-an-array-after-marking-all-elements

Shortest Path

0744-network-delay-time
1325-path-with-maximum-probability
2090-number-of-ways-to-arrive-at-destination

Bit Manipulation

0136-single-number
0268-missing-number
1993-sum-of-all-subset-xor-totals
2308-divide-array-into-equal-pairs
2478-longest-nice-subarray
2503-longest-subarray-with-maximum-bitwise-and
3348-minimum-cost-walk-in-weighted-graph

Brainteaser

2503-longest-subarray-with-maximum-bitwise-and

Counting

0169-majority-element
0451-sort-characters-by-frequency
0920-uncommon-words-from-two-sentences
1227-number-of-equivalent-domino-pairs
1364-tuple-with-same-product
1890-sum-of-beauty-of-all-substrings
1915-check-if-one-string-swap-can-make-strings-equal
2308-divide-array-into-equal-pairs
2448-count-number-of-bad-pairs
2614-maximum-count-of-positive-integer-and-negative-integer

Trie

0014-longest-common-prefix
3329-find-the-length-of-the-longest-common-prefix

Dynamic Programming

0005-longest-palindromic-substring
0022-generate-parentheses
0042-trapping-rain-water
0053-maximum-subarray
0062-unique-paths
0063-unique-paths-ii
0070-climbing-stairs
0121-best-time-to-buy-and-sell-stock
0124-binary-tree-maximum-path-sum
0132-palindrome-partitioning-ii
0152-maximum-product-subarray
0198-house-robber
0213-house-robber-ii
0322-coin-change
0416-partition-equal-subset-sum
0494-target-sum
0516-longest-palindromic-subsequence
0518-coin-change-ii
0868-push-dominoes
1170-shortest-common-supersequence
1250-longest-common-subsequence
1437-minimum-insertion-steps-to-make-a-string-palindrome
2040-minimum-cost-to-reach-destination-in-time
2090-number-of-ways-to-arrive-at-destination
2780-make-costs-of-paths-equal-in-a-binary-tree
2794-maximum-number-of-moves-in-a-grid

Matrix

0048-rotate-image
0054-spiral-matrix
0063-unique-paths-ii
0073-set-matrix-zeroes
0733-flood-fill
1036-rotting-oranges
2588-maximum-number-of-points-from-grid-queries
2794-maximum-number-of-moves-in-a-grid
3227-find-missing-and-repeated-values

Divide and Conquer

0053-maximum-subarray
0148-sort-list
0169-majority-element
0215-kth-largest-element-in-an-array

Prefix Sum

0209-minimum-size-subarray-sum
0560-subarray-sum-equals-k
0966-binary-subarrays-with-sum
1046-max-consecutive-ones-iii
1966-frequency-of-the-most-frequent-element

Merge Sort

0148-sort-list

Sliding Window

0003-longest-substring-without-repeating-characters
0209-minimum-size-subarray-sum
0424-longest-repeating-character-replacement
0966-binary-subarrays-with-sum
1046-max-consecutive-ones-iii
1460-number-of-substrings-containing-all-three-characters
1966-frequency-of-the-most-frequent-element
2463-minimum-recolors-to-get-k-consecutive-black-blocks
2478-longest-nice-subarray
3463-alternating-groups-i
3483-alternating-groups-ii
3522-find-the-power-of-k-size-subarrays-i

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string
0812-rotate-string
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence

Depth-First Search

0098-validate-binary-search-tree
0100-same-tree
0104-maximum-depth-of-binary-tree
0110-balanced-binary-tree
0124-binary-tree-maximum-path-sum
0133-clone-graph
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0257-binary-tree-paths
0515-find-largest-value-in-each-tree-row
0543-diameter-of-binary-tree
0547-number-of-provinces
0653-two-sum-iv-input-is-a-bst
0684-redundant-connection
0733-flood-fill
0744-network-delay-time
0896-smallest-subtree-with-all-the-deepest-nodes
1029-vertical-order-traversal-of-a-binary-tree
1093-recover-a-tree-from-preorder-traversal
1218-lowest-common-ancestor-of-deepest-leaves
1387-find-elements-in-a-contaminated-binary-tree

Breadth-First Search

0100-same-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0133-clone-graph
0322-coin-change
0515-find-largest-value-in-each-tree-row
0547-number-of-provinces
0653-two-sum-iv-input-is-a-bst
0684-redundant-connection
0733-flood-fill
0744-network-delay-time
0896-smallest-subtree-with-all-the-deepest-nodes
1029-vertical-order-traversal-of-a-binary-tree
1036-rotting-oranges
1218-lowest-common-ancestor-of-deepest-leaves
1387-find-elements-in-a-contaminated-binary-tree
2588-maximum-number-of-points-from-grid-queries

Union Find

0547-number-of-provinces
0684-redundant-connection
2588-maximum-number-of-points-from-grid-queries
3348-minimum-cost-walk-in-weighted-graph

Backtracking

0022-generate-parentheses
0077-combinations
0257-binary-tree-paths
0494-target-sum
1516-the-k-th-lexicographical-string-of-all-happy-strings-of-length-n
1993-sum-of-all-subset-xor-totals
2456-construct-smallest-number-from-di-string

Tree

0098-validate-binary-search-tree
0100-same-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0110-balanced-binary-tree
0124-binary-tree-maximum-path-sum
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0173-binary-search-tree-iterator
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0257-binary-tree-paths
0450-delete-node-in-a-bst
0515-find-largest-value-in-each-tree-row
0543-diameter-of-binary-tree
0653-two-sum-iv-input-is-a-bst
0896-smallest-subtree-with-all-the-deepest-nodes
1029-vertical-order-traversal-of-a-binary-tree
1050-construct-binary-search-tree-from-preorder-traversal
1093-recover-a-tree-from-preorder-traversal
1218-lowest-common-ancestor-of-deepest-leaves
1387-find-elements-in-a-contaminated-binary-tree
2780-make-costs-of-paths-equal-in-a-binary-tree

Binary Tree

0098-validate-binary-search-tree
0100-same-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0110-balanced-binary-tree
0124-binary-tree-maximum-path-sum
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0173-binary-search-tree-iterator
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0257-binary-tree-paths
0450-delete-node-in-a-bst
0515-find-largest-value-in-each-tree-row
0543-diameter-of-binary-tree
0653-two-sum-iv-input-is-a-bst
0896-smallest-subtree-with-all-the-deepest-nodes
1029-vertical-order-traversal-of-a-binary-tree
1050-construct-binary-search-tree-from-preorder-traversal
1093-recover-a-tree-from-preorder-traversal
1218-lowest-common-ancestor-of-deepest-leaves
1387-find-elements-in-a-contaminated-binary-tree
2780-make-costs-of-paths-equal-in-a-binary-tree

Memoization

0070-climbing-stairs

Combinatorics

0062-unique-paths
1993-sum-of-all-subset-xor-totals
3548-find-the-count-of-good-integers

Binary Search Tree

0098-validate-binary-search-tree
0173-binary-search-tree-iterator
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0450-delete-node-in-a-bst
0653-two-sum-iv-input-is-a-bst
1050-construct-binary-search-tree-from-preorder-traversal

Design

0173-binary-search-tree-iterator
1387-find-elements-in-a-contaminated-binary-tree
2434-design-a-number-container-system

Iterator

0173-binary-search-tree-iterator

Bucket Sort

0451-sort-characters-by-frequency

Quickselect

0215-kth-largest-element-in-an-array

Database

0176-second-highest-salary
0180-consecutive-numbers
0181-employees-earning-more-than-their-managers
0183-customers-who-never-order
0184-department-highest-salary
0197-rising-temperature
1153-product-sales-analysis-i
1179-game-play-analysis-i
1509-replace-employee-id-with-the-unique-identifier
1724-customer-who-visited-but-did-not-make-any-transactions

Ordered Set

2434-design-a-number-container-system

Concurrency

1187-print-foobar-alternately

Topological Sort

2090-number-of-ways-to-arrive-at-destination

Enumeration

1993-sum-of-all-subset-xor-totals
2998-count-symmetric-integers
3548-find-the-count-of-good-integers