LeetCode-Multiverse

Collection of LeetCode questions & solutions.

LeetCode Topics

Array

0001-two-sum
0004-median-of-two-sorted-arrays
0011-container-with-most-water
0015-3sum
0026-remove-duplicates-from-sorted-array
0027-remove-element
0031-next-permutation
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0036-valid-sudoku
0039-combination-sum
0041-first-missing-positive
0042-trapping-rain-water
0045-jump-game-ii
0046-permutations
0048-rotate-image
0049-group-anagrams
0051-n-queens
0053-maximum-subarray
0054-spiral-matrix
0055-jump-game
0056-merge-intervals
0057-insert-interval
0063-unique-paths-ii
0064-minimum-path-sum
0066-plus-one
0068-text-justification
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0075-sort-colors
0078-subsets
0079-word-search
0080-remove-duplicates-from-sorted-array-ii
0084-largest-rectangle-in-histogram
0088-merge-sorted-array
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0108-convert-sorted-array-to-binary-search-tree
0118-pascals-triangle
0120-triangle
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0123-best-time-to-buy-and-sell-stock-iii
0128-longest-consecutive-sequence
0130-surrounded-regions
0134-gas-station
0135-candy
0136-single-number
0137-single-number-ii
0139-word-break
0149-max-points-on-a-line
0150-evaluate-reverse-polish-notation
0152-maximum-product-subarray
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0169-majority-element
0188-best-time-to-buy-and-sell-stock-iv
0189-rotate-array
0198-house-robber
0200-number-of-islands
0209-minimum-size-subarray-sum
0212-word-search-ii
0215-kth-largest-element-in-an-array
0219-contains-duplicate-ii
0221-maximal-square
0228-summary-ranges
0238-product-of-array-except-self
0239-sliding-window-maximum
0240-search-a-2d-matrix-ii
0274-h-index
0283-move-zeroes
0287-find-the-duplicate-number
0289-game-of-life
0300-longest-increasing-subsequence
0303-range-sum-query-immutable
0307-range-sum-query-mutable
0322-coin-change
0334-increasing-triplet-subsequence
0347-top-k-frequent-elements
0373-find-k-pairs-with-smallest-sums
0380-insert-delete-getrandom-o1
0399-evaluate-division
0416-partition-equal-subset-sum
0452-minimum-number-of-arrows-to-burst-balloons
0502-ipo
0560-subarray-sum-equals-k
0605-can-place-flowers
0643-maximum-average-subarray-i
0724-find-pivot-index
0739-daily-temperatures
0772-construct-quad-tree
0945-snakes-and-ladders
0954-maximum-sum-circular-subarray
1036-rotting-oranges
1046-max-consecutive-ones-iii
1305-number-of-visible-people-in-a-queue
1319-unique-number-of-occurrences
1392-find-the-difference-of-two-arrays
1438-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit
1483-rank-teams-by-votes
1528-kids-with-the-greatest-number-of-candies
1586-longest-subarray-of-1s-after-deleting-one-element
1798-max-number-of-k-sum-pairs
1833-find-the-highest-altitude
1878-check-if-array-is-sorted-and-rotated
2102-find-the-middle-index-in-array
2428-equal-row-and-column-pairs
3820-number-of-unique-xor-triplets-ii
3824-number-of-unique-xor-triplets-i
3846-minimum-operations-to-make-array-sum-divisible-by-k

Dynamic Programming

0005-longest-palindromic-substring
0022-generate-parentheses
0032-longest-valid-parentheses
0042-trapping-rain-water
0045-jump-game-ii
0053-maximum-subarray
0055-jump-game
0062-unique-paths
0063-unique-paths-ii
0064-minimum-path-sum
0070-climbing-stairs
0072-edit-distance
0097-interleaving-string
0118-pascals-triangle
0120-triangle
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0123-best-time-to-buy-and-sell-stock-iii
0124-binary-tree-maximum-path-sum
0131-palindrome-partitioning
0139-word-break
0152-maximum-product-subarray
0188-best-time-to-buy-and-sell-stock-iv
0198-house-robber
0221-maximal-square
0279-perfect-squares
0300-longest-increasing-subsequence
0322-coin-change
0392-is-subsequence
0416-partition-equal-subset-sum
0954-maximum-sum-circular-subarray
1236-n-th-tribonacci-number
1250-longest-common-subsequence
1586-longest-subarray-of-1s-after-deleting-one-element

Greedy

0011-container-with-most-water
0045-jump-game-ii
0055-jump-game
0122-best-time-to-buy-and-sell-stock-ii
0134-gas-station
0135-candy
0334-increasing-triplet-subsequence
0452-minimum-number-of-arrows-to-burst-balloons
0502-ipo
0605-can-place-flowers
0768-partition-labels

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0012-integer-to-roman
0013-roman-to-integer
0017-letter-combinations-of-a-phone-number
0030-substring-with-concatenation-of-all-words
0036-valid-sudoku
0041-first-missing-positive
0049-group-anagrams
0073-set-matrix-zeroes
0076-minimum-window-substring
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0127-word-ladder
0128-longest-consecutive-sequence
0133-clone-graph
0138-copy-list-with-random-pointer
0139-word-break
0141-linked-list-cycle
0142-linked-list-cycle-ii
0146-lru-cache
0149-max-points-on-a-line
0160-intersection-of-two-linked-lists
0169-majority-element
0202-happy-number
0205-isomorphic-strings
0208-implement-trie-prefix-tree
0219-contains-duplicate-ii
0242-valid-anagram
0290-word-pattern
0347-top-k-frequent-elements
0380-insert-delete-getrandom-o1
0383-ransom-note
0387-first-unique-character-in-a-string
0432-all-oone-data-structure
0433-minimum-genetic-mutation
0438-find-all-anagrams-in-a-string
0560-subarray-sum-equals-k
0768-partition-labels
1319-unique-number-of-occurrences
1392-find-the-difference-of-two-arrays
1483-rank-teams-by-votes
1798-max-number-of-k-sum-pairs
2428-equal-row-and-column-pairs

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
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0108-convert-sorted-array-to-binary-search-tree
0148-sort-list
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
0772-construct-quad-tree
0954-maximum-sum-circular-subarray

Sorting

0015-3sum
0049-group-anagrams
0056-merge-intervals
0075-sort-colors
0088-merge-sorted-array
0148-sort-list
0169-majority-element
0215-kth-largest-element-in-an-array
0242-valid-anagram
0274-h-index
0295-find-median-from-data-stream
0347-top-k-frequent-elements
0452-minimum-number-of-arrows-to-burst-balloons
0502-ipo
1483-rank-teams-by-votes
1798-max-number-of-k-sum-pairs

Counting

0169-majority-element
0347-top-k-frequent-elements
0383-ransom-note
0387-first-unique-character-in-a-string
1483-rank-teams-by-votes

Math

0002-add-two-numbers
0009-palindrome-number
0012-integer-to-roman
0013-roman-to-integer
0048-rotate-image
0050-powx-n
0062-unique-paths
0066-plus-one
0067-add-binary
0069-sqrtx
0070-climbing-stairs
0149-max-points-on-a-line
0150-evaluate-reverse-polish-notation
0172-factorial-trailing-zeroes
0189-rotate-array
0202-happy-number
0224-basic-calculator
0279-perfect-squares
0380-insert-delete-getrandom-o1
1146-greatest-common-divisor-of-strings
1236-n-th-tribonacci-number
3820-number-of-unique-xor-triplets-ii
3824-number-of-unique-xor-triplets-i
3846-minimum-operations-to-make-array-sum-divisible-by-k

Two Pointers

0005-longest-palindromic-substring
0011-container-with-most-water
0015-3sum
0019-remove-nth-node-from-end-of-list
0026-remove-duplicates-from-sorted-array
0027-remove-element
0028-find-the-index-of-the-first-occurrence-in-a-string
0031-next-permutation
0042-trapping-rain-water
0061-rotate-list
0075-sort-colors
0080-remove-duplicates-from-sorted-array-ii
0082-remove-duplicates-from-sorted-list-ii
0086-partition-list
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
0167-two-sum-ii-input-array-is-sorted
0189-rotate-array
0202-happy-number
0234-palindrome-linked-list
0283-move-zeroes
0287-find-the-duplicate-number
0295-find-median-from-data-stream
0345-reverse-vowels-of-a-string
0392-is-subsequence
0443-string-compression
0768-partition-labels
1798-max-number-of-k-sum-pairs
1894-merge-strings-alternately

Counting Sort

0274-h-index

Design

0146-lru-cache
0155-min-stack
0173-binary-search-tree-iterator
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0295-find-median-from-data-stream
0303-range-sum-query-immutable
0307-range-sum-query-mutable
0380-insert-delete-getrandom-o1
0432-all-oone-data-structure
0969-number-of-recent-calls

Randomized

0380-insert-delete-getrandom-o1

Prefix Sum

0209-minimum-size-subarray-sum
0238-product-of-array-except-self
0303-range-sum-query-immutable
0560-subarray-sum-equals-k
0724-find-pivot-index
1046-max-consecutive-ones-iii
1833-find-the-highest-altitude
2102-find-the-middle-index-in-array

Stack

0020-valid-parentheses
0032-longest-valid-parentheses
0042-trapping-rain-water
0071-simplify-path
0084-largest-rectangle-in-histogram
0094-binary-tree-inorder-traversal
0114-flatten-binary-tree-to-linked-list
0150-evaluate-reverse-polish-notation
0155-min-stack
0173-binary-search-tree-iterator
0224-basic-calculator
0234-palindrome-linked-list
0394-decode-string
0739-daily-temperatures
1305-number-of-visible-people-in-a-queue

Monotonic Stack

0042-trapping-rain-water
0084-largest-rectangle-in-histogram
0739-daily-temperatures
1305-number-of-visible-people-in-a-queue

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0006-zigzag-conversion
0012-integer-to-roman
0013-roman-to-integer
0014-longest-common-prefix
0017-letter-combinations-of-a-phone-number
0020-valid-parentheses
0022-generate-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string
0030-substring-with-concatenation-of-all-words
0032-longest-valid-parentheses
0049-group-anagrams
0058-length-of-last-word
0067-add-binary
0068-text-justification
0071-simplify-path
0072-edit-distance
0076-minimum-window-substring
0079-word-search
0097-interleaving-string
0125-valid-palindrome
0127-word-ladder
0131-palindrome-partitioning
0139-word-break
0151-reverse-words-in-a-string
0205-isomorphic-strings
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0212-word-search-ii
0224-basic-calculator
0242-valid-anagram
0290-word-pattern
0345-reverse-vowels-of-a-string
0383-ransom-note
0387-first-unique-character-in-a-string
0392-is-subsequence
0394-decode-string
0399-evaluate-division
0433-minimum-genetic-mutation
0438-find-all-anagrams-in-a-string
0443-string-compression
0768-partition-labels
1146-greatest-common-divisor-of-strings
1250-longest-common-subsequence
1483-rank-teams-by-votes
1567-maximum-number-of-vowels-in-a-substring-of-given-length
1894-merge-strings-alternately

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

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string

Simulation

0054-spiral-matrix
0067-add-binary
0068-text-justification
0289-game-of-life
2428-equal-row-and-column-pairs

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
0035-search-insert-position
0069-sqrtx
0074-search-a-2d-matrix
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0209-minimum-size-subarray-sum
0222-count-complete-tree-nodes
0240-search-a-2d-matrix-ii
0287-find-the-duplicate-number
0300-longest-increasing-subsequence
1046-max-consecutive-ones-iii

Sliding Window

0003-longest-substring-without-repeating-characters
0030-substring-with-concatenation-of-all-words
0076-minimum-window-substring
0209-minimum-size-subarray-sum
0219-contains-duplicate-ii
0239-sliding-window-maximum
0438-find-all-anagrams-in-a-string
0643-maximum-average-subarray-i
1046-max-consecutive-ones-iii
1438-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit
1567-maximum-number-of-vowels-in-a-substring-of-given-length
1586-longest-subarray-of-1s-after-deleting-one-element

Matrix

0036-valid-sudoku
0048-rotate-image
0054-spiral-matrix
0063-unique-paths-ii
0064-minimum-path-sum
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0079-word-search
0130-surrounded-regions
0200-number-of-islands
0212-word-search-ii
0221-maximal-square
0240-search-a-2d-matrix-ii
0289-game-of-life
0772-construct-quad-tree
0945-snakes-and-ladders
1036-rotting-oranges
2428-equal-row-and-column-pairs

Union Find

0128-longest-consecutive-sequence
0130-surrounded-regions
0200-number-of-islands
0399-evaluate-division

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0024-swap-nodes-in-pairs
0025-reverse-nodes-in-k-group
0050-powx-n
0206-reverse-linked-list
0224-basic-calculator
0234-palindrome-linked-list
0394-decode-string

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0023-merge-k-sorted-lists
0024-swap-nodes-in-pairs
0025-reverse-nodes-in-k-group
0061-rotate-list
0082-remove-duplicates-from-sorted-list-ii
0083-remove-duplicates-from-sorted-list
0086-partition-list
0092-reverse-linked-list-ii
0114-flatten-binary-tree-to-linked-list
0117-populating-next-right-pointers-in-each-node-ii
0138-copy-list-with-random-pointer
0141-linked-list-cycle
0142-linked-list-cycle-ii
0146-lru-cache
0148-sort-list
0160-intersection-of-two-linked-lists
0206-reverse-linked-list
0234-palindrome-linked-list
0328-odd-even-linked-list
0432-all-oone-data-structure
0725-split-linked-list-in-parts

Doubly-Linked List

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

Tree

0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0100-same-tree
0101-symmetric-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0108-convert-sorted-array-to-binary-search-tree
0112-path-sum
0114-flatten-binary-tree-to-linked-list
0117-populating-next-right-pointers-in-each-node-ii
0124-binary-tree-maximum-path-sum
0129-sum-root-to-leaf-numbers
0173-binary-search-tree-iterator
0199-binary-tree-right-side-view
0222-count-complete-tree-nodes
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0236-lowest-common-ancestor-of-a-binary-tree
0437-path-sum-iii
0450-delete-node-in-a-bst
0530-minimum-absolute-difference-in-bst
0543-diameter-of-binary-tree
0637-average-of-levels-in-binary-tree
0772-construct-quad-tree
0904-leaf-similar-trees

Depth-First Search

0079-word-search
0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0112-path-sum
0114-flatten-binary-tree-to-linked-list
0117-populating-next-right-pointers-in-each-node-ii
0124-binary-tree-maximum-path-sum
0129-sum-root-to-leaf-numbers
0130-surrounded-regions
0133-clone-graph
0199-binary-tree-right-side-view
0200-number-of-islands
0207-course-schedule
0210-course-schedule-ii
0211-design-add-and-search-words-data-structure
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0236-lowest-common-ancestor-of-a-binary-tree
0399-evaluate-division
0437-path-sum-iii
0530-minimum-absolute-difference-in-bst
0543-diameter-of-binary-tree
0637-average-of-levels-in-binary-tree
0904-leaf-similar-trees

Breadth-First Search

0100-same-tree
0101-symmetric-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0112-path-sum
0117-populating-next-right-pointers-in-each-node-ii
0127-word-ladder
0130-surrounded-regions
0133-clone-graph
0199-binary-tree-right-side-view
0200-number-of-islands
0207-course-schedule
0210-course-schedule-ii
0226-invert-binary-tree
0279-perfect-squares
0322-coin-change
0399-evaluate-division
0433-minimum-genetic-mutation
0530-minimum-absolute-difference-in-bst
0637-average-of-levels-in-binary-tree
0945-snakes-and-ladders
1036-rotting-oranges

Binary Tree

0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0100-same-tree
0101-symmetric-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0108-convert-sorted-array-to-binary-search-tree
0112-path-sum
0114-flatten-binary-tree-to-linked-list
0117-populating-next-right-pointers-in-each-node-ii
0124-binary-tree-maximum-path-sum
0129-sum-root-to-leaf-numbers
0173-binary-search-tree-iterator
0199-binary-tree-right-side-view
0222-count-complete-tree-nodes
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0236-lowest-common-ancestor-of-a-binary-tree
0437-path-sum-iii
0450-delete-node-in-a-bst
0530-minimum-absolute-difference-in-bst
0543-diameter-of-binary-tree
0637-average-of-levels-in-binary-tree
0904-leaf-similar-trees

Binary Search Tree

0098-validate-binary-search-tree
0108-convert-sorted-array-to-binary-search-tree
0173-binary-search-tree-iterator
0230-kth-smallest-element-in-a-bst
0450-delete-node-in-a-bst
0530-minimum-absolute-difference-in-bst

Iterator

0173-binary-search-tree-iterator

Bit Manipulation

0067-add-binary
0078-subsets
0136-single-number
0137-single-number-ii
0190-reverse-bits
0191-number-of-1-bits
0201-bitwise-and-of-numbers-range
0222-count-complete-tree-nodes
0287-find-the-duplicate-number
3820-number-of-unique-xor-triplets-ii
3824-number-of-unique-xor-triplets-i

Graph

0133-clone-graph
0207-course-schedule
0210-course-schedule-ii
0399-evaluate-division

Shortest Path

0399-evaluate-division

Topological Sort

0207-course-schedule
0210-course-schedule-ii

Backtracking

0017-letter-combinations-of-a-phone-number
0022-generate-parentheses
0039-combination-sum
0046-permutations
0051-n-queens
0052-n-queens-ii
0077-combinations
0078-subsets
0079-word-search
0131-palindrome-partitioning
0212-word-search-ii

Merge Sort

0023-merge-k-sorted-lists
0148-sort-list

Heap (Priority Queue)

0023-merge-k-sorted-lists
0215-kth-largest-element-in-an-array
0239-sliding-window-maximum
0295-find-median-from-data-stream
0347-top-k-frequent-elements
0373-find-k-pairs-with-smallest-sums
0502-ipo
1438-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit

Queue

0239-sliding-window-maximum
0387-first-unique-character-in-a-string
0954-maximum-sum-circular-subarray
0969-number-of-recent-calls
1438-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit

Monotonic Queue

0239-sliding-window-maximum
0954-maximum-sum-circular-subarray
1438-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit

Quickselect

0215-kth-largest-element-in-an-array
0347-top-k-frequent-elements

Data Stream

0295-find-median-from-data-stream
0969-number-of-recent-calls

Geometry

0149-max-points-on-a-line

Memoization

0070-climbing-stairs
0139-word-break
1236-n-th-tribonacci-number

Combinatorics

0062-unique-paths

Database

0175-combine-two-tables
0584-find-customer-referee
1908-recyclable-and-low-fat-products

Bucket Sort

0347-top-k-frequent-elements

Enumeration

3820-number-of-unique-xor-triplets-ii

Binary Indexed Tree

0307-range-sum-query-mutable

Segment Tree

0307-range-sum-query-mutable

Ordered Set

1438-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit

Concurrency

1187-print-foobar-alternately
1216-print-zero-even-odd