LeetCode

Collection of LeetCode questions to ace the coding interview! - Created using LeetHub

Array

0001-two-sum
0011-container-with-most-water
0015-3sum
0036-valid-sudoku
0042-trapping-rain-water
0045-jump-game-ii
0048-rotate-image
0049-group-anagrams
0054-spiral-matrix
0056-merge-intervals
0057-insert-interval
0068-text-justification
0073-set-matrix-zeroes
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0128-longest-consecutive-sequence
0130-surrounded-regions
0134-gas-station
0135-candy
0150-evaluate-reverse-polish-notation
0167-two-sum-ii-input-array-is-sorted
0200-number-of-islands
0209-minimum-size-subarray-sum
0219-contains-duplicate-ii
0228-summary-ranges
0238-product-of-array-except-self
0274-h-index
0380-insert-delete-getrandom-o1
0399-evaluate-division
0452-minimum-number-of-arrows-to-burst-balloons

Dynamic Programming

0042-trapping-rain-water
0045-jump-game-ii
0124-binary-tree-maximum-path-sum
0392-is-subsequence

Greedy

0011-container-with-most-water
0045-jump-game-ii
0134-gas-station
0135-candy
0452-minimum-number-of-arrows-to-burst-balloons

Sorting

0015-3sum
0049-group-anagrams
0056-merge-intervals
0242-valid-anagram
0274-h-index
0452-minimum-number-of-arrows-to-burst-balloons

Counting Sort

0274-h-index
0383-ransom-note

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0012-integer-to-roman
0013-roman-to-integer
0030-substring-with-concatenation-of-all-words
0036-valid-sudoku
0049-group-anagrams
0073-set-matrix-zeroes
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0128-longest-consecutive-sequence
0133-clone-graph
0138-copy-list-with-random-pointer
0141-linked-list-cycle
0146-lru-cache
0202-happy-number
0205-isomorphic-strings
0219-contains-duplicate-ii
0242-valid-anagram
0290-word-pattern
0380-insert-delete-getrandom-o1
0383-ransom-note

Math

0002-add-two-numbers
0012-integer-to-roman
0013-roman-to-integer
0048-rotate-image
0150-evaluate-reverse-polish-notation
0202-happy-number
0224-basic-calculator
0380-insert-delete-getrandom-o1

Design

0146-lru-cache
0155-min-stack
0173-binary-search-tree-iterator
0380-insert-delete-getrandom-o1

Randomized

0380-insert-delete-getrandom-o1

Prefix Sum

0209-minimum-size-subarray-sum
0238-product-of-array-except-self

Two Pointers

0011-container-with-most-water
0015-3sum
0019-remove-nth-node-from-end-of-list
0028-find-the-index-of-the-first-occurrence-in-a-string
0042-trapping-rain-water
0061-rotate-list
0082-remove-duplicates-from-sorted-list-ii
0086-partition-list
0125-valid-palindrome
0141-linked-list-cycle
0151-reverse-words-in-a-string
0167-two-sum-ii-input-array-is-sorted
0202-happy-number
0392-is-subsequence

String

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

String Matching

0003-longest-substring-without-repeating-characters
0006-zigzag-conversion
0012-integer-to-roman
0013-roman-to-integer
0014-longest-common-prefix
0020-valid-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string
0030-substring-with-concatenation-of-all-words
0049-group-anagrams
0058-length-of-last-word
0068-text-justification
0071-simplify-path
0125-valid-palindrome
0151-reverse-words-in-a-string
0205-isomorphic-strings
0224-basic-calculator
0242-valid-anagram
0290-word-pattern
0383-ransom-note
0392-is-subsequence
0399-evaluate-division

Stack

0020-valid-parentheses
0042-trapping-rain-water
0071-simplify-path
0114-flatten-binary-tree-to-linked-list
0150-evaluate-reverse-polish-notation
0155-min-stack
0173-binary-search-tree-iterator
0224-basic-calculator

Monotonic Stack

0042-trapping-rain-water

Trie

0014-longest-common-prefix

Binary Search

0167-two-sum-ii-input-array-is-sorted
0209-minimum-size-subarray-sum

Sliding Window

0003-longest-substring-without-repeating-characters
0030-substring-with-concatenation-of-all-words
0209-minimum-size-subarray-sum
0219-contains-duplicate-ii

Matrix

0036-valid-sudoku
0048-rotate-image
0054-spiral-matrix
0073-set-matrix-zeroes
0130-surrounded-regions
0200-number-of-islands

Simulation

0054-spiral-matrix
0068-text-justification

Union Find

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

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
0082-remove-duplicates-from-sorted-list-ii
0086-partition-list
0092-reverse-linked-list-ii
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0138-copy-list-with-random-pointer
0141-linked-list-cycle
0146-lru-cache

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0025-reverse-nodes-in-k-group
0224-basic-calculator

Tree

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
0112-path-sum
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
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
0530-minimum-absolute-difference-in-bst
0637-average-of-levels-in-binary-tree

Depth-First Search

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
0116-populating-next-right-pointers-in-each-node
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
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0236-lowest-common-ancestor-of-a-binary-tree
0399-evaluate-division
0530-minimum-absolute-difference-in-bst
0637-average-of-levels-in-binary-tree

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
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
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
0399-evaluate-division
0530-minimum-absolute-difference-in-bst
0637-average-of-levels-in-binary-tree

Binary Tree

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
0112-path-sum
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
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
0530-minimum-absolute-difference-in-bst
0637-average-of-levels-in-binary-tree

Doubly-Linked List

0146-lru-cache

Divide and Conquer

0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal

Binary Search Tree

0098-validate-binary-search-tree
0173-binary-search-tree-iterator
0222-count-complete-tree-nodes
0230-kth-smallest-element-in-a-bst
0530-minimum-absolute-difference-in-bst

Iterator

0173-binary-search-tree-iterator

Bit Manipulation

0222-count-complete-tree-nodes

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

LeetCode Topics

Array

0001-two-sum
0004-median-of-two-sorted-arrays
0011-container-with-most-water
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0039-combination-sum
0042-trapping-rain-water
0045-jump-game-ii
0046-permutations
0047-permutations-ii
0053-maximum-subarray
0055-jump-game
0056-merge-intervals
0057-insert-interval
0063-unique-paths-ii
0064-minimum-path-sum
0066-plus-one
0074-search-a-2d-matrix
0079-word-search
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
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
0136-single-number
0137-single-number-ii
0139-word-break
0149-max-points-on-a-line
0153-find-minimum-in-rotated-sorted-array
0154-find-minimum-in-rotated-sorted-array-ii
0162-find-peak-element
0188-best-time-to-buy-and-sell-stock-iv
0198-house-robber
0212-word-search-ii
0213-house-robber-ii
0215-kth-largest-element-in-an-array
0216-combination-sum-iii
0221-maximal-square
0238-product-of-array-except-self
0275-h-index-ii
0283-move-zeroes
0300-longest-increasing-subsequence
0322-coin-change
0334-increasing-triplet-subsequence
0354-russian-doll-envelopes
0373-find-k-pairs-with-smallest-sums
0377-combination-sum-iv
0399-evaluate-division
0435-non-overlapping-intervals
0436-find-right-interval
0452-minimum-number-of-arrows-to-burst-balloons
0474-ones-and-zeroes
0495-teemo-attacking
0496-next-greater-element-i
0502-ipo
0503-next-greater-element-ii
0518-coin-change-ii
0540-single-element-in-a-sorted-array
0605-can-place-flowers
0611-valid-triangle-number
0643-maximum-average-subarray-i
0658-find-k-closest-elements
0673-number-of-longest-increasing-subsequence
0682-baseball-game
0714-best-time-to-buy-and-sell-stock-with-transaction-fee
0724-find-pivot-index
0735-asteroid-collision
0739-daily-temperatures
0740-delete-and-earn
0745-find-smallest-letter-greater-than-target
0747-min-cost-climbing-stairs
0772-construct-quad-tree
0792-binary-search
0882-peak-index-in-a-mountain-array
0907-koko-eating-bananas
0940-fruit-into-baskets
0945-snakes-and-ladders
0954-maximum-sum-circular-subarray
0967-minimum-falling-path-sum
1025-minimum-cost-for-tickets
1036-rotting-oranges
1046-max-consecutive-ones-iii
1087-longest-arithmetic-subsequence
1105-uncrossed-lines
1249-snapshot-array
1293-three-consecutive-odds
1319-unique-number-of-occurrences
1330-longest-arithmetic-subsequence-of-given-difference
1392-find-the-difference-of-two-arrays
1397-search-suggestions-system
1458-sort-integers-by-the-number-of-1-bits
1476-count-negative-numbers-in-a-sorted-matrix
1528-kids-with-the-greatest-number-of-candies
1586-longest-subarray-of-1s-after-deleting-one-element
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1646-kth-missing-positive-number
1798-max-number-of-k-sum-pairs
1833-find-the-highest-altitude
2038-nearest-exit-from-entrance-in-maze
2040-minimum-cost-to-reach-destination-in-time
2392-successful-pairs-of-spells-and-potions
2428-equal-row-and-column-pairs
2478-longest-nice-subarray
2553-total-cost-to-hire-k-workers
2626-count-the-number-of-good-subarrays
2636-maximum-subsequence-score
3171-minimum-equal-sum-of-two-arrays-after-replacing-zeros
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii

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
0107-binary-tree-level-order-traversal-ii
0111-minimum-depth-of-binary-tree
0112-path-sum
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0127-word-ladder
0133-clone-graph
0199-binary-tree-right-side-view
0207-course-schedule
0226-invert-binary-tree
0279-perfect-squares
0322-coin-change
0399-evaluate-division
0433-minimum-genetic-mutation
0617-merge-two-binary-trees
0774-maximum-depth-of-n-ary-tree
0801-is-graph-bipartite
0871-keys-and-rooms
0945-snakes-and-ladders
1036-rotting-oranges
1116-maximum-level-sum-of-a-binary-tree
1544-count-good-nodes-in-binary-tree
1576-reorder-routes-to-make-all-paths-lead-to-the-city-zero
2038-nearest-exit-from-entrance-in-maze

Matrix

0063-unique-paths-ii
0064-minimum-path-sum
0074-search-a-2d-matrix
0079-word-search
0212-word-search-ii
0221-maximal-square
0772-construct-quad-tree
0945-snakes-and-ladders
0967-minimum-falling-path-sum
1036-rotting-oranges
1476-count-negative-numbers-in-a-sorted-matrix
2038-nearest-exit-from-entrance-in-maze
2428-equal-row-and-column-pairs
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii

Hash Table

0001-two-sum
0017-letter-combinations-of-a-phone-number
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0127-word-ladder
0133-clone-graph
0139-word-break
0141-linked-list-cycle
0149-max-points-on-a-line
0208-implement-trie-prefix-tree
0424-longest-repeating-character-replacement
0433-minimum-genetic-mutation
0496-next-greater-element-i
0726-number-of-atoms
0740-delete-and-earn
0940-fruit-into-baskets
1023-time-based-key-value-store
1087-longest-arithmetic-subsequence
1249-snapshot-array
1319-unique-number-of-occurrences
1330-longest-arithmetic-subsequence-of-given-difference
1392-find-the-difference-of-two-arrays
1777-determine-if-two-strings-are-close
1798-max-number-of-k-sum-pairs
2413-smallest-number-in-infinite-set
2428-equal-row-and-column-pairs
2487-optimal-partition-of-string
2626-count-the-number-of-good-subarrays
3630-total-characters-in-string-after-transformations-ii

String

0005-longest-palindromic-substring
0017-letter-combinations-of-a-phone-number
0022-generate-parentheses
0032-longest-valid-parentheses
0043-multiply-strings
0067-add-binary
0072-edit-distance
0079-word-search
0097-interleaving-string
0115-distinct-subsequences
0127-word-ladder
0139-word-break
0151-reverse-words-in-a-string
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0212-word-search-ii
0257-binary-tree-paths
0345-reverse-vowels-of-a-string
0394-decode-string
0399-evaluate-division
0424-longest-repeating-character-replacement
0433-minimum-genetic-mutation
0443-string-compression
0474-ones-and-zeroes
0516-longest-palindromic-subsequence
0649-dota2-senate
0712-minimum-ascii-delete-sum-for-two-strings
0726-number-of-atoms
1023-time-based-key-value-store
1146-greatest-common-divisor-of-strings
1250-longest-common-subsequence
1320-remove-all-adjacent-duplicates-in-string-ii
1397-search-suggestions-system
1567-maximum-number-of-vowels-in-a-substring-of-given-length
1777-determine-if-two-strings-are-close
1894-merge-strings-alternately
2470-removing-stars-from-a-string
2487-optimal-partition-of-string
3630-total-characters-in-string-after-transformations-ii

Design

0173-binary-search-tree-iterator
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0937-online-stock-span
0969-number-of-recent-calls
1023-time-based-key-value-store
1249-snapshot-array
2413-smallest-number-in-infinite-set

Trie

0139-word-break
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0212-word-search-ii
1397-search-suggestions-system

Depth-First Search

0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0099-recover-binary-search-tree
0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0110-balanced-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0113-path-sum-ii
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0124-binary-tree-maximum-path-sum
0129-sum-root-to-leaf-numbers
0133-clone-graph
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0199-binary-tree-right-side-view
0207-course-schedule
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
0236-lowest-common-ancestor-of-a-binary-tree
0257-binary-tree-paths
0399-evaluate-division
0437-path-sum-iii
0543-diameter-of-binary-tree
0572-subtree-of-another-tree
0617-merge-two-binary-trees
0774-maximum-depth-of-n-ary-tree
0801-is-graph-bipartite
0871-keys-and-rooms
0904-leaf-similar-trees
1116-maximum-level-sum-of-a-binary-tree
1474-longest-zigzag-path-in-a-binary-tree
1544-count-good-nodes-in-binary-tree
1576-reorder-routes-to-make-all-paths-lead-to-the-city-zero

Backtracking

0017-letter-combinations-of-a-phone-number
0022-generate-parentheses
0039-combination-sum
0046-permutations
0047-permutations-ii
0052-n-queens-ii
0077-combinations
0079-word-search
0095-unique-binary-search-trees-ii
0113-path-sum-ii
0212-word-search-ii
0216-combination-sum-iii
0257-binary-tree-paths

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
0095-unique-binary-search-trees-ii
0096-unique-binary-search-trees
0097-interleaving-string
0115-distinct-subsequences
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
0139-word-break
0188-best-time-to-buy-and-sell-stock-iv
0198-house-robber
0213-house-robber-ii
0221-maximal-square
0279-perfect-squares
0300-longest-increasing-subsequence
0322-coin-change
0338-counting-bits
0354-russian-doll-envelopes
0377-combination-sum-iv
0435-non-overlapping-intervals
0458-poor-pigs
0474-ones-and-zeroes
0516-longest-palindromic-subsequence
0518-coin-change-ii
0673-number-of-longest-increasing-subsequence
0712-minimum-ascii-delete-sum-for-two-strings
0714-best-time-to-buy-and-sell-stock-with-transaction-fee
0740-delete-and-earn
0747-min-cost-climbing-stairs
0806-domino-and-tromino-tiling
0954-maximum-sum-circular-subarray
0956-number-of-music-playlists
0967-minimum-falling-path-sum
1013-fibonacci-number
1025-minimum-cost-for-tickets
1087-longest-arithmetic-subsequence
1105-uncrossed-lines
1236-n-th-tribonacci-number
1250-longest-common-subsequence
1330-longest-arithmetic-subsequence-of-given-difference
1474-longest-zigzag-path-in-a-binary-tree
1586-longest-subarray-of-1s-after-deleting-one-element
2040-minimum-cost-to-reach-destination-in-time
3630-total-characters-in-string-after-transformations-ii

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
0190-reverse-bits
0191-number-of-1-bits
0215-kth-largest-element-in-an-array
0772-construct-quad-tree
0954-maximum-sum-circular-subarray

Tree

0094-binary-tree-inorder-traversal
0095-unique-binary-search-trees-ii
0096-unique-binary-search-trees
0098-validate-binary-search-tree
0099-recover-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
0107-binary-tree-level-order-traversal-ii
0108-convert-sorted-array-to-binary-search-tree
0110-balanced-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0113-path-sum-ii
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0124-binary-tree-maximum-path-sum
0129-sum-root-to-leaf-numbers
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
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
0235-lowest-common-ancestor-of-a-binary-search-tree
0236-lowest-common-ancestor-of-a-binary-tree
0257-binary-tree-paths
0437-path-sum-iii
0450-delete-node-in-a-bst
0543-diameter-of-binary-tree
0572-subtree-of-another-tree
0617-merge-two-binary-trees
0772-construct-quad-tree
0774-maximum-depth-of-n-ary-tree
0783-search-in-a-binary-search-tree
0904-leaf-similar-trees
1116-maximum-level-sum-of-a-binary-tree
1474-longest-zigzag-path-in-a-binary-tree
1544-count-good-nodes-in-binary-tree

Binary Search Tree

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
0095-unique-binary-search-trees-ii
0096-unique-binary-search-trees
0098-validate-binary-search-tree
0099-recover-binary-search-tree
0108-convert-sorted-array-to-binary-search-tree
0153-find-minimum-in-rotated-sorted-array
0154-find-minimum-in-rotated-sorted-array-ii
0162-find-peak-element
0173-binary-search-tree-iterator
0222-count-complete-tree-nodes
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0275-h-index-ii
0278-first-bad-version
0300-longest-increasing-subsequence
0354-russian-doll-envelopes
0367-valid-perfect-square
0374-guess-number-higher-or-lower
0436-find-right-interval
0441-arranging-coins
0450-delete-node-in-a-bst
0540-single-element-in-a-sorted-array
0611-valid-triangle-number
0658-find-k-closest-elements
0745-find-smallest-letter-greater-than-target
0783-search-in-a-binary-search-tree
0792-binary-search
0882-peak-index-in-a-mountain-array
0907-koko-eating-bananas
1023-time-based-key-value-store
1046-max-consecutive-ones-iii
1087-longest-arithmetic-subsequence
1249-snapshot-array
1397-search-suggestions-system
1476-count-negative-numbers-in-a-sorted-matrix
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1646-kth-missing-positive-number
2392-successful-pairs-of-spells-and-potions

Binary Tree

0094-binary-tree-inorder-traversal
0095-unique-binary-search-trees-ii
0096-unique-binary-search-trees
0098-validate-binary-search-tree
0099-recover-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
0107-binary-tree-level-order-traversal-ii
0108-convert-sorted-array-to-binary-search-tree
0110-balanced-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0113-path-sum-ii
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0124-binary-tree-maximum-path-sum
0129-sum-root-to-leaf-numbers
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
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
0235-lowest-common-ancestor-of-a-binary-search-tree
0236-lowest-common-ancestor-of-a-binary-tree
0257-binary-tree-paths
0437-path-sum-iii
0450-delete-node-in-a-bst
0543-diameter-of-binary-tree
0572-subtree-of-another-tree
0617-merge-two-binary-trees
0783-search-in-a-binary-search-tree
0904-leaf-similar-trees
1116-maximum-level-sum-of-a-binary-tree
1474-longest-zigzag-path-in-a-binary-tree
1544-count-good-nodes-in-binary-tree

Linked List

0002-add-two-numbers
0023-merge-k-sorted-lists
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0141-linked-list-cycle
0143-reorder-list
0148-sort-list
0206-reverse-linked-list
0234-palindrome-linked-list
0328-odd-even-linked-list
2216-delete-the-middle-node-of-a-linked-list
2236-maximum-twin-sum-of-a-linked-list

Two Pointers

0005-longest-palindromic-substring
0011-container-with-most-water
0042-trapping-rain-water
0141-linked-list-cycle
0143-reorder-list
0148-sort-list
0151-reverse-words-in-a-string
0234-palindrome-linked-list
0283-move-zeroes
0345-reverse-vowels-of-a-string
0443-string-compression
0611-valid-triangle-number
0658-find-k-closest-elements
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1798-max-number-of-k-sum-pairs
1894-merge-strings-alternately
2216-delete-the-middle-node-of-a-linked-list
2236-maximum-twin-sum-of-a-linked-list
2392-successful-pairs-of-spells-and-potions
2553-total-cost-to-hire-k-workers

Sorting

0047-permutations-ii
0056-merge-intervals
0148-sort-list
0215-kth-largest-element-in-an-array
0354-russian-doll-envelopes
0435-non-overlapping-intervals
0436-find-right-interval
0452-minimum-number-of-arrows-to-burst-balloons
0502-ipo
0611-valid-triangle-number
0658-find-k-closest-elements
0726-number-of-atoms
1397-search-suggestions-system
1458-sort-integers-by-the-number-of-1-bits
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1777-determine-if-two-strings-are-close
1798-max-number-of-k-sum-pairs
2392-successful-pairs-of-spells-and-potions
2636-maximum-subsequence-score

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
0373-find-k-pairs-with-smallest-sums
0502-ipo
0658-find-k-closest-elements
1397-search-suggestions-system
2413-smallest-number-in-infinite-set
2553-total-cost-to-hire-k-workers
2636-maximum-subsequence-score
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii

Queue

0649-dota2-senate
0954-maximum-sum-circular-subarray
0969-number-of-recent-calls

Monotonic Queue

0954-maximum-sum-circular-subarray

Quickselect

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

Greedy

0011-container-with-most-water
0045-jump-game-ii
0055-jump-game
0122-best-time-to-buy-and-sell-stock-ii
0334-increasing-triplet-subsequence
0435-non-overlapping-intervals
0452-minimum-number-of-arrows-to-burst-balloons
0502-ipo
0605-can-place-flowers
0611-valid-triangle-number
0649-dota2-senate
0714-best-time-to-buy-and-sell-stock-with-transaction-fee
2487-optimal-partition-of-string
2636-maximum-subsequence-score
3171-minimum-equal-sum-of-two-arrays-after-replacing-zeros

Math

0002-add-two-numbers
0009-palindrome-number
0043-multiply-strings
0050-powx-n
0062-unique-paths
0066-plus-one
0067-add-binary
0069-sqrtx
0070-climbing-stairs
0096-unique-binary-search-trees
0149-max-points-on-a-line
0172-factorial-trailing-zeroes
0279-perfect-squares
0367-valid-perfect-square
0441-arranging-coins
0458-poor-pigs
0504-base-7
0956-number-of-music-playlists
1013-fibonacci-number
1146-greatest-common-divisor-of-strings
1236-n-th-tribonacci-number
1585-the-kth-factor-of-n
3630-total-characters-in-string-after-transformations-ii

Bit Manipulation

0067-add-binary
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
0338-counting-bits
1441-minimum-flips-to-make-a-or-b-equal-to-c
1458-sort-integers-by-the-number-of-1-bits
2478-longest-nice-subarray

Simulation

0043-multiply-strings
0067-add-binary
0495-teemo-attacking
0682-baseball-game
0735-asteroid-collision
2428-equal-row-and-column-pairs
2470-removing-stars-from-a-string
2553-total-cost-to-hire-k-workers

Geometry

0149-max-points-on-a-line

Recursion

0002-add-two-numbers
0050-powx-n
0143-reorder-list
0206-reverse-linked-list
0234-palindrome-linked-list
0394-decode-string
1013-fibonacci-number

Memoization

0070-climbing-stairs
0139-word-break
1013-fibonacci-number
1236-n-th-tribonacci-number

Stack

0032-longest-valid-parentheses
0042-trapping-rain-water
0094-binary-tree-inorder-traversal
0114-flatten-binary-tree-to-linked-list
0143-reorder-list
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0173-binary-search-tree-iterator
0234-palindrome-linked-list
0394-decode-string
0496-next-greater-element-i
0503-next-greater-element-ii
0682-baseball-game
0726-number-of-atoms
0735-asteroid-collision
0739-daily-temperatures
0937-online-stock-span
1320-remove-all-adjacent-duplicates-in-string-ii
2236-maximum-twin-sum-of-a-linked-list
2470-removing-stars-from-a-string

Combinatorics

0062-unique-paths
0458-poor-pigs
0956-number-of-music-playlists

Counting

1458-sort-integers-by-the-number-of-1-bits
1777-determine-if-two-strings-are-close
3630-total-characters-in-string-after-transformations-ii

Binary Indexed Tree

0673-number-of-longest-increasing-subsequence

Segment Tree

0673-number-of-longest-increasing-subsequence

Number Theory

1585-the-kth-factor-of-n

Sliding Window

0424-longest-repeating-character-replacement
0643-maximum-average-subarray-i
0658-find-k-closest-elements
0940-fruit-into-baskets
1046-max-consecutive-ones-iii
1567-maximum-number-of-vowels-in-a-substring-of-given-length
1586-longest-subarray-of-1s-after-deleting-one-element
2478-longest-nice-subarray
2626-count-the-number-of-good-subarrays

Monotonic Stack

0042-trapping-rain-water
0496-next-greater-element-i
0503-next-greater-element-ii
0739-daily-temperatures
0937-online-stock-span

Graph

0133-clone-graph
0207-course-schedule
0399-evaluate-division
0801-is-graph-bipartite
0871-keys-and-rooms
1576-reorder-routes-to-make-all-paths-lead-to-the-city-zero
2040-minimum-cost-to-reach-destination-in-time
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii

Topological Sort

0207-course-schedule

Union Find

0399-evaluate-division
0801-is-graph-bipartite

Prefix Sum

0238-product-of-array-except-self
0724-find-pivot-index
1046-max-consecutive-ones-iii
1833-find-the-highest-altitude

Data Stream

0937-online-stock-span
0969-number-of-recent-calls

Shortest Path

0399-evaluate-division
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii

Ordered Set

2413-smallest-number-in-infinite-set

Interactive

0278-first-bad-version
0374-guess-number-higher-or-lower

Iterator

0173-binary-search-tree-iterator

String Matching

0572-subtree-of-another-tree

Hash Function

0572-subtree-of-another-tree