LeetCode Topics

Array

0011-container-with-most-water
0026-remove-duplicates-from-sorted-array
0027-remove-element
0033-search-in-rotated-sorted-array
0036-valid-sudoku
0040-combination-sum-ii
0045-jump-game-ii
0046-permutations
0048-rotate-image
0049-group-anagrams
0053-maximum-subarray
0055-jump-game
0080-remove-duplicates-from-sorted-array-ii
0088-merge-sorted-array
0122-best-time-to-buy-and-sell-stock-ii
0136-single-number
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0169-majority-element
0189-rotate-array
0219-contains-duplicate-ii
0228-summary-ranges
0238-product-of-array-except-self
0253-meeting-rooms-ii
0287-find-the-duplicate-number
0289-game-of-life
0318-maximum-product-of-word-lengths
0346-moving-average-from-data-stream
0376-wiggle-subsequence
0455-assign-cookies
0542-01-matrix
0550-shortest-path-to-get-food
0630-course-schedule-iii
0646-maximum-length-of-pair-chain
0761-employee-free-time
1014-k-closest-points-to-origin
1019-squares-of-a-sorted-array
1036-rotting-oranges
1112-find-words-that-can-be-formed-by-characters
1149-intersection-of-three-sorted-arrays
1353-find-resultant-array-after-removing-anagrams
1426-find-n-unique-integers-sum-up-to-zero
1476-count-negative-numbers-in-a-sorted-matrix
1482-how-many-numbers-are-smaller-than-the-current-number
1483-rank-teams-by-votes
1547-destination-city
1802-number-of-students-unable-to-eat-lunch
1927-maximum-ascending-subarray-sum
2107-find-unique-binary-string
2137-final-value-of-variable-after-performing-operations
2169-simple-bank-system
2210-find-target-indices-after-sorting-array
2219-maximum-number-of-words-found-in-sentences
2308-divide-array-into-equal-pairs
2432-number-of-zero-filled-subarrays
2589-maximum-value-of-a-string-in-an-array
2624-difference-between-element-sum-and-digit-sum-of-an-array
2661-smallest-missing-non-negative-integer-after-operations
2668-form-smallest-number-from-two-digit-arrays
2881-split-strings-by-separator
3221-find-the-peaks
3242-count-elements-with-maximum-frequency
3309-count-prefix-and-suffix-pairs-i
3332-minimum-operations-to-exceed-threshold-value-ii
3383-taking-maximum-energy-from-the-mystic-dungeon
3397-find-the-integer-added-to-array-i
3501-delete-nodes-from-linked-list-present-in-array
3612-adjacent-increasing-subarrays-detection-i
3619-adjacent-increasing-subarrays-detection-ii
3708-zigzag-grid-traversal-with-skip
3790-fruits-into-baskets-ii
3827-implement-router

Binary Search

0033-search-in-rotated-sorted-array
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0270-closest-binary-search-tree-value
0287-find-the-duplicate-number
1149-intersection-of-three-sorted-arrays
1476-count-negative-numbers-in-a-sorted-matrix
2210-find-target-indices-after-sorting-array
3619-adjacent-increasing-subarrays-detection-ii
3790-fruits-into-baskets-ii
3827-implement-router

Matrix

0036-valid-sudoku
0048-rotate-image
0289-game-of-life
0542-01-matrix
0550-shortest-path-to-get-food
1036-rotting-oranges
1476-count-negative-numbers-in-a-sorted-matrix
3708-zigzag-grid-traversal-with-skip

Hash Table

0003-longest-substring-without-repeating-characters
0013-roman-to-integer
0036-valid-sudoku
0049-group-anagrams
0133-clone-graph
0141-linked-list-cycle
0169-majority-element
0219-contains-duplicate-ii
0359-logger-rate-limiter
0387-first-unique-character-in-a-string
0653-two-sum-iv-input-is-a-bst
0893-all-nodes-distance-k-in-binary-tree
0896-smallest-subtree-with-all-the-deepest-nodes
1112-find-words-that-can-be-formed-by-characters
1149-intersection-of-three-sorted-arrays
1264-maximum-number-of-words-you-can-type
1353-find-resultant-array-after-removing-anagrams
1482-how-many-numbers-are-smaller-than-the-current-number
1483-rank-teams-by-votes
1547-destination-city
2053-check-if-all-characters-have-equal-number-of-occurrences
2107-find-unique-binary-string
2169-simple-bank-system
2308-divide-array-into-equal-pairs
2620-find-consecutive-integers-from-a-data-stream
2661-smallest-missing-non-negative-integer-after-operations
2668-form-smallest-number-from-two-digit-arrays
3242-count-elements-with-maximum-frequency
3501-delete-nodes-from-linked-list-present-in-array
3753-maximum-difference-between-even-and-odd-frequency-i
3827-implement-router
3872-find-most-frequent-vowel-and-consonant

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0008-string-to-integer-atoi
0013-roman-to-integer
0028-find-the-index-of-the-first-occurrence-in-a-string
0038-count-and-say
0049-group-anagrams
0058-length-of-last-word
0067-add-binary
0151-reverse-words-in-a-string
0301-remove-invalid-parentheses
0316-remove-duplicate-letters
0318-maximum-product-of-word-lengths
0387-first-unique-character-in-a-string
0606-construct-string-from-binary-tree
0851-goat-latin
1112-find-words-that-can-be-formed-by-characters
1264-maximum-number-of-words-you-can-type
1353-find-resultant-array-after-removing-anagrams
1483-rank-teams-by-votes
1547-destination-city
1714-rearrange-spaces-between-words
1894-merge-strings-alternately
2053-check-if-all-characters-have-equal-number-of-occurrences
2076-sum-of-digits-of-string-after-convert
2107-find-unique-binary-string
2137-final-value-of-variable-after-performing-operations
2168-check-if-numbers-are-ascending-in-a-sentence
2217-step-by-step-directions-from-a-binary-tree-node-to-another
2219-maximum-number-of-words-found-in-sentences
2346-largest-3-same-digit-number-in-string
2589-maximum-value-of-a-string-in-an-array
2881-split-strings-by-separator
2887-sort-vowels-in-a-string
3309-count-prefix-and-suffix-pairs-i
3753-maximum-difference-between-even-and-odd-frequency-i
3768-check-if-digits-are-equal-in-string-after-operations-i
3872-find-most-frequent-vowel-and-consonant

Sorting

0049-group-anagrams
0088-merge-sorted-array
0169-majority-element
0253-meeting-rooms-ii
0455-assign-cookies
0630-course-schedule-iii
0646-maximum-length-of-pair-chain
0761-employee-free-time
1014-k-closest-points-to-origin
1019-squares-of-a-sorted-array
1353-find-resultant-array-after-removing-anagrams
1482-how-many-numbers-are-smaller-than-the-current-number
1483-rank-teams-by-votes
2210-find-target-indices-after-sorting-array
2887-sort-vowels-in-a-string

Dynamic Programming

0005-longest-palindromic-substring
0045-jump-game-ii
0053-maximum-subarray
0055-jump-game
0096-unique-binary-search-trees
0122-best-time-to-buy-and-sell-stock-ii
0376-wiggle-subsequence
0542-01-matrix
0646-maximum-length-of-pair-chain

Greedy

0011-container-with-most-water
0045-jump-game-ii
0055-jump-game
0122-best-time-to-buy-and-sell-stock-ii
0253-meeting-rooms-ii
0316-remove-duplicate-letters
0376-wiggle-subsequence
0455-assign-cookies
0630-course-schedule-iii
0646-maximum-length-of-pair-chain
2661-smallest-missing-non-negative-integer-after-operations

Math

0007-reverse-integer
0013-roman-to-integer
0048-rotate-image
0067-add-binary
0096-unique-binary-search-trees
0189-rotate-array
1014-k-closest-points-to-origin
1426-find-n-unique-integers-sum-up-to-zero
1817-calculate-money-in-leetcode-bank
2432-number-of-zero-filled-subarrays
2624-difference-between-element-sum-and-digit-sum-of-an-array
2661-smallest-missing-non-negative-integer-after-operations
3768-check-if-digits-are-equal-in-string-after-operations-i

Tree

0096-unique-binary-search-trees
0098-validate-binary-search-tree
0099-recover-binary-search-tree
0103-binary-tree-zigzag-level-order-traversal
0113-path-sum-ii
0199-binary-tree-right-side-view
0235-lowest-common-ancestor-of-a-binary-search-tree
0270-closest-binary-search-tree-value
0606-construct-string-from-binary-tree
0653-two-sum-iv-input-is-a-bst
0893-all-nodes-distance-k-in-binary-tree
0896-smallest-subtree-with-all-the-deepest-nodes
1254-deepest-leaves-sum
1484-linked-list-in-binary-tree
2217-step-by-step-directions-from-a-binary-tree-node-to-another

Binary Search Tree

0096-unique-binary-search-trees
0098-validate-binary-search-tree
0099-recover-binary-search-tree
0235-lowest-common-ancestor-of-a-binary-search-tree
0270-closest-binary-search-tree-value
0653-two-sum-iv-input-is-a-bst

Binary Tree

0096-unique-binary-search-trees
0098-validate-binary-search-tree
0099-recover-binary-search-tree
0103-binary-tree-zigzag-level-order-traversal
0113-path-sum-ii
0199-binary-tree-right-side-view
0235-lowest-common-ancestor-of-a-binary-search-tree
0270-closest-binary-search-tree-value
0606-construct-string-from-binary-tree
0653-two-sum-iv-input-is-a-bst
0893-all-nodes-distance-k-in-binary-tree
0896-smallest-subtree-with-all-the-deepest-nodes
1254-deepest-leaves-sum
1484-linked-list-in-binary-tree
2217-step-by-step-directions-from-a-binary-tree-node-to-another

Depth-First Search

0098-validate-binary-search-tree
0099-recover-binary-search-tree
0113-path-sum-ii
0133-clone-graph
0199-binary-tree-right-side-view
0207-course-schedule
0210-course-schedule-ii
0235-lowest-common-ancestor-of-a-binary-search-tree
0270-closest-binary-search-tree-value
0323-number-of-connected-components-in-an-undirected-graph
0606-construct-string-from-binary-tree
0653-two-sum-iv-input-is-a-bst
0893-all-nodes-distance-k-in-binary-tree
0896-smallest-subtree-with-all-the-deepest-nodes
1254-deepest-leaves-sum
1484-linked-list-in-binary-tree
1558-course-schedule-iv
2121-find-if-path-exists-in-graph
2217-step-by-step-directions-from-a-binary-tree-node-to-another

Breadth-First Search

0103-binary-tree-zigzag-level-order-traversal
0133-clone-graph
0199-binary-tree-right-side-view
0207-course-schedule
0210-course-schedule-ii
0301-remove-invalid-parentheses
0323-number-of-connected-components-in-an-undirected-graph
0542-01-matrix
0550-shortest-path-to-get-food
0653-two-sum-iv-input-is-a-bst
0893-all-nodes-distance-k-in-binary-tree
0896-smallest-subtree-with-all-the-deepest-nodes
1036-rotting-oranges
1254-deepest-leaves-sum
1558-course-schedule-iv
2121-find-if-path-exists-in-graph

Two Pointers

0005-longest-palindromic-substring
0011-container-with-most-water
0026-remove-duplicates-from-sorted-array
0027-remove-element
0028-find-the-index-of-the-first-occurrence-in-a-string
0080-remove-duplicates-from-sorted-array-ii
0088-merge-sorted-array
0141-linked-list-cycle
0151-reverse-words-in-a-string
0167-two-sum-ii-input-array-is-sorted
0189-rotate-array
0253-meeting-rooms-ii
0287-find-the-duplicate-number
0455-assign-cookies
0528-swapping-nodes-in-a-linked-list
0653-two-sum-iv-input-is-a-bst
1019-squares-of-a-sorted-array
1894-merge-strings-alternately

Bit Manipulation

0067-add-binary
0136-single-number
0287-find-the-duplicate-number
0318-maximum-product-of-word-lengths
2308-divide-array-into-equal-pairs

Simulation

0067-add-binary
0289-game-of-life
1802-number-of-students-unable-to-eat-lunch
2076-sum-of-digits-of-string-after-convert
2137-final-value-of-variable-after-performing-operations
2169-simple-bank-system
3332-minimum-operations-to-exceed-threshold-value-ii
3708-zigzag-grid-traversal-with-skip
3768-check-if-digits-are-equal-in-string-after-operations-i
3790-fruits-into-baskets-ii

Union Find

0323-number-of-connected-components-in-an-undirected-graph
2121-find-if-path-exists-in-graph

Graph

0133-clone-graph
0207-course-schedule
0210-course-schedule-ii
0323-number-of-connected-components-in-an-undirected-graph
1558-course-schedule-iv
2121-find-if-path-exists-in-graph

Queue

0232-implement-queue-using-stacks
0346-moving-average-from-data-stream
0387-first-unique-character-in-a-string
0969-number-of-recent-calls
1802-number-of-students-unable-to-eat-lunch
2620-find-consecutive-integers-from-a-data-stream
3827-implement-router

Counting

0169-majority-element
0387-first-unique-character-in-a-string
1112-find-words-that-can-be-formed-by-characters
1149-intersection-of-three-sorted-arrays
1482-how-many-numbers-are-smaller-than-the-current-number
1483-rank-teams-by-votes
2053-check-if-all-characters-have-equal-number-of-occurrences
2308-divide-array-into-equal-pairs
2620-find-consecutive-integers-from-a-data-stream
3242-count-elements-with-maximum-frequency
3753-maximum-difference-between-even-and-odd-frequency-i
3872-find-most-frequent-vowel-and-consonant

Design

0232-implement-queue-using-stacks
0346-moving-average-from-data-stream
0359-logger-rate-limiter
0937-online-stock-span
0969-number-of-recent-calls
2169-simple-bank-system
2620-find-consecutive-integers-from-a-data-stream
3827-implement-router

Data Stream

0346-moving-average-from-data-stream
0359-logger-rate-limiter
0937-online-stock-span
0969-number-of-recent-calls
2620-find-consecutive-integers-from-a-data-stream

Stack

0232-implement-queue-using-stacks
0316-remove-duplicate-letters
0937-online-stock-span
1802-number-of-students-unable-to-eat-lunch

Heap (Priority Queue)

0253-meeting-rooms-ii
0630-course-schedule-iii
0761-employee-free-time
1014-k-closest-points-to-origin
3332-minimum-operations-to-exceed-threshold-value-ii

Prefix Sum

0238-product-of-array-except-self
0253-meeting-rooms-ii
3383-taking-maximum-energy-from-the-mystic-dungeon

Topological Sort

0207-course-schedule
0210-course-schedule-ii
1558-course-schedule-iv

Divide and Conquer

0053-maximum-subarray
0169-majority-element
1014-k-closest-points-to-origin

Geometry

1014-k-closest-points-to-origin

Quickselect

1014-k-closest-points-to-origin

Linked List

0141-linked-list-cycle
0528-swapping-nodes-in-a-linked-list
1484-linked-list-in-binary-tree
1765-merge-in-between-linked-lists
3501-delete-nodes-from-linked-list-present-in-array

Sliding Window

0003-longest-substring-without-repeating-characters
0219-contains-duplicate-ii

Backtracking

0040-combination-sum-ii
0046-permutations
0113-path-sum-ii
0301-remove-invalid-parentheses
2107-find-unique-binary-string

Enumeration

2668-form-smallest-number-from-two-digit-arrays
3221-find-the-peaks

Trie

3309-count-prefix-and-suffix-pairs-i

Rolling Hash

3309-count-prefix-and-suffix-pairs-i

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string
3309-count-prefix-and-suffix-pairs-i

Hash Function

3309-count-prefix-and-suffix-pairs-i

Database

0175-combine-two-tables
0176-second-highest-salary
0177-nth-highest-salary
0178-rank-scores
0584-find-customer-referee
0595-big-countries
1153-product-sales-analysis-i
1258-article-views-i
1390-average-selling-price
1509-replace-employee-id-with-the-unique-identifier
1541-top-travellers
1625-group-sold-products-by-the-date
1801-average-time-of-process-per-machine
1827-invalid-tweets
1908-recyclable-and-low-fat-products
1948-rearrange-products-table

Segment Tree

3790-fruits-into-baskets-ii

Ordered Set

3790-fruits-into-baskets-ii
3827-implement-router

Monotonic Stack

0316-remove-duplicate-letters
0937-online-stock-span

Combinatorics

3768-check-if-digits-are-equal-in-string-after-operations-i

Number Theory

3768-check-if-digits-are-equal-in-string-after-operations-i