leetcode

A collection of LeetCode questions to ace the coding interview! - Created using LeetHub v2

LeetCode Topics

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
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
0112-path-sum
0113-path-sum-ii
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
0199-binary-tree-right-side-view
0222-count-complete-tree-nodes
0226-invert-binary-tree
0236-lowest-common-ancestor-of-a-binary-tree
0331-verify-preorder-serialization-of-a-binary-tree
0337-house-robber-iii
0530-minimum-absolute-difference-in-bst
2400-minimum-score-after-removals-on-a-tree

Breadth-First Search

0100-same-tree
0101-symmetric-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0107-binary-tree-level-order-traversal-ii
0112-path-sum
0116-populating-next-right-pointers-in-each-node
0126-word-ladder-ii
0127-word-ladder
0130-surrounded-regions
0199-binary-tree-right-side-view
0200-number-of-islands
0207-course-schedule
0226-invert-binary-tree
0279-perfect-squares
0301-remove-invalid-parentheses
0310-minimum-height-trees
0322-coin-change
0329-longest-increasing-path-in-a-matrix
0399-evaluate-division
0407-trapping-rain-water-ii
0417-pacific-atlantic-water-flow
0530-minimum-absolute-difference-in-bst
0542-01-matrix
0721-accounts-merge
0794-swim-in-rising-water
1036-rotting-oranges
1747-lexicographically-smallest-string-after-applying-operations

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
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
0112-path-sum
0113-path-sum-ii
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
0199-binary-tree-right-side-view
0222-count-complete-tree-nodes
0226-invert-binary-tree
0236-lowest-common-ancestor-of-a-binary-tree
0331-verify-preorder-serialization-of-a-binary-tree
0337-house-robber-iii
0530-minimum-absolute-difference-in-bst

String

0006-zigzag-conversion
0012-integer-to-roman
0013-roman-to-integer
0020-valid-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string
0058-length-of-last-word
0067-add-binary
0071-simplify-path
0072-edit-distance
0087-scramble-string
0091-decode-ways
0093-restore-ip-addresses
0097-interleaving-string
0125-valid-palindrome
0126-word-ladder-ii
0127-word-ladder
0140-word-break-ii
0151-reverse-words-in-a-string
0165-compare-version-numbers
0166-fraction-to-recurring-decimal
0179-largest-number
0187-repeated-dna-sequences
0205-isomorphic-strings
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0214-shortest-palindrome
0224-basic-calculator
0227-basic-calculator-ii
0242-valid-anagram
0273-integer-to-english-words
0282-expression-add-operators
0290-word-pattern
0299-bulls-and-cows
0301-remove-invalid-parentheses
0316-remove-duplicate-letters
0331-verify-preorder-serialization-of-a-binary-tree
0344-reverse-string
0345-reverse-vowels-of-a-string
0392-is-subsequence
0399-evaluate-division
0424-longest-repeating-character-replacement
0438-find-all-anagrams-in-a-string
0721-accounts-merge
1006-vowel-spellchecker
1250-longest-common-subsequence
1302-delete-characters-to-make-fancy-string
1350-remove-sub-folders-from-the-filesystem
1353-find-resultant-array-after-removing-anagrams
1747-lexicographically-smallest-string-after-applying-operations
1818-maximum-score-from-removing-substrings
2079-delete-duplicate-folders-in-system
2137-final-value-of-variable-after-performing-operations
2346-largest-3-same-digit-number-in-string
2429-design-a-food-rating-system
3396-valid-word
3617-find-the-original-typed-string-i
3618-find-the-original-typed-string-ii
3768-check-if-digits-are-equal-in-string-after-operations-i
3797-design-spreadsheet
3872-find-most-frequent-vowel-and-consonant

Dynamic Programming

0055-jump-game
0062-unique-paths
0064-minimum-path-sum
0070-climbing-stairs
0072-edit-distance
0087-scramble-string
0091-decode-ways
0095-unique-binary-search-trees-ii
0096-unique-binary-search-trees
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
0140-word-break-ii
0174-dungeon-game
0188-best-time-to-buy-and-sell-stock-iv
0198-house-robber
0233-number-of-digit-one
0264-ugly-number-ii
0279-perfect-squares
0300-longest-increasing-subsequence
0309-best-time-to-buy-and-sell-stock-with-cooldown
0312-burst-balloons
0313-super-ugly-number
0322-coin-change
0329-longest-increasing-path-in-a-matrix
0337-house-robber-iii
0338-counting-bits
0343-integer-break
0354-russian-doll-envelopes
0357-count-numbers-with-unique-digits
0392-is-subsequence
0416-partition-equal-subset-sum
0435-non-overlapping-intervals
0542-01-matrix
0826-soup-servings
0867-new-21-game
0934-bitwise-ors-of-subarrays
1111-minimum-score-triangulation-of-polygon
1250-longest-common-subsequence
1352-maximum-profit-in-job-scheduling
1402-count-square-submatrices-with-all-ones
1586-longest-subarray-of-1s-after-deleting-one-element
2267-minimum-difference-in-sums-after-removal-of-elements
2408-number-of-people-aware-of-a-secret
2882-ways-to-express-an-integer-as-sum-of-powers
3437-maximum-total-damage-with-spell-casting
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
3648-find-the-maximum-number-of-fruits-collected
3733-length-of-longest-v-shaped-diagonal-segment
3851-find-sum-of-array-product-of-magical-sequences

Depth-First Search

0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0099-recover-binary-search-tree
0100-same-tree
0101-symmetric-tree
0110-balanced-binary-tree
0112-path-sum
0113-path-sum-ii
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
0130-surrounded-regions
0199-binary-tree-right-side-view
0200-number-of-islands
0207-course-schedule
0211-design-add-and-search-words-data-structure
0226-invert-binary-tree
0236-lowest-common-ancestor-of-a-binary-tree
0310-minimum-height-trees
0329-longest-increasing-path-in-a-matrix
0337-house-robber-iii
0399-evaluate-division
0417-pacific-atlantic-water-flow
0530-minimum-absolute-difference-in-bst
0721-accounts-merge
0794-swim-in-rising-water
1350-remove-sub-folders-from-the-filesystem
1747-lexicographically-smallest-string-after-applying-operations
2400-minimum-score-after-removals-on-a-tree

Binary Search Tree

0004-median-of-two-sorted-arrays
0035-search-insert-position
0069-sqrtx
0074-search-a-2d-matrix
0081-search-in-rotated-sorted-array-ii
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
0154-find-minimum-in-rotated-sorted-array-ii
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0222-count-complete-tree-nodes
0240-search-a-2d-matrix-ii
0268-missing-number
0275-h-index-ii
0300-longest-increasing-subsequence
0315-count-of-smaller-numbers-after-self
0327-count-of-range-sum
0349-intersection-of-two-arrays
0352-data-stream-as-disjoint-intervals
0354-russian-doll-envelopes
0363-max-sum-of-rectangle-no-larger-than-k
0530-minimum-absolute-difference-in-bst
0611-valid-triangle-number
0794-swim-in-rising-water
1352-maximum-profit-in-job-scheduling
1612-avoid-flood-in-the-city
2392-successful-pairs-of-spells-and-potions
2498-smallest-subarrays-with-maximum-bitwise-or
3437-maximum-total-damage-with-spell-casting
3619-adjacent-increasing-subarrays-detection-ii
3640-maximum-frequency-of-an-element-after-performing-operations-ii
3791-fruits-into-baskets-iii
3827-implement-router
3902-maximize-spanning-tree-stability-with-upgrades

Array

0004-median-of-two-sorted-arrays
0011-container-with-most-water
0026-remove-duplicates-from-sorted-array
0027-remove-element
0035-search-insert-position
0037-sudoku-solver
0055-jump-game
0059-spiral-matrix-ii
0064-minimum-path-sum
0066-plus-one
0074-search-a-2d-matrix
0075-sort-colors
0078-subsets
0080-remove-duplicates-from-sorted-array-ii
0081-search-in-rotated-sorted-array-ii
0088-merge-sorted-array
0090-subsets-ii
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
0130-surrounded-regions
0134-gas-station
0135-candy
0136-single-number
0137-single-number-ii
0140-word-break-ii
0154-find-minimum-in-rotated-sorted-array-ii
0162-find-peak-element
0164-maximum-gap
0167-two-sum-ii-input-array-is-sorted
0169-majority-element
0174-dungeon-game
0179-largest-number
0188-best-time-to-buy-and-sell-stock-iv
0189-rotate-array
0198-house-robber
0200-number-of-islands
0204-count-primes
0216-combination-sum-iii
0217-contains-duplicate
0218-the-skyline-problem
0219-contains-duplicate-ii
0220-contains-duplicate-iii
0228-summary-ranges
0229-majority-element-ii
0238-product-of-array-except-self
0239-sliding-window-maximum
0240-search-a-2d-matrix-ii
0260-single-number-iii
0268-missing-number
0274-h-index
0275-h-index-ii
0289-game-of-life
0300-longest-increasing-subsequence
0303-range-sum-query-immutable
0304-range-sum-query-2d-immutable
0309-best-time-to-buy-and-sell-stock-with-cooldown
0312-burst-balloons
0313-super-ugly-number
0315-count-of-smaller-numbers-after-self
0321-create-maximum-number
0322-coin-change
0324-wiggle-sort-ii
0327-count-of-range-sum
0329-longest-increasing-path-in-a-matrix
0330-patching-array
0335-self-crossing
0347-top-k-frequent-elements
0349-intersection-of-two-arrays
0354-russian-doll-envelopes
0363-max-sum-of-rectangle-no-larger-than-k
0380-insert-delete-getrandom-o1
0399-evaluate-division
0407-trapping-rain-water-ii
0416-partition-equal-subset-sum
0417-pacific-atlantic-water-flow
0435-non-overlapping-intervals
0452-minimum-number-of-arrows-to-burst-balloons
0498-diagonal-traverse
0542-01-matrix
0611-valid-triangle-number
0621-task-scheduler
0679-24-game
0721-accounts-merge
0794-swim-in-rising-water
0830-largest-triangle-area
0934-bitwise-ors-of-subarrays
0940-fruit-into-baskets
1006-vowel-spellchecker
1018-largest-perimeter-triangle
1036-rotting-oranges
1111-minimum-score-triangulation-of-polygon
1350-remove-sub-folders-from-the-filesystem
1352-maximum-profit-in-job-scheduling
1353-find-resultant-array-after-removing-anagrams
1402-count-square-submatrices-with-all-ones
1510-find-lucky-integer-in-an-array
1586-longest-subarray-of-1s-after-deleting-one-element
1612-avoid-flood-in-the-city
1706-min-cost-to-connect-all-points
1834-minimum-number-of-people-to-teach
1917-maximum-average-pass-ratio
2023-design-movie-rental-system
2079-delete-duplicate-folders-in-system
2137-final-value-of-variable-after-performing-operations
2170-count-number-of-maximum-bitwise-or-subsets
2267-minimum-difference-in-sums-after-removal-of-elements
2307-replace-non-coprime-numbers-in-array
2316-count-hills-and-valleys-in-an-array
2324-find-triangular-sum-of-an-array
2392-successful-pairs-of-spells-and-potions
2400-minimum-score-after-removals-on-a-tree
2429-design-a-food-rating-system
2432-number-of-zero-filled-subarrays
2498-smallest-subarrays-with-maximum-bitwise-or
2503-longest-subarray-with-maximum-bitwise-and
2529-range-product-queries-of-powers
2661-smallest-missing-non-negative-integer-after-operations
3242-count-elements-with-maximum-frequency
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
3383-taking-maximum-energy-from-the-mystic-dungeon
3437-maximum-total-damage-with-spell-casting
3459-find-the-minimum-area-to-cover-all-ones-ii
3461-find-the-minimum-area-to-cover-all-ones-i
3490-find-the-maximum-length-of-valid-subsequence-i
3491-find-the-maximum-length-of-valid-subsequence-ii
3612-adjacent-increasing-subarrays-detection-i
3619-adjacent-increasing-subarrays-detection-ii
3620-maximum-number-of-distinct-elements-after-operations
3640-maximum-frequency-of-an-element-after-performing-operations-ii
3648-find-the-maximum-number-of-fruits-collected
3733-length-of-longest-v-shaped-diagonal-segment
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
3791-fruits-into-baskets-iii
3797-design-spreadsheet
3827-implement-router
3851-find-sum-of-array-product-of-magical-sequences

Hash Table

0012-integer-to-roman
0013-roman-to-integer
0037-sudoku-solver
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0126-word-ladder-ii
0127-word-ladder
0140-word-break-ii
0141-linked-list-cycle
0142-linked-list-cycle-ii
0166-fraction-to-recurring-decimal
0169-majority-element
0187-repeated-dna-sequences
0202-happy-number
0205-isomorphic-strings
0208-implement-trie-prefix-tree
0217-contains-duplicate
0219-contains-duplicate-ii
0229-majority-element-ii
0242-valid-anagram
0264-ugly-number-ii
0268-missing-number
0290-word-pattern
0299-bulls-and-cows
0347-top-k-frequent-elements
0349-intersection-of-two-arrays
0355-design-twitter
0380-insert-delete-getrandom-o1
0424-longest-repeating-character-replacement
0438-find-all-anagrams-in-a-string
0621-task-scheduler
0721-accounts-merge
0900-reordered-power-of-2
0940-fruit-into-baskets
1006-vowel-spellchecker
1353-find-resultant-array-after-removing-anagrams
1510-find-lucky-integer-in-an-array
1612-avoid-flood-in-the-city
1834-minimum-number-of-people-to-teach
2023-design-movie-rental-system
2079-delete-duplicate-folders-in-system
2429-design-a-food-rating-system
2661-smallest-missing-non-negative-integer-after-operations
3242-count-elements-with-maximum-frequency
3437-maximum-total-damage-with-spell-casting
3788-maximum-unique-subarray-sum-after-deletion
3797-design-spreadsheet
3827-implement-router
3872-find-most-frequent-vowel-and-consonant

Divide and Conquer

0004-median-of-two-sorted-arrays
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
0218-the-skyline-problem
0240-search-a-2d-matrix-ii
0315-count-of-smaller-numbers-after-self
0324-wiggle-sort-ii
0327-count-of-range-sum
0347-top-k-frequent-elements

Sorting

0075-sort-colors
0088-merge-sorted-array
0147-insertion-sort-list
0148-sort-list
0164-maximum-gap
0169-majority-element
0179-largest-number
0217-contains-duplicate
0220-contains-duplicate-iii
0229-majority-element-ii
0242-valid-anagram
0268-missing-number
0274-h-index
0324-wiggle-sort-ii
0347-top-k-frequent-elements
0349-intersection-of-two-arrays
0354-russian-doll-envelopes
0435-non-overlapping-intervals
0452-minimum-number-of-arrows-to-burst-balloons
0611-valid-triangle-number
0621-task-scheduler
0721-accounts-merge
0900-reordered-power-of-2
1018-largest-perimeter-triangle
1352-maximum-profit-in-job-scheduling
1353-find-resultant-array-after-removing-anagrams
1613-find-critical-and-pseudo-critical-edges-in-minimum-spanning-tree
2392-successful-pairs-of-spells-and-potions
3277-find-the-number-of-ways-to-place-people-ii
3278-find-the-number-of-ways-to-place-people-i
3437-maximum-total-damage-with-spell-casting
3620-maximum-number-of-distinct-elements-after-operations
3640-maximum-frequency-of-an-element-after-performing-operations-ii
3748-sort-matrix-by-diagonals

Heap (Priority Queue)

0218-the-skyline-problem
0239-sliding-window-maximum
0264-ugly-number-ii
0347-top-k-frequent-elements
0355-design-twitter
0407-trapping-rain-water-ii
0621-task-scheduler
0794-swim-in-rising-water
1612-avoid-flood-in-the-city
1917-maximum-average-pass-ratio
2023-design-movie-rental-system
2267-minimum-difference-in-sums-after-removal-of-elements
2429-design-a-food-rating-system

Bucket Sort

0164-maximum-gap
0220-contains-duplicate-iii
0347-top-k-frequent-elements

Counting

0169-majority-element
0229-majority-element-ii
0299-bulls-and-cows
0347-top-k-frequent-elements
0621-task-scheduler
0900-reordered-power-of-2
1510-find-lucky-integer-in-an-array
3242-count-elements-with-maximum-frequency
3437-maximum-total-damage-with-spell-casting
3872-find-most-frequent-vowel-and-consonant

Quickselect

0324-wiggle-sort-ii
0347-top-k-frequent-elements

Design

0155-min-stack
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0303-range-sum-query-immutable
0304-range-sum-query-2d-immutable
0352-data-stream-as-disjoint-intervals
0355-design-twitter
0380-insert-delete-getrandom-o1
2023-design-movie-rental-system
2429-design-a-food-rating-system
3797-design-spreadsheet
3827-implement-router

Trie

0140-word-break-ii
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
1350-remove-sub-folders-from-the-filesystem
2079-delete-duplicate-folders-in-system

Graph

0207-course-schedule
0310-minimum-height-trees
0329-longest-increasing-path-in-a-matrix
0399-evaluate-division
1613-find-critical-and-pseudo-critical-edges-in-minimum-spanning-tree
1706-min-cost-to-connect-all-points
3902-maximize-spanning-tree-stability-with-upgrades

Topological Sort

0207-course-schedule
0310-minimum-height-trees
0329-longest-increasing-path-in-a-matrix

Linked List

0002-add-two-numbers
0061-rotate-list
0086-partition-list
0092-reverse-linked-list-ii
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
0141-linked-list-cycle
0142-linked-list-cycle-ii
0147-insertion-sort-list
0148-sort-list
0203-remove-linked-list-elements
0206-reverse-linked-list
0237-delete-node-in-a-linked-list
0328-odd-even-linked-list
0355-design-twitter
1411-convert-binary-number-in-a-linked-list-to-integer

Math

0002-add-two-numbers
0009-palindrome-number
0012-integer-to-roman
0013-roman-to-integer
0062-unique-paths
0066-plus-one
0067-add-binary
0069-sqrtx
0070-climbing-stairs
0089-gray-code
0096-unique-binary-search-trees
0166-fraction-to-recurring-decimal
0189-rotate-array
0202-happy-number
0204-count-primes
0223-rectangle-area
0224-basic-calculator
0227-basic-calculator-ii
0231-power-of-two
0233-number-of-digit-one
0264-ugly-number-ii
0268-missing-number
0273-integer-to-english-words
0279-perfect-squares
0282-expression-add-operators
0292-nim-game
0313-super-ugly-number
0319-bulb-switcher
0326-power-of-three
0335-self-crossing
0342-power-of-four
0343-integer-break
0357-count-numbers-with-unique-digits
0380-insert-delete-getrandom-o1
0679-24-game
0826-soup-servings
0830-largest-triangle-area
0867-new-21-game
0900-reordered-power-of-2
0903-implement-rand10-using-rand7
0915-generate-random-point-in-a-circle
1018-largest-perimeter-triangle
1411-convert-binary-number-in-a-linked-list-to-integer
1440-convert-integer-to-the-sum-of-two-no-zero-integers
1448-maximum-69-number
2307-replace-non-coprime-numbers-in-array
2324-find-triangular-sum-of-an-array
2432-number-of-zero-filled-subarrays
2661-smallest-missing-non-negative-integer-after-operations
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
3336-water-bottles-ii
3600-find-the-k-th-character-in-string-game-i
3601-find-the-k-th-character-in-string-game-ii
3744-minimum-operations-to-make-array-elements-zero
3768-check-if-digits-are-equal-in-string-after-operations-i
3830-find-closest-person
3851-find-sum-of-array-product-of-magical-sequences

Union Find

0130-surrounded-regions
0200-number-of-islands
0399-evaluate-division
0721-accounts-merge
0794-swim-in-rising-water
1613-find-critical-and-pseudo-critical-edges-in-minimum-spanning-tree
1706-min-cost-to-connect-all-points
3902-maximize-spanning-tree-stability-with-upgrades

Matrix

0037-sudoku-solver
0059-spiral-matrix-ii
0064-minimum-path-sum
0074-search-a-2d-matrix
0130-surrounded-regions
0174-dungeon-game
0200-number-of-islands
0240-search-a-2d-matrix-ii
0289-game-of-life
0304-range-sum-query-2d-immutable
0329-longest-increasing-path-in-a-matrix
0363-max-sum-of-rectangle-no-larger-than-k
0407-trapping-rain-water-ii
0417-pacific-atlantic-water-flow
0498-diagonal-traverse
0542-01-matrix
0794-swim-in-rising-water
1036-rotting-oranges
1402-count-square-submatrices-with-all-ones
3459-find-the-minimum-area-to-cover-all-ones-ii
3461-find-the-minimum-area-to-cover-all-ones-i
3648-find-the-maximum-number-of-fruits-collected
3733-length-of-longest-v-shaped-diagonal-segment
3748-sort-matrix-by-diagonals
3797-design-spreadsheet

Combinatorics

0062-unique-paths
2324-find-triangular-sum-of-an-array
3768-check-if-digits-are-equal-in-string-after-operations-i
3851-find-sum-of-array-product-of-magical-sequences

Greedy

0011-container-with-most-water
0055-jump-game
0122-best-time-to-buy-and-sell-stock-ii
0134-gas-station
0135-candy
0179-largest-number
0316-remove-duplicate-letters
0321-create-maximum-number
0324-wiggle-sort-ii
0330-patching-array
0435-non-overlapping-intervals
0452-minimum-number-of-arrows-to-burst-balloons
0611-valid-triangle-number
0621-task-scheduler
1018-largest-perimeter-triangle
1448-maximum-69-number
1612-avoid-flood-in-the-city
1818-maximum-score-from-removing-substrings
1834-minimum-number-of-people-to-teach
1917-maximum-average-pass-ratio
2661-smallest-missing-non-negative-integer-after-operations
3620-maximum-number-of-distinct-elements-after-operations
3788-maximum-unique-subarray-sum-after-deletion
3902-maximize-spanning-tree-stability-with-upgrades

Sliding Window

0187-repeated-dna-sequences
0219-contains-duplicate-ii
0220-contains-duplicate-iii
0239-sliding-window-maximum
0424-longest-repeating-character-replacement
0438-find-all-anagrams-in-a-string
0867-new-21-game
0940-fruit-into-baskets
1586-longest-subarray-of-1s-after-deleting-one-element
2498-smallest-subarrays-with-maximum-bitwise-or
3640-maximum-frequency-of-an-element-after-performing-operations-ii

Two Pointers

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
0061-rotate-list
0075-sort-colors
0080-remove-duplicates-from-sorted-array-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
0165-compare-version-numbers
0167-two-sum-ii-input-array-is-sorted
0189-rotate-array
0202-happy-number
0321-create-maximum-number
0344-reverse-string
0345-reverse-vowels-of-a-string
0349-intersection-of-two-arrays
0392-is-subsequence
0611-valid-triangle-number
2392-successful-pairs-of-spells-and-potions
3437-maximum-total-damage-with-spell-casting

Bit Manipulation

0067-add-binary
0078-subsets
0089-gray-code
0090-subsets-ii
0136-single-number
0137-single-number-ii
0187-repeated-dna-sequences
0190-reverse-bits
0191-number-of-1-bits
0222-count-complete-tree-nodes
0231-power-of-two
0260-single-number-iii
0268-missing-number
0338-counting-bits
0342-power-of-four
0934-bitwise-ors-of-subarrays
2170-count-number-of-maximum-bitwise-or-subsets
2400-minimum-score-after-removals-on-a-tree
2498-smallest-subarrays-with-maximum-bitwise-or
2503-longest-subarray-with-maximum-bitwise-and
2529-range-product-queries-of-powers
2837-minimum-operations-to-make-the-integer-zero
3600-find-the-k-th-character-in-string-game-i
3601-find-the-k-th-character-in-string-game-ii
3744-minimum-operations-to-make-array-elements-zero
3851-find-sum-of-array-product-of-magical-sequences

Recursion

0002-add-two-numbers
0203-remove-linked-list-elements
0206-reverse-linked-list
0224-basic-calculator
0231-power-of-two
0233-number-of-digit-one
0273-integer-to-english-words
0326-power-of-three
0342-power-of-four
3600-find-the-k-th-character-in-string-game-i
3601-find-the-k-th-character-in-string-game-ii

Memoization

0070-climbing-stairs
0140-word-break-ii
0329-longest-increasing-path-in-a-matrix
3733-length-of-longest-v-shaped-diagonal-segment

Prefix Sum

0238-product-of-array-except-self
0303-range-sum-query-immutable
0304-range-sum-query-2d-immutable
0363-max-sum-of-rectangle-no-larger-than-k
2529-range-product-queries-of-powers
3383-taking-maximum-energy-from-the-mystic-dungeon
3618-find-the-original-typed-string-ii
3640-maximum-frequency-of-an-element-after-performing-operations-ii
3789-maximize-subarrays-after-removing-one-conflicting-pair

Simulation

0059-spiral-matrix-ii
0067-add-binary
0289-game-of-life
0498-diagonal-traverse
2137-final-value-of-variable-after-performing-operations
2324-find-triangular-sum-of-an-array
2408-number-of-people-aware-of-a-secret
3336-water-bottles-ii
3600-find-the-k-th-character-in-string-game-i
3768-check-if-digits-are-equal-in-string-after-operations-i

Stack

0020-valid-parentheses
0071-simplify-path
0094-binary-tree-inorder-traversal
0114-flatten-binary-tree-to-linked-list
0155-min-stack
0224-basic-calculator
0227-basic-calculator-ii
0316-remove-duplicate-letters
0321-create-maximum-number
0331-verify-preorder-serialization-of-a-binary-tree
1818-maximum-score-from-removing-substrings
2307-replace-non-coprime-numbers-in-array

Backtracking

0037-sudoku-solver
0078-subsets
0089-gray-code
0090-subsets-ii
0093-restore-ip-addresses
0095-unique-binary-search-trees-ii
0113-path-sum-ii
0126-word-ladder-ii
0140-word-break-ii
0216-combination-sum-iii
0282-expression-add-operators
0301-remove-invalid-parentheses
0357-count-numbers-with-unique-digits
0679-24-game
2170-count-number-of-maximum-bitwise-or-subsets

Hash Function

0187-repeated-dna-sequences
0214-shortest-palindrome
2079-delete-duplicate-folders-in-system

Counting Sort

0274-h-index

Segment Tree

0218-the-skyline-problem
0315-count-of-smaller-numbers-after-self
0327-count-of-range-sum
3789-maximize-subarrays-after-removing-one-conflicting-pair
3791-fruits-into-baskets-iii

Enumeration

0204-count-primes
0900-reordered-power-of-2
1747-lexicographically-smallest-string-after-applying-operations
2170-count-number-of-maximum-bitwise-or-subsets
2837-minimum-operations-to-make-the-integer-zero
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
3789-maximize-subarrays-after-removing-one-conflicting-pair

Merge Sort

0148-sort-list
0315-count-of-smaller-numbers-after-self
0327-count-of-range-sum

Radix Sort

0164-maximum-gap

Brainteaser

0292-nim-game
0319-bulb-switcher
2503-longest-subarray-with-maximum-bitwise-and
2837-minimum-operations-to-make-the-integer-zero

Database

0176-second-highest-salary
0177-nth-highest-salary

Number Theory

0204-count-primes
2307-replace-non-coprime-numbers-in-array
3768-check-if-digits-are-equal-in-string-after-operations-i

Rolling Hash

0187-repeated-dna-sequences
0214-shortest-palindrome

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string
0214-shortest-palindrome

Binary Indexed Tree

0218-the-skyline-problem
0315-count-of-smaller-numbers-after-self
0327-count-of-range-sum

Line Sweep

0218-the-skyline-problem

Ordered Set

0218-the-skyline-problem
0220-contains-duplicate-iii
0315-count-of-smaller-numbers-after-self
0327-count-of-range-sum
0352-data-stream-as-disjoint-intervals
0363-max-sum-of-rectangle-no-larger-than-k
2023-design-movie-rental-system
2429-design-a-food-rating-system
3791-fruits-into-baskets-iii
3827-implement-router

Geometry

0223-rectangle-area
0335-self-crossing
0830-largest-triangle-area
0915-generate-random-point-in-a-circle
3277-find-the-number-of-ways-to-place-people-ii
3278-find-the-number-of-ways-to-place-people-i

Queue

0239-sliding-window-maximum
2408-number-of-people-aware-of-a-secret
3827-implement-router

Monotonic Queue

0239-sliding-window-maximum

Game Theory

0292-nim-game

Monotonic Stack

0316-remove-duplicate-letters
0321-create-maximum-number

Probability and Statistics

0826-soup-servings
0867-new-21-game
0903-implement-rand10-using-rand7

Shortest Path

0399-evaluate-division

Randomized

0380-insert-delete-getrandom-o1
0903-implement-rand10-using-rand7
0915-generate-random-point-in-a-circle

Rejection Sampling

0903-implement-rand10-using-rand7
0915-generate-random-point-in-a-circle

Minimum Spanning Tree

1613-find-critical-and-pseudo-critical-edges-in-minimum-spanning-tree
1706-min-cost-to-connect-all-points
3902-maximize-spanning-tree-stability-with-upgrades

Strongly Connected Component

1613-find-critical-and-pseudo-critical-edges-in-minimum-spanning-tree

Bitmask

3851-find-sum-of-array-product-of-magical-sequences