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

LeetCode Topics

Array

0001-two-sum
0004-median-of-two-sorted-arrays
0015-3sum
0018-4sum
0026-remove-duplicates-from-sorted-array
0035-search-insert-position
0036-valid-sudoku
0039-combination-sum
0040-combination-sum-ii
0041-first-missing-positive
0042-trapping-rain-water
0046-permutations
0047-permutations-ii
0049-group-anagrams
0051-n-queens
0066-plus-one
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0075-sort-colors
0078-subsets
0079-word-search
0081-search-in-rotated-sorted-array-ii
0084-largest-rectangle-in-histogram
0088-merge-sorted-array
0090-subsets-ii
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0135-candy
0150-evaluate-reverse-polish-notation
0153-find-minimum-in-rotated-sorted-array
0167-two-sum-ii-input-array-is-sorted
0169-majority-element
0209-minimum-size-subarray-sum
0217-contains-duplicate
0219-contains-duplicate-ii
0228-summary-ranges
0229-majority-element-ii
0238-product-of-array-except-self
0239-sliding-window-maximum
0287-find-the-duplicate-number
0304-range-sum-query-2d-immutable
0347-top-k-frequent-elements
0407-trapping-rain-water-ii
0410-split-array-largest-sum
0416-partition-equal-subset-sum
0455-assign-cookies
0540-single-element-in-a-sorted-array
0560-subarray-sum-equals-k
0658-find-k-closest-elements
0679-24-game
0682-baseball-game
0735-asteroid-collision
0739-daily-temperatures
0792-binary-search
0797-rabbits-in-forest
0816-design-hashset
0817-design-hashmap
0854-making-a-large-island
0860-design-circular-queue
0882-peak-index-in-a-mountain-array
0883-car-fleet
0905-length-of-longest-fibonacci-subsequence
0907-koko-eating-bananas
0917-boats-to-save-people
0925-construct-binary-tree-from-preorder-and-postorder-traversal
0934-bitwise-ors-of-subarrays
0940-fruit-into-baskets
0945-snakes-and-ladders
0948-sort-an-array
0952-word-subsets
1049-minimum-domino-rotations-for-equal-row
1056-capacity-to-ship-packages-within-d-days
1145-number-of-submatrices-that-sum-to-target
1185-find-in-mountain-array
1227-number-of-equivalent-domino-pairs
1293-three-consecutive-odds
1335-maximum-candies-allocated-to-k-children
1364-tuple-with-same-product
1402-count-square-submatrices-with-all-ones
1407-group-the-people-given-the-group-size-they-belong-to
1421-find-numbers-with-even-number-of-digits
1424-maximum-candies-you-can-get-from-boxes
1477-product-of-the-last-k-numbers
1478-maximum-number-of-events-that-can-be-attended
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1510-find-lucky-integer-in-an-array
1524-string-matching-in-an-array
1586-longest-subarray-of-1s-after-deleting-one-element
1628-count-submatrices-with-all-ones
1631-number-of-sub-arrays-with-odd-sum
1656-count-good-triplets
1813-maximum-erasure-value
1819-construct-the-lexicographically-largest-valid-sequence
1849-maximum-absolute-sum-of-any-subarray
1851-maximum-number-of-events-that-can-be-attended-ii
1876-map-of-highest-peak
1878-check-if-array-is-sorted-and-rotated
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1927-maximum-ascending-subarray-sum
1993-sum-of-all-subset-xor-totals
2048-build-array-from-permutation
2058-concatenation-of-array
2099-number-of-strings-that-appear-as-substrings-in-word
2107-find-unique-binary-string
2145-grid-game
2160-minimum-operations-to-make-a-uni-value-grid
2170-count-number-of-maximum-bitwise-or-subsets
2180-maximum-number-of-tasks-you-can-assign
2215-finding-3-digit-even-numbers
2220-find-all-possible-recipes-from-given-supplies
2237-longest-palindrome-by-concatenating-two-letter-words
2249-count-the-hidden-sequences
2262-solving-questions-with-brainpower
2265-partition-array-according-to-given-pivot
2280-count-good-triplets-in-an-array
2292-counting-words-with-a-given-prefix
2308-divide-array-into-equal-pairs
2316-count-hills-and-valleys-in-an-array
2358-number-of-ways-to-split-array
2394-count-subarrays-with-score-less-than-k
2400-minimum-score-after-removals-on-a-tree
2432-number-of-zero-filled-subarrays
2448-count-number-of-bad-pairs
2465-shifting-letters-ii
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2478-longest-nice-subarray
2479-meeting-rooms-iii
2497-maximum-matching-of-players-with-trainers
2498-smallest-subarrays-with-maximum-bitwise-or
2527-count-subarrays-with-fixed-bounds
2533-bitwise-xor-of-all-pairings
2551-apply-operations-to-an-array
2564-most-profitable-path-in-a-tree
2588-maximum-number-of-points-from-grid-queries
2614-maximum-count-of-positive-integer-and-negative-integer
2665-minimum-time-to-repair-cars
2681-put-marbles-in-bags
2685-first-completely-painted-row-or-column
2690-house-robber-iv
2691-count-vowel-strings-in-ranges
2707-merge-two-2d-arrays-by-summing-values
2764-maximum-number-of-fish-in-a-grid
2766-find-the-prefix-common-array-of-two-arrays
2792-neighboring-bitwise-xor
2888-minimum-index-of-a-valid-split
2915-count-of-interesting-subarrays
3001-apply-operations-to-maximize-score
3142-longest-unequal-adjacent-groups-subsequence-ii
3152-maximum-value-of-an-ordered-triplet-ii
3154-maximum-value-of-an-ordered-triplet-i
3171-minimum-equal-sum-of-two-arrays-after-replacing-zeros
3194-find-words-containing-character
3213-count-subarrays-where-max-element-appears-at-least-k-times
3227-find-missing-and-repeated-values
3251-maximum-area-of-longest-diagonal-rectangle
3307-find-the-maximum-sum-of-node-values
3309-count-prefix-and-suffix-pairs-i
3321-type-of-triangle
3332-minimum-operations-to-exceed-threshold-value-ii
3348-minimum-cost-walk-in-weighted-graph
3372-longest-strictly-increasing-or-strictly-decreasing-subarray
3429-special-array-i
3430-count-days-without-meetings
3461-find-the-minimum-area-to-cover-all-ones-i
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3483-alternating-groups-ii
3490-find-the-maximum-length-of-valid-subsequence-i
3491-find-the-maximum-length-of-valid-subsequence-ii
3628-find-minimum-time-to-reach-last-room-ii
3643-zero-array-transformation-ii
3647-zero-array-transformation-iii
3648-find-the-maximum-number-of-fruits-collected
3656-minimum-number-of-operations-to-make-elements-in-array-distinct
3685-count-subarrays-of-length-three-with-a-condition
3705-find-the-largest-almost-missing-integer
3733-length-of-longest-v-shaped-diagonal-segment
3741-reschedule-meetings-for-maximum-free-time-ii
3743-reschedule-meetings-for-maximum-free-time-i
3748-sort-matrix-by-diagonals
3788-maximum-unique-subarray-sum-after-deletion
3789-maximize-subarrays-after-removing-one-conflicting-pair
3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii
3799-unique-3-digit-even-numbers
3819-count-covered-buildings

String

0003-longest-substring-without-repeating-characters
0014-longest-common-prefix
0020-valid-parentheses
0022-generate-parentheses
0038-count-and-say
0049-group-anagrams
0071-simplify-path
0076-minimum-window-substring
0079-word-search
0125-valid-palindrome
0131-palindrome-partitioning
0242-valid-anagram
0344-reverse-string
0394-decode-string
0424-longest-repeating-character-replacement
0557-reverse-words-in-a-string-iii
0567-permutation-in-string
0657-robot-return-to-origin
0680-valid-palindrome-ii
0768-partition-labels
0868-push-dominoes
0952-word-subsets
1023-time-based-key-value-store
1058-lexicographically-smallest-equivalent-string
1093-recover-a-tree-from-preorder-traversal
1160-letter-tile-possibilities
1170-shortest-common-supersequence
1302-delete-characters-to-make-fancy-string
1460-number-of-substrings-containing-all-three-characters
1502-construct-k-palindrome-strings
1516-the-k-th-lexicographical-string-of-all-happy-strings-of-length-n
1524-string-matching-in-an-array
1818-maximum-score-from-removing-substrings
1894-merge-strings-alternately
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1915-check-if-one-string-swap-can-make-strings-equal
2021-remove-all-occurrences-of-a-substring
2059-unique-length-3-palindromic-subsequences
2099-number-of-strings-that-appear-as-substrings-in-word
2107-find-unique-binary-string
2220-find-all-possible-recipes-from-given-supplies
2221-check-if-a-parentheses-string-can-be-valid
2237-longest-palindrome-by-concatenating-two-letter-words
2292-counting-words-with-a-given-prefix
2346-largest-3-same-digit-number-in-string
2456-construct-smallest-number-from-di-string
2463-minimum-recolors-to-get-k-consecutive-black-blocks
2465-shifting-letters-ii
2691-count-vowel-strings-in-ranges
3142-longest-unequal-adjacent-groups-subsequence-ii
3194-find-words-containing-character
3243-count-the-number-of-powerful-integers
3309-count-prefix-and-suffix-pairs-i
3396-valid-word
3445-lexicographically-minimum-string-after-removing-stars
3447-clear-digits
3455-minimum-length-of-string-after-operations
3569-count-of-substrings-containing-every-vowel-and-k-consonants-ii
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-ii
3637-count-number-of-balanced-permutations
3683-find-the-lexicographically-largest-string-from-the-box-i
3811-reverse-degree-of-a-string

Prefix Sum

0209-minimum-size-subarray-sum
0238-product-of-array-except-self
0304-range-sum-query-2d-immutable
0410-split-array-largest-sum
0560-subarray-sum-equals-k
1145-number-of-submatrices-that-sum-to-target
1477-product-of-the-last-k-numbers
1631-number-of-sub-arrays-with-odd-sum
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
2059-unique-length-3-palindromic-subsequences
2145-grid-game
2249-count-the-hidden-sequences
2358-number-of-ways-to-split-array
2394-count-subarrays-with-score-less-than-k
2465-shifting-letters-ii
2691-count-vowel-strings-in-ranges
2915-count-of-interesting-subarrays
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3643-zero-array-transformation-ii
3647-zero-array-transformation-iii
3789-maximize-subarrays-after-removing-one-conflicting-pair

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0036-valid-sudoku
0041-first-missing-positive
0049-group-anagrams
0073-set-matrix-zeroes
0076-minimum-window-substring
0138-copy-list-with-random-pointer
0146-lru-cache
0169-majority-element
0217-contains-duplicate
0219-contains-duplicate-ii
0229-majority-element-ii
0242-valid-anagram
0347-top-k-frequent-elements
0424-longest-repeating-character-replacement
0460-lfu-cache
0560-subarray-sum-equals-k
0567-permutation-in-string
0768-partition-labels
0797-rabbits-in-forest
0816-design-hashset
0817-design-hashmap
0900-reordered-power-of-2
0905-length-of-longest-fibonacci-subsequence
0925-construct-binary-tree-from-preorder-and-postorder-traversal
0931-maximum-frequency-stack
0940-fruit-into-baskets
0952-word-subsets
1023-time-based-key-value-store
1145-number-of-submatrices-that-sum-to-target
1160-letter-tile-possibilities
1218-lowest-common-ancestor-of-deepest-leaves
1227-number-of-equivalent-domino-pairs
1364-tuple-with-same-product
1387-find-elements-in-a-contaminated-binary-tree
1407-group-the-people-given-the-group-size-they-belong-to
1460-number-of-substrings-containing-all-three-characters
1500-count-largest-group
1502-construct-k-palindrome-strings
1510-find-lucky-integer-in-an-array
1813-maximum-erasure-value
1915-check-if-one-string-swap-can-make-strings-equal
1986-largest-color-value-in-a-directed-graph
2059-unique-length-3-palindromic-subsequences
2107-find-unique-binary-string
2215-finding-3-digit-even-numbers
2220-find-all-possible-recipes-from-given-supplies
2237-longest-palindrome-by-concatenating-two-letter-words
2308-divide-array-into-equal-pairs
2434-design-a-number-container-system
2448-count-number-of-bad-pairs
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2479-meeting-rooms-iii
2685-first-completely-painted-row-or-column
2707-merge-two-2d-arrays-by-summing-values
2766-find-the-prefix-common-array-of-two-arrays
2888-minimum-index-of-a-valid-split
2915-count-of-interesting-subarrays
3227-find-missing-and-repeated-values
3445-lexicographically-minimum-string-after-removing-stars
3455-minimum-length-of-string-after-operations
3548-find-the-count-of-good-integers
3569-count-of-substrings-containing-every-vowel-and-k-consonants-ii
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-ii
3656-minimum-number-of-operations-to-make-elements-in-array-distinct
3705-find-the-largest-almost-missing-integer
3788-maximum-unique-subarray-sum-after-deletion
3799-unique-3-digit-even-numbers
3819-count-covered-buildings

Bit Manipulation

0078-subsets
0090-subsets-ii
0191-number-of-1-bits
0222-count-complete-tree-nodes
0231-power-of-two
0287-find-the-duplicate-number
0934-bitwise-ors-of-subarrays
1993-sum-of-all-subset-xor-totals
2059-unique-length-3-palindromic-subsequences
2170-count-number-of-maximum-bitwise-or-subsets
2308-divide-array-into-equal-pairs
2400-minimum-score-after-removals-on-a-tree
2478-longest-nice-subarray
2498-smallest-subarrays-with-maximum-bitwise-or
2509-minimize-xor
2533-bitwise-xor-of-all-pairings
2766-find-the-prefix-common-array-of-two-arrays
2792-neighboring-bitwise-xor
3307-find-the-maximum-sum-of-node-values
3348-minimum-cost-walk-in-weighted-graph
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3601-find-the-k-th-character-in-string-game-ii

String Matching

1524-string-matching-in-an-array
2292-counting-words-with-a-given-prefix
3309-count-prefix-and-suffix-pairs-i

Trie

0014-longest-common-prefix
3309-count-prefix-and-suffix-pairs-i

Rolling Hash

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

Hash Function

0816-design-hashset
0817-design-hashmap
3309-count-prefix-and-suffix-pairs-i

Greedy

0122-best-time-to-buy-and-sell-stock-ii
0135-candy
0410-split-array-largest-sum
0455-assign-cookies
0680-valid-palindrome-ii
0768-partition-labels
0797-rabbits-in-forest
0917-boats-to-save-people
1049-minimum-domino-rotations-for-equal-row
1407-group-the-people-given-the-group-size-they-belong-to
1448-maximum-69-number
1478-maximum-number-of-events-that-can-be-attended
1502-construct-k-palindrome-strings
1818-maximum-score-from-removing-substrings
2180-maximum-number-of-tasks-you-can-assign
2221-check-if-a-parentheses-string-can-be-valid
2237-longest-palindrome-by-concatenating-two-letter-words
2456-construct-smallest-number-from-di-string
2497-maximum-matching-of-players-with-trainers
2509-minimize-xor
2681-put-marbles-in-bags
3001-apply-operations-to-maximize-score
3171-minimum-equal-sum-of-two-arrays-after-replacing-zeros
3307-find-the-maximum-sum-of-node-values
3445-lexicographically-minimum-string-after-removing-stars
3647-zero-array-transformation-iii
3741-reschedule-meetings-for-maximum-free-time-ii
3743-reschedule-meetings-for-maximum-free-time-i
3788-maximum-unique-subarray-sum-after-deletion

Counting

0169-majority-element
0229-majority-element-ii
0347-top-k-frequent-elements
0900-reordered-power-of-2
1160-letter-tile-possibilities
1227-number-of-equivalent-domino-pairs
1364-tuple-with-same-product
1502-construct-k-palindrome-strings
1510-find-lucky-integer-in-an-array
1915-check-if-one-string-swap-can-make-strings-equal
1986-largest-color-value-in-a-directed-graph
2237-longest-palindrome-by-concatenating-two-letter-words
2308-divide-array-into-equal-pairs
2448-count-number-of-bad-pairs
2614-maximum-count-of-positive-integer-and-negative-integer
3455-minimum-length-of-string-after-operations
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-ii

Stack

0020-valid-parentheses
0042-trapping-rain-water
0071-simplify-path
0084-largest-rectangle-in-histogram
0094-binary-tree-inorder-traversal
0143-reorder-list
0150-evaluate-reverse-polish-notation
0155-min-stack
0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0394-decode-string
0682-baseball-game
0735-asteroid-collision
0739-daily-temperatures
0883-car-fleet
0931-maximum-frequency-stack
0937-online-stock-span
1628-count-submatrices-with-all-ones
1818-maximum-score-from-removing-substrings
2021-remove-all-occurrences-of-a-substring
2221-check-if-a-parentheses-string-can-be-valid
2456-construct-smallest-number-from-di-string
3001-apply-operations-to-maximize-score
3445-lexicographically-minimum-string-after-removing-stars
3447-clear-digits

Brainteaser

2533-bitwise-xor-of-all-pairings

Breadth-First Search

0407-trapping-rain-water-ii
0684-redundant-connection
0854-making-a-large-island
0945-snakes-and-ladders
1218-lowest-common-ancestor-of-deepest-leaves
1387-find-elements-in-a-contaminated-binary-tree
1424-maximum-candies-you-can-get-from-boxes
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1876-map-of-highest-peak
2564-most-profitable-path-in-a-tree
2583-divide-nodes-into-the-maximum-number-of-groups
2588-maximum-number-of-points-from-grid-queries
2764-maximum-number-of-fish-in-a-grid
2793-count-the-number-of-complete-components
3633-maximize-the-number-of-target-nodes-after-connecting-trees-i
3645-maximize-the-number-of-target-nodes-after-connecting-trees-ii

Graph

0684-redundant-connection
1424-maximum-candies-you-can-get-from-boxes
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1986-largest-color-value-in-a-directed-graph
2090-number-of-ways-to-arrive-at-destination
2220-find-all-possible-recipes-from-given-supplies
2564-most-profitable-path-in-a-tree
2583-divide-nodes-into-the-maximum-number-of-groups
2793-count-the-number-of-complete-components
3348-minimum-cost-walk-in-weighted-graph
3628-find-minimum-time-to-reach-last-room-ii

Heap (Priority Queue)

0023-merge-k-sorted-lists
0239-sliding-window-maximum
0347-top-k-frequent-elements
0407-trapping-rain-water-ii
0658-find-k-closest-elements
0948-sort-an-array
1478-maximum-number-of-events-that-can-be-attended
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
2434-design-a-number-container-system
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2479-meeting-rooms-iii
2588-maximum-number-of-points-from-grid-queries
2681-put-marbles-in-bags
3332-minimum-operations-to-exceed-threshold-value-ii
3445-lexicographically-minimum-string-after-removing-stars
3628-find-minimum-time-to-reach-last-room-ii
3647-zero-array-transformation-iii

Matrix

0036-valid-sudoku
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0079-word-search
0304-range-sum-query-2d-immutable
0407-trapping-rain-water-ii
0854-making-a-large-island
0945-snakes-and-ladders
1145-number-of-submatrices-that-sum-to-target
1402-count-square-submatrices-with-all-ones
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1628-count-submatrices-with-all-ones
1876-map-of-highest-peak
2145-grid-game
2160-minimum-operations-to-make-a-uni-value-grid
2588-maximum-number-of-points-from-grid-queries
2685-first-completely-painted-row-or-column
2764-maximum-number-of-fish-in-a-grid
3227-find-missing-and-repeated-values
3461-find-the-minimum-area-to-cover-all-ones-i
3628-find-minimum-time-to-reach-last-room-ii
3648-find-the-maximum-number-of-fruits-collected
3733-length-of-longest-v-shaped-diagonal-segment
3748-sort-matrix-by-diagonals

Shortest Path

1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
2090-number-of-ways-to-arrive-at-destination
3628-find-minimum-time-to-reach-last-room-ii

Depth-First Search

0079-word-search
0094-binary-tree-inorder-traversal
0236-lowest-common-ancestor-of-a-binary-tree
0684-redundant-connection
0854-making-a-large-island
1093-recover-a-tree-from-preorder-traversal
1218-lowest-common-ancestor-of-deepest-leaves
1387-find-elements-in-a-contaminated-binary-tree
2400-minimum-score-after-removals-on-a-tree
2564-most-profitable-path-in-a-tree
2764-maximum-number-of-fish-in-a-grid
2793-count-the-number-of-complete-components
3633-maximize-the-number-of-target-nodes-after-connecting-trees-i
3645-maximize-the-number-of-target-nodes-after-connecting-trees-ii

Union Find

0684-redundant-connection
0854-making-a-large-island
1058-lexicographically-smallest-equivalent-string
2583-divide-nodes-into-the-maximum-number-of-groups
2588-maximum-number-of-points-from-grid-queries
2764-maximum-number-of-fish-in-a-grid
2793-count-the-number-of-complete-components
3348-minimum-cost-walk-in-weighted-graph

Design

0146-lru-cache
0155-min-stack
0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0304-range-sum-query-2d-immutable
0460-lfu-cache
0816-design-hashset
0817-design-hashmap
0860-design-circular-queue
0931-maximum-frequency-stack
0937-online-stock-span
1023-time-based-key-value-store
1387-find-elements-in-a-contaminated-binary-tree
1477-product-of-the-last-k-numbers
2434-design-a-number-container-system

Ordered Set

0931-maximum-frequency-stack
2280-count-good-triplets-in-an-array
2434-design-a-number-container-system
3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii

Math

0002-add-two-numbers
0009-palindrome-number
0066-plus-one
0070-climbing-stairs
0150-evaluate-reverse-polish-notation
0231-power-of-two
0326-power-of-three
0679-24-game
0797-rabbits-in-forest
0900-reordered-power-of-2
1411-convert-binary-number-in-a-linked-list-to-integer
1421-find-numbers-with-even-number-of-digits
1448-maximum-69-number
1477-product-of-the-last-k-numbers
1500-count-largest-group
1631-number-of-sub-arrays-with-odd-sum
1889-check-if-number-is-a-sum-of-powers-of-three
1993-sum-of-all-subset-xor-totals
2050-count-good-numbers
2160-minimum-operations-to-make-a-uni-value-grid
2415-count-the-number-of-ideal-arrays
2432-number-of-zero-filled-subarrays
2448-count-number-of-bad-pairs
2610-closest-prime-numbers-in-range
2649-count-total-number-of-colored-cells
2802-find-the-punishment-number-of-an-integer
2998-count-symmetric-integers
3001-apply-operations-to-maximize-score
3172-divisible-and-non-divisible-sums-difference
3227-find-missing-and-repeated-values
3243-count-the-number-of-powerful-integers
3321-type-of-triangle
3548-find-the-count-of-good-integers
3601-find-the-k-th-character-in-string-game-ii
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-ii
3637-count-number-of-balanced-permutations

Simulation

0657-robot-return-to-origin
0682-baseball-game
0735-asteroid-collision
2021-remove-all-occurrences-of-a-substring
2048-build-array-from-permutation
2058-concatenation-of-array
2265-partition-array-according-to-given-pivot
2479-meeting-rooms-iii
2551-apply-operations-to-an-array
3332-minimum-operations-to-exceed-threshold-value-ii
3447-clear-digits
3790-fruits-into-baskets-ii
3811-reverse-degree-of-a-string

Sorting

0015-3sum
0018-4sum
0047-permutations-ii
0049-group-anagrams
0075-sort-colors
0088-merge-sorted-array
0169-majority-element
0217-contains-duplicate
0229-majority-element-ii
0242-valid-anagram
0347-top-k-frequent-elements
0455-assign-cookies
0658-find-k-closest-elements
0883-car-fleet
0900-reordered-power-of-2
0917-boats-to-save-people
0948-sort-an-array
1478-maximum-number-of-events-that-can-be-attended
1851-maximum-number-of-events-that-can-be-attended-ii
2160-minimum-operations-to-make-a-uni-value-grid
2180-maximum-number-of-tasks-you-can-assign
2215-finding-3-digit-even-numbers
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2479-meeting-rooms-iii
2497-maximum-matching-of-players-with-trainers
2588-maximum-number-of-points-from-grid-queries
2681-put-marbles-in-bags
2888-minimum-index-of-a-valid-split
3001-apply-operations-to-maximize-score
3307-find-the-maximum-sum-of-node-values
3321-type-of-triangle
3430-count-days-without-meetings
3647-zero-array-transformation-iii
3748-sort-matrix-by-diagonals
3819-count-covered-buildings

Data Stream

0937-online-stock-span
1477-product-of-the-last-k-numbers

Backtracking

0022-generate-parentheses
0039-combination-sum
0040-combination-sum-ii
0046-permutations
0047-permutations-ii
0051-n-queens
0077-combinations
0078-subsets
0079-word-search
0090-subsets-ii
0131-palindrome-partitioning
0679-24-game
1160-letter-tile-possibilities
1516-the-k-th-lexicographical-string-of-all-happy-strings-of-length-n
1819-construct-the-lexicographically-largest-valid-sequence
1993-sum-of-all-subset-xor-totals
2107-find-unique-binary-string
2170-count-number-of-maximum-bitwise-or-subsets
2456-construct-smallest-number-from-di-string
2802-find-the-punishment-number-of-an-integer

Tree

0094-binary-tree-inorder-traversal
0222-count-complete-tree-nodes
0236-lowest-common-ancestor-of-a-binary-tree
0925-construct-binary-tree-from-preorder-and-postorder-traversal
1093-recover-a-tree-from-preorder-traversal
1218-lowest-common-ancestor-of-deepest-leaves
1387-find-elements-in-a-contaminated-binary-tree
2400-minimum-score-after-removals-on-a-tree
2564-most-profitable-path-in-a-tree
3307-find-the-maximum-sum-of-node-values
3633-maximize-the-number-of-target-nodes-after-connecting-trees-i
3645-maximize-the-number-of-target-nodes-after-connecting-trees-ii

Binary Tree

0094-binary-tree-inorder-traversal
0222-count-complete-tree-nodes
0236-lowest-common-ancestor-of-a-binary-tree
0925-construct-binary-tree-from-preorder-and-postorder-traversal
1093-recover-a-tree-from-preorder-traversal
1218-lowest-common-ancestor-of-deepest-leaves
1387-find-elements-in-a-contaminated-binary-tree

Divide and Conquer

0004-median-of-two-sorted-arrays
0023-merge-k-sorted-lists
0169-majority-element
0191-number-of-1-bits
0347-top-k-frequent-elements
0925-construct-binary-tree-from-preorder-and-postorder-traversal
0948-sort-an-array
2280-count-good-triplets-in-an-array

Dynamic Programming

0022-generate-parentheses
0042-trapping-rain-water
0070-climbing-stairs
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0131-palindrome-partitioning
0410-split-array-largest-sum
0416-partition-equal-subset-sum
0806-domino-and-tromino-tiling
0868-push-dominoes
0905-length-of-longest-fibonacci-subsequence
0934-bitwise-ors-of-subarrays
1170-shortest-common-supersequence
1402-count-square-submatrices-with-all-ones
1586-longest-subarray-of-1s-after-deleting-one-element
1628-count-submatrices-with-all-ones
1631-number-of-sub-arrays-with-odd-sum
1849-maximum-absolute-sum-of-any-subarray
1851-maximum-number-of-events-that-can-be-attended-ii
1986-largest-color-value-in-a-directed-graph
2090-number-of-ways-to-arrive-at-destination
2262-solving-questions-with-brainpower
2415-count-the-number-of-ideal-arrays
2882-ways-to-express-an-integer-as-sum-of-powers
3142-longest-unequal-adjacent-groups-subsequence-ii
3243-count-the-number-of-powerful-integers
3307-find-the-maximum-sum-of-node-values
3490-find-the-maximum-length-of-valid-subsequence-i
3491-find-the-maximum-length-of-valid-subsequence-ii
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-ii
3637-count-number-of-balanced-permutations
3648-find-the-maximum-number-of-fruits-collected
3733-length-of-longest-v-shaped-diagonal-segment

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0023-merge-k-sorted-lists
0092-reverse-linked-list-ii
0138-copy-list-with-random-pointer
0143-reorder-list
0146-lru-cache
0206-reverse-linked-list
0460-lfu-cache
0816-design-hashset
0817-design-hashmap
0860-design-circular-queue
1411-convert-binary-number-in-a-linked-list-to-integer

Merge Sort

0023-merge-k-sorted-lists
0948-sort-an-array
2280-count-good-triplets-in-an-array

Bucket Sort

0347-top-k-frequent-elements
0948-sort-an-array

Radix Sort

0948-sort-an-array

Counting Sort

0948-sort-an-array

Two Pointers

0015-3sum
0018-4sum
0019-remove-nth-node-from-end-of-list
0026-remove-duplicates-from-sorted-array
0042-trapping-rain-water
0075-sort-colors
0088-merge-sorted-array
0125-valid-palindrome
0143-reorder-list
0167-two-sum-ii-input-array-is-sorted
0287-find-the-duplicate-number
0344-reverse-string
0455-assign-cookies
0557-reverse-words-in-a-string-iii
0567-permutation-in-string
0658-find-k-closest-elements
0680-valid-palindrome-ii
0768-partition-labels
0868-push-dominoes
0917-boats-to-save-people
1894-merge-strings-alternately
2265-partition-array-according-to-given-pivot
2497-maximum-matching-of-players-with-trainers
2551-apply-operations-to-an-array
2588-maximum-number-of-points-from-grid-queries
2707-merge-two-2d-arrays-by-summing-values
3683-find-the-lexicographically-largest-string-from-the-box-i

Number Theory

2415-count-the-number-of-ideal-arrays
2610-closest-prime-numbers-in-range
3001-apply-operations-to-maximize-score

Sliding Window

0003-longest-substring-without-repeating-characters
0076-minimum-window-substring
0209-minimum-size-subarray-sum
0219-contains-duplicate-ii
0239-sliding-window-maximum
0424-longest-repeating-character-replacement
0567-permutation-in-string
0658-find-k-closest-elements
0940-fruit-into-baskets
1460-number-of-substrings-containing-all-three-characters
1586-longest-subarray-of-1s-after-deleting-one-element
1813-maximum-erasure-value
2394-count-subarrays-with-score-less-than-k
2463-minimum-recolors-to-get-k-consecutive-black-blocks
2478-longest-nice-subarray
2498-smallest-subarrays-with-maximum-bitwise-or
2527-count-subarrays-with-fixed-bounds
3213-count-subarrays-where-max-element-appears-at-least-k-times
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3483-alternating-groups-ii
3569-count-of-substrings-containing-every-vowel-and-k-consonants-ii
3743-reschedule-meetings-for-maximum-free-time-i

Quickselect

0347-top-k-frequent-elements

Binary Search

0004-median-of-two-sorted-arrays
0035-search-insert-position
0074-search-a-2d-matrix
0081-search-in-rotated-sorted-array-ii
0153-find-minimum-in-rotated-sorted-array
0167-two-sum-ii-input-array-is-sorted
0209-minimum-size-subarray-sum
0222-count-complete-tree-nodes
0287-find-the-duplicate-number
0374-guess-number-higher-or-lower
0410-split-array-largest-sum
0540-single-element-in-a-sorted-array
0658-find-k-closest-elements
0792-binary-search
0882-peak-index-in-a-mountain-array
0907-koko-eating-bananas
1023-time-based-key-value-store
1056-capacity-to-ship-packages-within-d-days
1185-find-in-mountain-array
1335-maximum-candies-allocated-to-k-children
1851-maximum-number-of-events-that-can-be-attended-ii
2180-maximum-number-of-tasks-you-can-assign
2280-count-good-triplets-in-an-array
2394-count-subarrays-with-score-less-than-k
2498-smallest-subarrays-with-maximum-bitwise-or
2614-maximum-count-of-positive-integer-and-negative-integer
2665-minimum-time-to-repair-cars
2690-house-robber-iv
3643-zero-array-transformation-ii
3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii

Segment Tree

2280-count-good-triplets-in-an-array
3789-maximize-subarrays-after-removing-one-conflicting-pair
3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii

Monotonic Stack

0042-trapping-rain-water
0084-largest-rectangle-in-histogram
0739-daily-temperatures
0883-car-fleet
0937-online-stock-span
1628-count-submatrices-with-all-ones
3001-apply-operations-to-maximize-score

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0143-reorder-list
0206-reverse-linked-list
0231-power-of-two
0326-power-of-three
0394-decode-string
2050-count-good-numbers
3601-find-the-k-th-character-in-string-game-ii
3799-unique-3-digit-even-numbers

Enumeration

0900-reordered-power-of-2
1656-count-good-triplets
1993-sum-of-all-subset-xor-totals
2170-count-number-of-maximum-bitwise-or-subsets
2215-finding-3-digit-even-numbers
2998-count-symmetric-integers
3548-find-the-count-of-good-integers
3683-find-the-lexicographically-largest-string-from-the-box-i
3741-reschedule-meetings-for-maximum-free-time-ii
3789-maximize-subarrays-after-removing-one-conflicting-pair
3799-unique-3-digit-even-numbers

Queue

0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0239-sliding-window-maximum
0860-design-circular-queue
2180-maximum-number-of-tasks-you-can-assign
2527-count-subarrays-with-fixed-bounds
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i

Monotonic Queue

0239-sliding-window-maximum
2180-maximum-number-of-tasks-you-can-assign
2527-count-subarrays-with-fixed-bounds

Topological Sort

1986-largest-color-value-in-a-directed-graph
2090-number-of-ways-to-arrive-at-destination
2220-find-all-possible-recipes-from-given-supplies

Interactive

0374-guess-number-higher-or-lower
1185-find-in-mountain-array

Doubly-Linked List

0146-lru-cache
0460-lfu-cache

Combinatorics

1993-sum-of-all-subset-xor-totals
2415-count-the-number-of-ideal-arrays
3548-find-the-count-of-good-integers
3637-count-number-of-balanced-permutations

Binary Indexed Tree

2280-count-good-triplets-in-an-array

Memoization

0070-climbing-stairs
1986-largest-color-value-in-a-directed-graph
3733-length-of-longest-v-shaped-diagonal-segment