A collection of LeetCode questions to ace the coding interview!

LeetCode Topics

Linked List

0002-add-two-numbers
0021-merge-two-sorted-lists
0024-swap-nodes-in-pairs
0061-rotate-list
0109-convert-sorted-list-to-binary-search-tree
0114-flatten-binary-tree-to-linked-list
0117-populating-next-right-pointers-in-each-node-ii
0141-linked-list-cycle
0142-linked-list-cycle-ii
0143-reorder-list
0146-lru-cache
0148-sort-list
0234-palindrome-linked-list
0237-delete-node-in-a-linked-list
0328-odd-even-linked-list
0445-add-two-numbers-ii
0460-lfu-cache
0908-middle-of-the-linked-list
1072-next-greater-node-in-linked-list
1411-convert-binary-number-in-a-linked-list-to-integer
2216-delete-the-middle-node-of-a-linked-list
2236-maximum-twin-sum-of-a-linked-list
2411-spiral-matrix-iv

Stack

0042-trapping-rain-water
0071-simplify-path
0114-flatten-binary-tree-to-linked-list
0143-reorder-list
0150-evaluate-reverse-polish-notation
0155-min-stack
0173-binary-search-tree-iterator
0224-basic-calculator
0234-palindrome-linked-list
0394-decode-string
0445-add-two-numbers-ii
0456-132-pattern
0739-daily-temperatures
0776-n-ary-tree-postorder-traversal
0943-sum-of-subarray-minimums
0957-minimum-add-to-make-parentheses-valid
1072-next-greater-node-in-linked-list
1371-minimum-remove-to-make-valid-parentheses
1818-maximum-score-from-removing-substrings
2227-sum-of-subarray-ranges
2236-maximum-twin-sum-of-a-linked-list
3738-make-array-non-decreasing
3834-minimum-operations-to-convert-all-elements-to-zero

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
0108-convert-sorted-array-to-binary-search-tree
0109-convert-sorted-list-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
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
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0236-lowest-common-ancestor-of-a-binary-tree
0297-serialize-and-deserialize-binary-tree
0437-path-sum-iii
0449-serialize-and-deserialize-bst
0513-find-bottom-left-tree-value
0530-minimum-absolute-difference-in-bst
0637-average-of-levels-in-binary-tree
0655-print-binary-tree
0662-maximum-width-of-binary-tree
0772-construct-quad-tree
0776-n-ary-tree-postorder-traversal
0783-search-in-a-binary-search-tree
0799-minimum-distance-between-bst-nodes
2400-minimum-score-after-removals-on-a-tree
2646-kth-largest-sum-in-a-binary-tree

Depth-First Search

0079-word-search
0098-validate-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
0117-populating-next-right-pointers-in-each-node-ii
0124-binary-tree-maximum-path-sum
0129-sum-root-to-leaf-numbers
0130-surrounded-regions
0133-clone-graph
0199-binary-tree-right-side-view
0200-number-of-islands
0207-course-schedule
0210-course-schedule-ii
0211-design-add-and-search-words-data-structure
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0236-lowest-common-ancestor-of-a-binary-tree
0297-serialize-and-deserialize-binary-tree
0365-water-and-jug-problem
0386-lexicographical-numbers
0399-evaluate-division
0417-pacific-atlantic-water-flow
0437-path-sum-iii
0449-serialize-and-deserialize-bst
0472-concatenated-words
0513-find-bottom-left-tree-value
0530-minimum-absolute-difference-in-bst
0637-average-of-levels-in-binary-tree
0655-print-binary-tree
0662-maximum-width-of-binary-tree
0733-flood-fill
0776-n-ary-tree-postorder-traversal
0799-minimum-distance-between-bst-nodes
0801-is-graph-bipartite
0813-all-paths-from-source-to-target
0820-find-eventual-safe-states
1350-remove-sub-folders-from-the-filesystem
1747-lexicographically-smallest-string-after-applying-operations
2400-minimum-score-after-removals-on-a-tree
2439-longest-cycle-in-a-graph
2641-disconnect-path-in-a-binary-matrix-by-at-most-one-flip
2662-check-knight-tour-configuration

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
0108-convert-sorted-array-to-binary-search-tree
0109-convert-sorted-list-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
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
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0236-lowest-common-ancestor-of-a-binary-tree
0297-serialize-and-deserialize-binary-tree
0437-path-sum-iii
0449-serialize-and-deserialize-bst
0513-find-bottom-left-tree-value
0530-minimum-absolute-difference-in-bst
0637-average-of-levels-in-binary-tree
0655-print-binary-tree
0662-maximum-width-of-binary-tree
0783-search-in-a-binary-search-tree
0799-minimum-distance-between-bst-nodes
2646-kth-largest-sum-in-a-binary-tree

Binary Search Tree

0004-median-of-two-sorted-arrays
0033-search-in-rotated-sorted-array
0069-sqrtx
0081-search-in-rotated-sorted-array-ii
0098-validate-binary-search-tree
0108-convert-sorted-array-to-binary-search-tree
0109-convert-sorted-list-to-binary-search-tree
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0173-binary-search-tree-iterator
0230-kth-smallest-element-in-a-bst
0268-missing-number
0275-h-index-ii
0300-longest-increasing-subsequence
0315-count-of-smaller-numbers-after-self
0374-guess-number-higher-or-lower
0378-kth-smallest-element-in-a-sorted-matrix
0449-serialize-and-deserialize-bst
0456-132-pattern
0530-minimum-absolute-difference-in-bst
0611-valid-triangle-number
0783-search-in-a-binary-search-tree
0799-minimum-distance-between-bst-nodes
0892-shortest-subarray-with-sum-at-least-k
0907-koko-eating-bananas
0923-super-egg-drop
1408-find-the-smallest-divisor-given-a-threshold
1605-minimum-number-of-days-to-make-m-bouquets
1612-avoid-flood-in-the-city
1851-maximum-number-of-events-that-can-be-attended-ii
2134-maximize-the-confusion-of-an-exam
2150-kth-smallest-product-of-two-sorted-arrays
2229-maximum-fruits-harvested-after-at-most-k-steps
2392-successful-pairs-of-spells-and-potions
2394-count-subarrays-with-score-less-than-k
2449-maximum-number-of-robots-within-budget
2469-longest-subsequence-with-limited-sum
2498-smallest-subarrays-with-maximum-bitwise-or
2699-count-the-number-of-fair-pairs
3437-maximum-total-damage-with-spell-casting
3466-number-of-subarrays-with-and-value-of-k
3619-adjacent-increasing-subarrays-detection-ii
3622-maximum-frequency-of-an-element-after-performing-operations-i
3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii

Array

0001-two-sum
0004-median-of-two-sorted-arrays
0011-container-with-most-water
0015-3sum
0026-remove-duplicates-from-sorted-array
0031-next-permutation
0033-search-in-rotated-sorted-array
0036-valid-sudoku
0037-sudoku-solver
0039-combination-sum
0041-first-missing-positive
0042-trapping-rain-water
0046-permutations
0047-permutations-ii
0049-group-anagrams
0056-merge-intervals
0063-unique-paths-ii
0064-minimum-path-sum
0066-plus-one
0073-set-matrix-zeroes
0075-sort-colors
0079-word-search
0081-search-in-rotated-sorted-array-ii
0090-subsets-ii
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0108-convert-sorted-array-to-binary-search-tree
0118-pascals-triangle
0120-triangle
0121-best-time-to-buy-and-sell-stock
0123-best-time-to-buy-and-sell-stock-iii
0130-surrounded-regions
0134-gas-station
0136-single-number
0137-single-number-ii
0139-word-break
0140-word-break-ii
0149-max-points-on-a-line
0150-evaluate-reverse-polish-notation
0152-maximum-product-subarray
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0188-best-time-to-buy-and-sell-stock-iv
0198-house-robber
0200-number-of-islands
0212-word-search-ii
0213-house-robber-ii
0215-kth-largest-element-in-an-array
0216-combination-sum-iii
0217-contains-duplicate
0219-contains-duplicate-ii
0221-maximal-square
0238-product-of-array-except-self
0239-sliding-window-maximum
0260-single-number-iii
0268-missing-number
0275-h-index-ii
0300-longest-increasing-subsequence
0303-range-sum-query-immutable
0307-range-sum-query-mutable
0315-count-of-smaller-numbers-after-self
0318-maximum-product-of-word-lengths
0322-coin-change
0373-find-k-pairs-with-smallest-sums
0378-kth-smallest-element-in-a-sorted-matrix
0399-evaluate-division
0417-pacific-atlantic-water-flow
0421-maximum-xor-of-two-numbers-in-an-array
0456-132-pattern
0472-concatenated-words
0474-ones-and-zeroes
0485-max-consecutive-ones
0498-diagonal-traverse
0502-ipo
0518-coin-change-ii
0525-contiguous-array
0560-subarray-sum-equals-k
0594-longest-harmonious-subsequence
0611-valid-triangle-number
0674-longest-continuous-increasing-subsequence
0692-top-k-frequent-words
0720-longest-word-in-dictionary
0724-find-pivot-index
0733-flood-fill
0739-daily-temperatures
0772-construct-quad-tree
0797-rabbits-in-forest
0830-largest-triangle-area
0840-magic-squares-in-grid
0875-longest-mountain-in-array
0892-shortest-subarray-with-sum-at-least-k
0895-shortest-path-to-get-all-keys
0902-minimum-number-of-refueling-stops
0907-koko-eating-bananas
0934-bitwise-ors-of-subarrays
0940-fruit-into-baskets
0943-sum-of-subarray-minimums
0944-smallest-range-i
0944-delete-columns-to-make-sorted
0945-snakes-and-ladders
0954-maximum-sum-circular-subarray
0961-n-repeated-element-in-size-2n-array
0966-binary-subarrays-with-sum
0978-valid-mountain-array
1016-subarray-sums-divisible-by-k
1018-largest-perimeter-triangle
1018-binary-prefix-divisible-by-5
1019-squares-of-a-sorted-array
1022-unique-paths-iii
1034-subarrays-with-k-different-integers
1037-minimum-number-of-k-consecutive-bit-flips
1039-find-the-town-judge
1072-next-greater-node-in-linked-list
1127-last-stone-weight
1227-number-of-equivalent-domino-pairs
1293-three-consecutive-odds
1350-remove-sub-folders-from-the-filesystem
1353-find-resultant-array-after-removing-anagrams
1370-count-number-of-nice-subarrays
1390-four-divisors
1402-count-square-submatrices-with-all-ones
1408-find-the-smallest-divisor-given-a-threshold
1414-shortest-path-in-a-grid-with-obstacles-elimination
1421-find-numbers-with-even-number-of-digits
1426-find-n-unique-integers-sum-up-to-zero
1435-xor-queries-of-a-subarray
1470-shuffle-the-array
1478-maximum-number-of-events-that-can-be-attended
1489-pizza-with-3n-slices
1503-reducing-dishes
1510-find-lucky-integer-in-an-array
1586-longest-subarray-of-1s-after-deleting-one-element
1605-minimum-number-of-days-to-make-m-bouquets
1612-avoid-flood-in-the-city
1656-count-good-triplets
1669-minimum-cost-to-cut-a-stick
1690-maximum-length-of-subarray-with-positive-product
1699-number-of-ways-where-square-of-number-is-equal-to-product-of-two-numbers
1741-sort-array-by-increasing-frequency
1798-max-number-of-k-sum-pairs
1813-maximum-erasure-value
1826-maximum-xor-with-an-element-from-array
1829-maximum-units-on-a-truck
1833-find-the-highest-altitude
1851-maximum-number-of-events-that-can-be-attended-ii
1878-check-if-array-is-sorted-and-rotated
1929-concatenation-of-array
1938-minimum-operations-to-make-the-array-increasing
1975-maximum-matrix-sum
1995-finding-pairs-with-a-certain-sum
2038-nearest-exit-from-entrance-in-maze
2048-build-array-from-permutation
2079-delete-duplicate-folders-in-system
2129-number-of-pairs-of-interchangeable-rectangles
2132-convert-1d-array-into-2d-array
2137-final-value-of-variable-after-performing-operations
2144-maximum-difference-between-increasing-elements
2150-kth-smallest-product-of-two-sorted-arrays
2169-simple-bank-system
2170-count-number-of-maximum-bitwise-or-subsets
2199-two-furthest-houses-with-different-colors
2204-find-subsequence-of-length-k-with-the-largest-sum
2205-find-good-days-to-rob-the-bank
2215-finding-3-digit-even-numbers
2227-sum-of-subarray-ranges
2229-maximum-fruits-harvested-after-at-most-k-steps
2237-longest-palindrome-by-concatenating-two-letter-words
2244-number-of-laser-beams-in-a-bank
2254-check-if-every-row-and-column-contains-all-numbers
2267-minimum-difference-in-sums-after-removal-of-elements
2271-rearrange-array-elements-by-sign
2277-count-equal-and-divisible-pairs-in-an-array
2316-count-hills-and-valleys-in-an-array
2320-find-all-k-distant-indices-in-an-array
2324-find-triangular-sum-of-an-array
2343-count-unguarded-cells-in-the-grid
2362-minimum-rounds-to-complete-all-tasks
2387-partition-array-such-that-maximum-difference-is-k
2392-successful-pairs-of-spells-and-potions
2394-count-subarrays-with-score-less-than-k
2400-minimum-score-after-removals-on-a-tree
2411-spiral-matrix-iv
2432-number-of-zero-filled-subarrays
2435-paths-in-matrix-whose-sum-is-divisible-by-k
2449-maximum-number-of-robots-within-budget
2454-largest-local-values-in-a-matrix
2469-longest-subsequence-with-limited-sum
2479-meeting-rooms-iii
2480-find-subarrays-with-equal-sum
2497-maximum-matching-of-players-with-trainers
2498-smallest-subarrays-with-maximum-bitwise-or
2503-longest-subarray-with-maximum-bitwise-and
2529-range-product-queries-of-powers
2594-count-pairs-of-similar-strings
2641-disconnect-path-in-a-binary-matrix-by-at-most-one-flip
2661-smallest-missing-non-negative-integer-after-operations
2662-check-knight-tour-configuration
2689-rearranging-fruits
2699-count-the-number-of-fair-pairs
2855-maximum-number-of-jumps-to-reach-the-last-index
2856-count-complete-subarrays-in-an-array
3093-sum-of-values-at-indices-with-k-set-bits
3106-length-of-the-longest-subsequence-that-sums-to-target
3143-longest-unequal-adjacent-groups-subsequence-i
3171-minimum-equal-sum-of-two-arrays-after-replacing-zeros
3190-find-minimum-operations-to-make-all-elements-divisible-by-three
3194-find-words-containing-character
3213-count-subarrays-where-max-element-appears-at-least-k-times
3241-divide-array-into-arrays-with-max-difference
3242-count-elements-with-maximum-frequency
3251-maximum-area-of-longest-diagonal-rectangle
3278-find-the-number-of-ways-to-place-people-i
3381-maximum-subarray-sum-with-length-divisible-by-k
3383-taking-maximum-energy-from-the-mystic-dungeon
3437-maximum-total-damage-with-spell-casting
3466-number-of-subarrays-with-and-value-of-k
3490-find-the-maximum-length-of-valid-subsequence-i
3491-find-the-maximum-length-of-valid-subsequence-ii
3516-design-neighbor-sum-service
3531-count-covered-buildings
3573-best-time-to-buy-and-sell-stock-v
3577-count-the-number-of-computer-unlocking-permutations
3583-count-special-triplets
3610-find-x-sum-of-all-k-long-subarrays-i
3612-adjacent-increasing-subarrays-detection-i
3616-make-array-elements-equal-to-zero
3619-adjacent-increasing-subarrays-detection-ii
3620-maximum-number-of-distinct-elements-after-operations
3622-maximum-frequency-of-an-element-after-performing-operations-i
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii
3639-zero-array-transformation-i
3648-find-the-maximum-number-of-fruits-collected
3685-count-subarrays-of-length-three-with-a-condition
3738-make-array-non-decreasing
3741-reschedule-meetings-for-maximum-free-time-ii
3743-reschedule-meetings-for-maximum-free-time-i
3747-maximum-difference-between-adjacent-elements-in-a-circular-array
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
3797-design-spreadsheet
3819-count-covered-buildings
3834-minimum-operations-to-convert-all-elements-to-zero

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0012-integer-to-roman
0017-letter-combinations-of-a-phone-number
0030-substring-with-concatenation-of-all-words
0036-valid-sudoku
0037-sudoku-solver
0041-first-missing-positive
0049-group-anagrams
0073-set-matrix-zeroes
0076-minimum-window-substring
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0127-word-ladder
0133-clone-graph
0139-word-break
0140-word-break-ii
0141-linked-list-cycle
0142-linked-list-cycle-ii
0146-lru-cache
0149-max-points-on-a-line
0208-implement-trie-prefix-tree
0217-contains-duplicate
0219-contains-duplicate-ii
0268-missing-number
0387-first-unique-character-in-a-string
0409-longest-palindrome
0421-maximum-xor-of-two-numbers-in-an-array
0424-longest-repeating-character-replacement
0433-minimum-genetic-mutation
0460-lfu-cache
0525-contiguous-array
0560-subarray-sum-equals-k
0594-longest-harmonious-subsequence
0692-top-k-frequent-words
0720-longest-word-in-dictionary
0756-pyramid-transition-matrix
0778-reorganize-string
0797-rabbits-in-forest
0840-magic-squares-in-grid
0900-reordered-power-of-2
0940-fruit-into-baskets
0961-n-repeated-element-in-size-2n-array
0966-binary-subarrays-with-sum
1015-smallest-integer-divisible-by-k
1016-subarray-sums-divisible-by-k
1034-subarrays-with-k-different-integers
1039-find-the-town-judge
1227-number-of-equivalent-domino-pairs
1264-maximum-number-of-words-you-can-type
1353-find-resultant-array-after-removing-anagrams
1370-count-number-of-nice-subarrays
1500-count-largest-group
1510-find-lucky-integer-in-an-array
1612-avoid-flood-in-the-city
1699-number-of-ways-where-square-of-number-is-equal-to-product-of-two-numbers
1741-sort-array-by-increasing-frequency
1798-max-number-of-k-sum-pairs
1813-maximum-erasure-value
1930-unique-length-3-palindromic-subsequences
1933-number-of-different-integers-in-a-string
1995-finding-pairs-with-a-certain-sum
2079-delete-duplicate-folders-in-system
2129-number-of-pairs-of-interchangeable-rectangles
2169-simple-bank-system
2174-next-greater-numerically-balanced-number
2204-find-subsequence-of-length-k-with-the-largest-sum
2215-finding-3-digit-even-numbers
2237-longest-palindrome-by-concatenating-two-letter-words
2254-check-if-every-row-and-column-contains-all-numbers
2362-minimum-rounds-to-complete-all-tasks
2479-meeting-rooms-iii
2480-find-subarrays-with-equal-sum
2594-count-pairs-of-similar-strings
2661-smallest-missing-non-negative-integer-after-operations
2689-rearranging-fruits
2856-count-complete-subarrays-in-an-array
3242-count-elements-with-maximum-frequency
3360-minimum-deletions-to-make-string-k-special
3381-maximum-subarray-sum-with-length-divisible-by-k
3437-maximum-total-damage-with-spell-casting
3516-design-neighbor-sum-service
3531-count-covered-buildings
3583-count-special-triplets
3610-find-x-sum-of-all-k-long-subarrays-i
3629-total-characters-in-string-after-transformations-i
3753-maximum-difference-between-even-and-odd-frequency-i
3754-maximum-manhattan-distance-after-k-changes
3788-maximum-unique-subarray-sum-after-deletion
3797-design-spreadsheet
3819-count-covered-buildings
3834-minimum-operations-to-convert-all-elements-to-zero
3872-find-most-frequent-vowel-and-consonant

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0006-zigzag-conversion
0008-string-to-integer-atoi
0012-integer-to-roman
0017-letter-combinations-of-a-phone-number
0022-generate-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string
0030-substring-with-concatenation-of-all-words
0038-count-and-say
0043-multiply-strings
0049-group-anagrams
0067-add-binary
0071-simplify-path
0072-edit-distance
0076-minimum-window-substring
0079-word-search
0093-restore-ip-addresses
0127-word-ladder
0131-palindrome-partitioning
0139-word-break
0140-word-break-ii
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0212-word-search-ii
0214-shortest-palindrome
0224-basic-calculator
0297-serialize-and-deserialize-binary-tree
0318-maximum-product-of-word-lengths
0344-reverse-string
0387-first-unique-character-in-a-string
0394-decode-string
0399-evaluate-division
0409-longest-palindrome
0424-longest-repeating-character-replacement
0433-minimum-genetic-mutation
0449-serialize-and-deserialize-bst
0459-repeated-substring-pattern
0472-concatenated-words
0474-ones-and-zeroes
0516-longest-palindromic-subsequence
0551-student-attendance-record-i
0647-palindromic-substrings
0692-top-k-frequent-words
0720-longest-word-in-dictionary
0756-pyramid-transition-matrix
0778-reorganize-string
0812-rotate-string
0944-delete-columns-to-make-sorted
0957-minimum-add-to-make-parentheses-valid
1058-lexicographically-smallest-equivalent-string
1250-longest-common-subsequence
1264-maximum-number-of-words-you-can-type
1302-delete-characters-to-make-fancy-string
1350-remove-sub-folders-from-the-filesystem
1353-find-resultant-array-after-removing-anagrams
1371-minimum-remove-to-make-valid-parentheses
1430-find-the-k-beauty-of-a-number
1508-longest-happy-prefix
1567-maximum-number-of-vowels-in-a-substring-of-given-length
1636-number-of-substrings-with-only-1s
1747-lexicographically-smallest-string-after-applying-operations
1818-maximum-score-from-removing-substrings
1930-unique-length-3-palindromic-subsequences
1933-number-of-different-integers-in-a-string
2079-delete-duplicate-folders-in-system
2134-maximize-the-confusion-of-an-exam
2137-final-value-of-variable-after-performing-operations
2168-check-if-numbers-are-ascending-in-a-sentence
2237-longest-palindrome-by-concatenating-two-letter-words
2244-number-of-laser-beams-in-a-bank
2260-divide-a-string-into-groups-of-size-k
2325-number-of-ways-to-select-buildings
2346-largest-3-same-digit-number-in-string
2594-count-pairs-of-similar-strings
2887-sort-vowels-in-a-string
3143-longest-unequal-adjacent-groups-subsequence-i
3194-find-words-containing-character
3360-minimum-deletions-to-make-string-k-special
3396-valid-word
3566-find-the-sequence-of-strings-appeared-on-the-screen
3617-find-the-original-typed-string-i
3618-find-the-original-typed-string-ii
3629-total-characters-in-string-after-transformations-i
3753-maximum-difference-between-even-and-odd-frequency-i
3754-maximum-manhattan-distance-after-k-changes
3768-check-if-digits-are-equal-in-string-after-operations-i
3797-design-spreadsheet
3872-find-most-frequent-vowel-and-consonant
3893-generate-tag-for-video-caption

Enumeration

0875-longest-mountain-in-array
0900-reordered-power-of-2
1656-count-good-triplets
1747-lexicographically-smallest-string-after-applying-operations
1925-count-square-sum-triples
2170-count-number-of-maximum-bitwise-or-subsets
2174-next-greater-numerically-balanced-number
2202-sum-of-k-mirror-numbers
2215-finding-3-digit-even-numbers
3278-find-the-number-of-ways-to-place-people-i
3741-reschedule-meetings-for-maximum-free-time-ii
3789-maximize-subarrays-after-removing-one-conflicting-pair

Monotonic Stack

0042-trapping-rain-water
0456-132-pattern
0739-daily-temperatures
0943-sum-of-subarray-minimums
1072-next-greater-node-in-linked-list
2227-sum-of-subarray-ranges
3738-make-array-non-decreasing
3834-minimum-operations-to-convert-all-elements-to-zero

Backtracking

0017-letter-combinations-of-a-phone-number
0022-generate-parentheses
0037-sudoku-solver
0039-combination-sum
0046-permutations
0047-permutations-ii
0052-n-queens-ii
0077-combinations
0079-word-search
0090-subsets-ii
0093-restore-ip-addresses
0113-path-sum-ii
0131-palindrome-partitioning
0140-word-break-ii
0212-word-search-ii
0216-combination-sum-iii
0756-pyramid-transition-matrix
0813-all-paths-from-source-to-target
1022-unique-paths-iii
2170-count-number-of-maximum-bitwise-or-subsets
2174-next-greater-numerically-balanced-number

Two Pointers

0005-longest-palindromic-substring
0011-container-with-most-water
0015-3sum
0026-remove-duplicates-from-sorted-array
0028-find-the-index-of-the-first-occurrence-in-a-string
0031-next-permutation
0042-trapping-rain-water
0061-rotate-list
0075-sort-colors
0141-linked-list-cycle
0142-linked-list-cycle-ii
0143-reorder-list
0148-sort-list
0234-palindrome-linked-list
0295-find-median-from-data-stream
0344-reverse-string
0611-valid-triangle-number
0647-palindromic-substrings
0875-longest-mountain-in-array
0908-middle-of-the-linked-list
1019-squares-of-a-sorted-array
1699-number-of-ways-where-square-of-number-is-equal-to-product-of-two-numbers
1798-max-number-of-k-sum-pairs
2216-delete-the-middle-node-of-a-linked-list
2236-maximum-twin-sum-of-a-linked-list
2271-rearrange-array-elements-by-sign
2320-find-all-k-distant-indices-in-an-array
2392-successful-pairs-of-spells-and-potions
2481-strictly-palindromic-number
2497-maximum-matching-of-players-with-trainers
2699-count-the-number-of-fair-pairs
3437-maximum-total-damage-with-spell-casting

Sorting

0015-3sum
0047-permutations-ii
0049-group-anagrams
0056-merge-intervals
0075-sort-colors
0148-sort-list
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0268-missing-number
0295-find-median-from-data-stream
0378-kth-smallest-element-in-a-sorted-matrix
0502-ipo
0594-longest-harmonious-subsequence
0611-valid-triangle-number
0692-top-k-frequent-words
0720-longest-word-in-dictionary
0778-reorganize-string
0900-reordered-power-of-2
1018-largest-perimeter-triangle
1019-squares-of-a-sorted-array
1353-find-resultant-array-after-removing-anagrams
1478-maximum-number-of-events-that-can-be-attended
1503-reducing-dishes
1669-minimum-cost-to-cut-a-stick
1741-sort-array-by-increasing-frequency
1798-max-number-of-k-sum-pairs
1829-maximum-units-on-a-truck
1851-maximum-number-of-events-that-can-be-attended-ii
2204-find-subsequence-of-length-k-with-the-largest-sum
2215-finding-3-digit-even-numbers
2387-partition-array-such-that-maximum-difference-is-k
2392-successful-pairs-of-spells-and-potions
2469-longest-subsequence-with-limited-sum
2479-meeting-rooms-iii
2497-maximum-matching-of-players-with-trainers
2646-kth-largest-sum-in-a-binary-tree
2689-rearranging-fruits
2699-count-the-number-of-fair-pairs
2887-sort-vowels-in-a-string
3241-divide-array-into-arrays-with-max-difference
3278-find-the-number-of-ways-to-place-people-i
3360-minimum-deletions-to-make-string-k-special
3437-maximum-total-damage-with-spell-casting
3531-count-covered-buildings
3620-maximum-number-of-distinct-elements-after-operations
3622-maximum-frequency-of-an-element-after-performing-operations-i
3748-sort-matrix-by-diagonals
3819-count-covered-buildings

Interactive

0374-guess-number-higher-or-lower

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
0111-minimum-depth-of-binary-tree
0112-path-sum
0117-populating-next-right-pointers-in-each-node-ii
0127-word-ladder
0130-surrounded-regions
0133-clone-graph
0199-binary-tree-right-side-view
0200-number-of-islands
0207-course-schedule
0210-course-schedule-ii
0226-invert-binary-tree
0279-perfect-squares
0297-serialize-and-deserialize-binary-tree
0322-coin-change
0365-water-and-jug-problem
0399-evaluate-division
0417-pacific-atlantic-water-flow
0433-minimum-genetic-mutation
0449-serialize-and-deserialize-bst
0513-find-bottom-left-tree-value
0530-minimum-absolute-difference-in-bst
0637-average-of-levels-in-binary-tree
0655-print-binary-tree
0662-maximum-width-of-binary-tree
0733-flood-fill
0799-minimum-distance-between-bst-nodes
0801-is-graph-bipartite
0813-all-paths-from-source-to-target
0820-find-eventual-safe-states
0895-shortest-path-to-get-all-keys
0945-snakes-and-ladders
1414-shortest-path-in-a-grid-with-obstacles-elimination
1747-lexicographically-smallest-string-after-applying-operations
2038-nearest-exit-from-entrance-in-maze
2439-longest-cycle-in-a-graph
2641-disconnect-path-in-a-binary-matrix-by-at-most-one-flip
2646-kth-largest-sum-in-a-binary-tree
2662-check-knight-tour-configuration
3239-minimum-number-of-operations-to-make-x-and-y-equal

Matrix

0036-valid-sudoku
0037-sudoku-solver
0063-unique-paths-ii
0064-minimum-path-sum
0073-set-matrix-zeroes
0079-word-search
0130-surrounded-regions
0200-number-of-islands
0212-word-search-ii
0221-maximal-square
0378-kth-smallest-element-in-a-sorted-matrix
0417-pacific-atlantic-water-flow
0498-diagonal-traverse
0733-flood-fill
0772-construct-quad-tree
0840-magic-squares-in-grid
0895-shortest-path-to-get-all-keys
0945-snakes-and-ladders
1022-unique-paths-iii
1402-count-square-submatrices-with-all-ones
1414-shortest-path-in-a-grid-with-obstacles-elimination
1975-maximum-matrix-sum
2038-nearest-exit-from-entrance-in-maze
2132-convert-1d-array-into-2d-array
2244-number-of-laser-beams-in-a-bank
2254-check-if-every-row-and-column-contains-all-numbers
2343-count-unguarded-cells-in-the-grid
2411-spiral-matrix-iv
2435-paths-in-matrix-whose-sum-is-divisible-by-k
2454-largest-local-values-in-a-matrix
2641-disconnect-path-in-a-binary-matrix-by-at-most-one-flip
2662-check-knight-tour-configuration
3516-design-neighbor-sum-service
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii
3648-find-the-maximum-number-of-fruits-collected
3748-sort-matrix-by-diagonals
3797-design-spreadsheet

Math

0002-add-two-numbers
0007-reverse-integer
0009-palindrome-number
0012-integer-to-roman
0029-divide-two-integers
0043-multiply-strings
0050-powx-n
0060-permutation-sequence
0066-plus-one
0067-add-binary
0069-sqrtx
0070-climbing-stairs
0149-max-points-on-a-line
0150-evaluate-reverse-polish-notation
0172-factorial-trailing-zeroes
0224-basic-calculator
0231-power-of-two
0263-ugly-number
0268-missing-number
0279-perfect-squares
0326-power-of-three
0342-power-of-four
0365-water-and-jug-problem
0445-add-two-numbers-ii
0797-rabbits-in-forest
0826-soup-servings
0830-largest-triangle-area
0840-magic-squares-in-grid
0867-new-21-game
0900-reordered-power-of-2
0923-super-egg-drop
0944-smallest-range-i
1013-fibonacci-number
1015-smallest-integer-divisible-by-k
1018-largest-perimeter-triangle
1370-count-number-of-nice-subarrays
1390-four-divisors
1411-convert-binary-number-in-a-linked-list-to-integer
1421-find-numbers-with-even-number-of-digits
1426-find-n-unique-integers-sum-up-to-zero
1430-find-the-k-beauty-of-a-number
1440-convert-integer-to-the-sum-of-two-no-zero-integers
1448-maximum-69-number
1500-count-largest-group
1523-count-odd-numbers-in-an-interval-range
1529-max-difference-you-can-get-from-changing-an-integer
1636-number-of-substrings-with-only-1s
1642-water-bottles
1699-number-of-ways-where-square-of-number-is-equal-to-product-of-two-numbers
1817-calculate-money-in-leetcode-bank
1925-count-square-sum-triples
2031-egg-drop-with-2-eggs-and-n-floors
2129-number-of-pairs-of-interchangeable-rectangles
2174-next-greater-numerically-balanced-number
2202-sum-of-k-mirror-numbers
2244-number-of-laser-beams-in-a-bank
2324-find-triangular-sum-of-an-array
2432-number-of-zero-filled-subarrays
2481-strictly-palindromic-number
2661-smallest-missing-non-negative-integer-after-operations
2752-sum-multiples
3190-find-minimum-operations-to-make-all-elements-divisible-by-three
3278-find-the-number-of-ways-to-place-people-i
3577-count-the-number-of-computer-unlocking-permutations
3600-find-the-k-th-character-in-string-game-i
3601-find-the-k-th-character-in-string-game-ii
3629-total-characters-in-string-after-transformations-i
3676-smallest-number-with-all-set-bits
3754-maximum-manhattan-distance-after-k-changes
3768-check-if-digits-are-equal-in-string-after-operations-i

Prefix Sum

0238-product-of-array-except-self
0303-range-sum-query-immutable
0525-contiguous-array
0560-subarray-sum-equals-k
0724-find-pivot-index
0892-shortest-subarray-with-sum-at-least-k
0966-binary-subarrays-with-sum
1016-subarray-sums-divisible-by-k
1037-minimum-number-of-k-consecutive-bit-flips
1370-count-number-of-nice-subarrays
1435-xor-queries-of-a-subarray
1833-find-the-highest-altitude
1930-unique-length-3-palindromic-subsequences
2134-maximize-the-confusion-of-an-exam
2205-find-good-days-to-rob-the-bank
2229-maximum-fruits-harvested-after-at-most-k-steps
2325-number-of-ways-to-select-buildings
2394-count-subarrays-with-score-less-than-k
2449-maximum-number-of-robots-within-budget
2469-longest-subsequence-with-limited-sum
2529-range-product-queries-of-powers
3381-maximum-subarray-sum-with-length-divisible-by-k
3383-taking-maximum-energy-from-the-mystic-dungeon
3616-make-array-elements-equal-to-zero
3618-find-the-original-typed-string-ii
3622-maximum-frequency-of-an-element-after-performing-operations-i
3639-zero-array-transformation-i
3789-maximize-subarrays-after-removing-one-conflicting-pair

Sliding Window

0003-longest-substring-without-repeating-characters
0030-substring-with-concatenation-of-all-words
0076-minimum-window-substring
0219-contains-duplicate-ii
0239-sliding-window-maximum
0424-longest-repeating-character-replacement
0594-longest-harmonious-subsequence
0867-new-21-game
0892-shortest-subarray-with-sum-at-least-k
0940-fruit-into-baskets
0966-binary-subarrays-with-sum
1034-subarrays-with-k-different-integers
1037-minimum-number-of-k-consecutive-bit-flips
1370-count-number-of-nice-subarrays
1430-find-the-k-beauty-of-a-number
1567-maximum-number-of-vowels-in-a-substring-of-given-length
1586-longest-subarray-of-1s-after-deleting-one-element
1813-maximum-erasure-value
2134-maximize-the-confusion-of-an-exam
2229-maximum-fruits-harvested-after-at-most-k-steps
2394-count-subarrays-with-score-less-than-k
2449-maximum-number-of-robots-within-budget
2498-smallest-subarrays-with-maximum-bitwise-or
2856-count-complete-subarrays-in-an-array
3213-count-subarrays-where-max-element-appears-at-least-k-times
3610-find-x-sum-of-all-k-long-subarrays-i
3622-maximum-frequency-of-an-element-after-performing-operations-i
3743-reschedule-meetings-for-maximum-free-time-i

Dynamic Programming

0005-longest-palindromic-substring
0022-generate-parentheses
0042-trapping-rain-water
0063-unique-paths-ii
0064-minimum-path-sum
0070-climbing-stairs
0072-edit-distance
0118-pascals-triangle
0120-triangle
0121-best-time-to-buy-and-sell-stock
0123-best-time-to-buy-and-sell-stock-iii
0124-binary-tree-maximum-path-sum
0131-palindrome-partitioning
0139-word-break
0140-word-break-ii
0152-maximum-product-subarray
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
0472-concatenated-words
0474-ones-and-zeroes
0516-longest-palindromic-subsequence
0518-coin-change-ii
0647-palindromic-substrings
0826-soup-servings
0867-new-21-game
0875-longest-mountain-in-array
0902-minimum-number-of-refueling-stops
0923-super-egg-drop
0934-bitwise-ors-of-subarrays
0943-sum-of-subarray-minimums
0954-maximum-sum-circular-subarray
1013-fibonacci-number
1250-longest-common-subsequence
1402-count-square-submatrices-with-all-ones
1489-pizza-with-3n-slices
1503-reducing-dishes
1586-longest-subarray-of-1s-after-deleting-one-element
1669-minimum-cost-to-cut-a-stick
1690-maximum-length-of-subarray-with-positive-product
1851-maximum-number-of-events-that-can-be-attended-ii
2028-the-earliest-and-latest-rounds-where-players-compete
2031-egg-drop-with-2-eggs-and-n-floors
2061-painting-a-grid-with-three-different-colors
2205-find-good-days-to-rob-the-bank
2267-minimum-difference-in-sums-after-removal-of-elements
2325-number-of-ways-to-select-buildings
2435-paths-in-matrix-whose-sum-is-divisible-by-k
2641-disconnect-path-in-a-binary-matrix-by-at-most-one-flip
2855-maximum-number-of-jumps-to-reach-the-last-index
2882-ways-to-express-an-integer-as-sum-of-powers
3106-length-of-the-longest-subsequence-that-sums-to-target
3143-longest-unequal-adjacent-groups-subsequence-i
3239-minimum-number-of-operations-to-make-x-and-y-equal
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
3573-best-time-to-buy-and-sell-stock-v
3618-find-the-original-typed-string-ii
3629-total-characters-in-string-after-transformations-i
3648-find-the-maximum-number-of-fruits-collected

Design

0146-lru-cache
0155-min-stack
0173-binary-search-tree-iterator
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0295-find-median-from-data-stream
0297-serialize-and-deserialize-binary-tree
0303-range-sum-query-immutable
0307-range-sum-query-mutable
0449-serialize-and-deserialize-bst
0460-lfu-cache
1708-design-parking-system
1995-finding-pairs-with-a-certain-sum
2169-simple-bank-system
3516-design-neighbor-sum-service
3797-design-spreadsheet

Binary Indexed Tree

0307-range-sum-query-mutable
0315-count-of-smaller-numbers-after-self

Segment Tree

0307-range-sum-query-mutable
0315-count-of-smaller-numbers-after-self
3466-number-of-subarrays-with-and-value-of-k
3789-maximize-subarrays-after-removing-one-conflicting-pair
3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii

Rolling Hash

0214-shortest-palindrome
1508-longest-happy-prefix

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string
0214-shortest-palindrome
0459-repeated-substring-pattern
0812-rotate-string
1508-longest-happy-prefix

Hash Function

0214-shortest-palindrome
1508-longest-happy-prefix
2079-delete-duplicate-folders-in-system

Greedy

0011-container-with-most-water
0134-gas-station
0409-longest-palindrome
0502-ipo
0611-valid-triangle-number
0778-reorganize-string
0797-rabbits-in-forest
0902-minimum-number-of-refueling-stops
0957-minimum-add-to-make-parentheses-valid
1018-largest-perimeter-triangle
1448-maximum-69-number
1478-maximum-number-of-events-that-can-be-attended
1489-pizza-with-3n-slices
1503-reducing-dishes
1529-max-difference-you-can-get-from-changing-an-integer
1612-avoid-flood-in-the-city
1690-maximum-length-of-subarray-with-positive-product
1818-maximum-score-from-removing-substrings
1829-maximum-units-on-a-truck
1938-minimum-operations-to-make-the-array-increasing
1975-maximum-matrix-sum
2199-two-furthest-houses-with-different-colors
2237-longest-palindrome-by-concatenating-two-letter-words
2362-minimum-rounds-to-complete-all-tasks
2387-partition-array-such-that-maximum-difference-is-k
2469-longest-subsequence-with-limited-sum
2497-maximum-matching-of-players-with-trainers
2661-smallest-missing-non-negative-integer-after-operations
2689-rearranging-fruits
3143-longest-unequal-adjacent-groups-subsequence-i
3171-minimum-equal-sum-of-two-arrays-after-replacing-zeros
3241-divide-array-into-arrays-with-max-difference
3360-minimum-deletions-to-make-string-k-special
3620-maximum-number-of-distinct-elements-after-operations
3738-make-array-non-decreasing
3741-reschedule-meetings-for-maximum-free-time-ii
3743-reschedule-meetings-for-maximum-free-time-i
3788-maximum-unique-subarray-sum-after-deletion
3834-minimum-operations-to-convert-all-elements-to-zero

Graph

0133-clone-graph
0207-course-schedule
0210-course-schedule-ii
0399-evaluate-division
0801-is-graph-bipartite
0813-all-paths-from-source-to-target
0820-find-eventual-safe-states
1039-find-the-town-judge
2439-longest-cycle-in-a-graph
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii

Topological Sort

0207-course-schedule
0210-course-schedule-ii
0820-find-eventual-safe-states
2439-longest-cycle-in-a-graph

Bit Manipulation

0029-divide-two-integers
0067-add-binary
0090-subsets-ii
0136-single-number
0137-single-number-ii
0190-reverse-bits
0201-bitwise-and-of-numbers-range
0231-power-of-two
0260-single-number-iii
0268-missing-number
0318-maximum-product-of-word-lengths
0342-power-of-four
0421-maximum-xor-of-two-numbers-in-an-array
0756-pyramid-transition-matrix
0895-shortest-path-to-get-all-keys
0934-bitwise-ors-of-subarrays
1018-binary-prefix-divisible-by-5
1022-unique-paths-iii
1037-minimum-number-of-k-consecutive-bit-flips
1435-xor-queries-of-a-subarray
1826-maximum-xor-with-an-element-from-array
1930-unique-length-3-palindromic-subsequences
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
2594-count-pairs-of-similar-strings
3093-sum-of-values-at-indices-with-k-set-bits
3466-number-of-subarrays-with-and-value-of-k
3600-find-the-k-th-character-in-string-game-i
3601-find-the-k-th-character-in-string-game-ii
3676-smallest-number-with-all-set-bits

Union Find

0130-surrounded-regions
0200-number-of-islands
0399-evaluate-division
0801-is-graph-bipartite
1058-lexicographically-smallest-equivalent-string

Divide and Conquer

0004-median-of-two-sorted-arrays
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
0109-convert-sorted-list-to-binary-search-tree
0148-sort-list
0190-reverse-bits
0215-kth-largest-element-in-an-array
0315-count-of-smaller-numbers-after-self
0772-construct-quad-tree
0954-maximum-sum-circular-subarray

Merge Sort

0148-sort-list
0315-count-of-smaller-numbers-after-self

Ordered Set

0315-count-of-smaller-numbers-after-self
0456-132-pattern
3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii

Trie

0139-word-break
0140-word-break-ii
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0212-word-search-ii
0386-lexicographical-numbers
0421-maximum-xor-of-two-numbers-in-an-array
0472-concatenated-words
0692-top-k-frequent-words
0720-longest-word-in-dictionary
1350-remove-sub-folders-from-the-filesystem
1826-maximum-xor-with-an-element-from-array
2079-delete-duplicate-folders-in-system

Memoization

0070-climbing-stairs
0139-word-break
0140-word-break-ii
1013-fibonacci-number
2028-the-earliest-and-latest-rounds-where-players-compete
3239-minimum-number-of-operations-to-make-x-and-y-equal

Simulation

0043-multiply-strings
0067-add-binary
0498-diagonal-traverse
1642-water-bottles
1708-design-parking-system
1929-concatenation-of-array
2048-build-array-from-permutation
2132-convert-1d-array-into-2d-array
2137-final-value-of-variable-after-performing-operations
2169-simple-bank-system
2260-divide-a-string-into-groups-of-size-k
2271-rearrange-array-elements-by-sign
2324-find-triangular-sum-of-an-array
2343-count-unguarded-cells-in-the-grid
2411-spiral-matrix-iv
2479-meeting-rooms-iii
2662-check-knight-tour-configuration
3516-design-neighbor-sum-service
3566-find-the-sequence-of-strings-appeared-on-the-screen
3600-find-the-k-th-character-in-string-game-i
3616-make-array-elements-equal-to-zero
3768-check-if-digits-are-equal-in-string-after-operations-i
3790-fruits-into-baskets-ii
3893-generate-tag-for-video-caption

Counting

0387-first-unique-character-in-a-string
0594-longest-harmonious-subsequence
0692-top-k-frequent-words
0778-reorganize-string
0900-reordered-power-of-2
1034-subarrays-with-k-different-integers
1227-number-of-equivalent-domino-pairs
1510-find-lucky-integer-in-an-array
1708-design-parking-system
2129-number-of-pairs-of-interchangeable-rectangles
2174-next-greater-numerically-balanced-number
2237-longest-palindrome-by-concatenating-two-letter-words
2362-minimum-rounds-to-complete-all-tasks
2594-count-pairs-of-similar-strings
3242-count-elements-with-maximum-frequency
3360-minimum-deletions-to-make-string-k-special
3437-maximum-total-damage-with-spell-casting
3583-count-special-triplets
3629-total-characters-in-string-after-transformations-i
3753-maximum-difference-between-even-and-odd-frequency-i
3754-maximum-manhattan-distance-after-k-changes
3872-find-most-frequent-vowel-and-consonant

Queue

0239-sliding-window-maximum
0387-first-unique-character-in-a-string
0892-shortest-subarray-with-sum-at-least-k
0954-maximum-sum-circular-subarray
1037-minimum-number-of-k-consecutive-bit-flips
2449-maximum-number-of-robots-within-budget

Monotonic Queue

0239-sliding-window-maximum
0892-shortest-subarray-with-sum-at-least-k
0954-maximum-sum-circular-subarray
2449-maximum-number-of-robots-within-budget

Heap (Priority Queue)

0215-kth-largest-element-in-an-array
0239-sliding-window-maximum
0295-find-median-from-data-stream
0373-find-k-pairs-with-smallest-sums
0378-kth-smallest-element-in-a-sorted-matrix
0502-ipo
0692-top-k-frequent-words
0778-reorganize-string
0892-shortest-subarray-with-sum-at-least-k
0902-minimum-number-of-refueling-stops
1127-last-stone-weight
1478-maximum-number-of-events-that-can-be-attended
1489-pizza-with-3n-slices
1612-avoid-flood-in-the-city
2204-find-subsequence-of-length-k-with-the-largest-sum
2267-minimum-difference-in-sums-after-removal-of-elements
2449-maximum-number-of-robots-within-budget
2479-meeting-rooms-iii
3610-find-x-sum-of-all-k-long-subarrays-i
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii

Shortest Path

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

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0024-swap-nodes-in-pairs
0050-powx-n
0060-permutation-sequence
0143-reorder-list
0224-basic-calculator
0231-power-of-two
0234-palindrome-linked-list
0326-power-of-three
0342-power-of-four
0394-decode-string
1013-fibonacci-number
3600-find-the-k-th-character-in-string-game-i
3601-find-the-k-th-character-in-string-game-ii

Database

0175-combine-two-tables
0176-second-highest-salary
0197-rising-temperature
1135-customers-who-bought-all-products
1179-game-play-analysis-i
1827-invalid-tweets

Doubly-Linked List

0146-lru-cache
0460-lfu-cache

Bucket Sort

0692-top-k-frequent-words

Brainteaser

2481-strictly-palindromic-number
2503-longest-subarray-with-maximum-bitwise-and
3577-count-the-number-of-computer-unlocking-permutations

Number Theory

2129-number-of-pairs-of-interchangeable-rectangles
3768-check-if-digits-are-equal-in-string-after-operations-i

Probability and Statistics

0826-soup-servings
0867-new-21-game

Data Stream

0295-find-median-from-data-stream

Geometry

0149-max-points-on-a-line
0830-largest-triangle-area
3278-find-the-number-of-ways-to-place-people-i

Iterator

0173-binary-search-tree-iterator

Quickselect

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

Combinatorics

2324-find-triangular-sum-of-an-array
3577-count-the-number-of-computer-unlocking-permutations
3768-check-if-digits-are-equal-in-string-after-operations-i