Leetcode-Solutions

Collection of LeetCode questions to ace the coding interview!!

Array

0347-top-k-frequent-elements
1137-height-checker

Sorting

0347-top-k-frequent-elements
1137-height-checker

Counting Sort

0347-top-k-frequent-elements
1137-height-checker

Tree

1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree

Depth-First Search

1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree

Binary Search Tree

1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree

Binary Tree

1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree

Hash Table

0347-top-k-frequent-elements

Divide and Conquer

0347-top-k-frequent-elements
1285-balance-a-binary-search-tree

Heap (Priority Queue)

0347-top-k-frequent-elements

Bucket Sort

0347-top-k-frequent-elements

Quickselect

0347-top-k-frequent-elements

Greedy

1285-balance-a-binary-search-tree

LeetCode Topics

Depth-First Search

0099-recover-binary-search-tree
0101-symmetric-tree
0133-clone-graph
0145-binary-tree-postorder-traversal
0210-course-schedule-ii
0211-design-add-and-search-words-data-structure
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0297-serialize-and-deserialize-binary-tree
0386-lexicographical-numbers
0515-find-largest-value-in-each-tree-row
0572-subtree-of-another-tree
0684-redundant-connection
0776-n-ary-tree-postorder-traversal
0820-find-eventual-safe-states
0854-making-a-large-island
0984-most-stones-removed-with-same-row-or-column
0988-flip-equivalent-binary-trees
0999-regions-cut-by-slashes
1350-remove-sub-folders-from-the-filesystem
1396-count-servers-that-communicate
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1484-linked-list-in-binary-tree
1544-count-good-nodes-in-binary-tree
1558-course-schedule-iv
1653-number-of-good-leaf-nodes-pairs
2035-count-sub-islands
2201-valid-arrangement-of-pairs
2217-step-by-step-directions-from-a-binary-tree-node-to-another
2246-maximum-employees-to-be-invited-to-a-meeting
2493-reverse-odd-levels-of-binary-tree
2677-cousins-in-binary-tree-ii
2764-maximum-number-of-fish-in-a-grid
3058-maximum-number-of-k-divisible-components

Breadth-First Search

0101-symmetric-tree
0102-binary-tree-level-order-traversal
0127-word-ladder
0133-clone-graph
0210-course-schedule-ii
0226-invert-binary-tree
0297-serialize-and-deserialize-binary-tree
0322-coin-change
0407-trapping-rain-water-ii
0515-find-largest-value-in-each-tree-row
0684-redundant-connection
0787-sliding-puzzle
0820-find-eventual-safe-states
0854-making-a-large-island
0999-regions-cut-by-slashes
1396-count-servers-that-communicate
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1484-linked-list-in-binary-tree
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1544-count-good-nodes-in-binary-tree
1558-course-schedule-iv
1731-even-odd-tree
1876-map-of-highest-peak
2035-count-sub-islands
2171-second-minimum-time-to-reach-destination
2375-minimum-obstacle-removal-to-reach-corner
2493-reverse-odd-levels-of-binary-tree
2558-minimum-number-of-operations-to-sort-a-binary-tree-by-level
2583-divide-nodes-into-the-maximum-number-of-groups
2646-kth-largest-sum-in-a-binary-tree
2677-cousins-in-binary-tree-ii
2711-minimum-time-to-visit-a-cell-in-a-grid
2764-maximum-number-of-fish-in-a-grid
3517-shortest-distance-after-road-addition-queries-i

Graph

0133-clone-graph
0210-course-schedule-ii
0684-redundant-connection
0820-find-eventual-safe-states
0984-most-stones-removed-with-same-row-or-column
1325-path-with-maximum-probability
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1456-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1558-course-schedule-iv
1701-remove-max-number-of-edges-to-keep-graph-fully-traversable
1738-maximal-network-rank
2171-second-minimum-time-to-reach-destination
2201-valid-arrangement-of-pairs
2246-maximum-employees-to-be-invited-to-a-meeting
2375-minimum-obstacle-removal-to-reach-corner
2583-divide-nodes-into-the-maximum-number-of-groups
2711-minimum-time-to-visit-a-cell-in-a-grid
2803-modify-graph-edge-weights
3189-find-champion-ii
3235-minimum-cost-to-convert-string-i
3517-shortest-distance-after-road-addition-queries-i

Topological Sort

0210-course-schedule-ii
0820-find-eventual-safe-states
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1558-course-schedule-iv
2246-maximum-employees-to-be-invited-to-a-meeting

Union Find

0128-longest-consecutive-sequence
0684-redundant-connection
0854-making-a-large-island
0984-most-stones-removed-with-same-row-or-column
0999-regions-cut-by-slashes
1396-count-servers-that-communicate
1701-remove-max-number-of-edges-to-keep-graph-fully-traversable
2035-count-sub-islands
2583-divide-nodes-into-the-maximum-number-of-groups
2764-maximum-number-of-fish-in-a-grid
3219-make-lexicographically-smallest-array-by-swapping-elements

Array

0001-two-sum
0004-median-of-two-sorted-arrays
0011-container-with-most-water
0027-remove-element
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0036-valid-sudoku
0039-combination-sum
0040-combination-sum-ii
0041-first-missing-positive
0048-rotate-image
0053-maximum-subarray
0054-spiral-matrix
0055-jump-game
0056-merge-intervals
0057-insert-interval
0064-minimum-path-sum
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0075-sort-colors
0084-largest-rectangle-in-histogram
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0108-convert-sorted-array-to-binary-search-tree
0118-pascals-triangle
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0128-longest-consecutive-sequence
0139-word-break
0152-maximum-product-subarray
0153-find-minimum-in-rotated-sorted-array
0169-majority-element
0179-largest-number
0198-house-robber
0204-count-primes
0209-minimum-size-subarray-sum
0212-word-search-ii
0215-kth-largest-element-in-an-array
0229-majority-element-ii
0239-sliding-window-maximum
0240-search-a-2d-matrix-ii
0274-h-index
0322-coin-change
0347-top-k-frequent-elements
0350-intersection-of-two-arrays-ii
0380-insert-delete-getrandom-o1
0407-trapping-rain-water-ii
0494-target-sum
0498-diagonal-traverse
0539-minimum-time-difference
0621-task-scheduler
0624-maximum-distance-in-arrays
0632-smallest-range-covering-elements-from-k-lists
0719-find-k-th-smallest-pair-distance
0729-my-calendar-i
0731-my-calendar-ii
0780-max-chunks-to-make-sorted
0787-sliding-puzzle
0816-design-hashset
0854-making-a-large-island
0859-design-circular-deque
0870-magic-squares-in-grid
0890-lemonade-change
0892-shortest-subarray-with-sum-at-least-k
0906-walking-robot-simulation
0907-koko-eating-bananas
0912-random-pick-with-weight
0921-spiral-matrix-iii
0948-sort-an-array
0952-word-subsets
0999-regions-cut-by-slashes
1002-maximum-width-ramp
1014-k-closest-points-to-origin
1025-minimum-cost-for-tickets
1046-max-consecutive-ones-iii
1147-flip-columns-for-maximum-number-of-equal-rows
1196-filling-bookcase-shelves
1240-stone-game-ii
1256-rank-transform-of-an-array
1293-three-consecutive-odds
1325-path-with-maximum-probability
1333-sort-the-jumbled-numbers
1350-remove-sub-folders-from-the-filesystem
1396-count-servers-that-communicate
1402-count-square-submatrices-with-all-ones
1435-xor-queries-of-a-subarray
1468-check-if-n-and-its-double-exist
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1487-cinema-seat-allocation
1496-lucky-numbers-in-a-matrix
1497-design-a-stack-with-increment-operation
1511-count-number-of-teams
1524-string-matching-in-an-array
1556-make-two-arrays-equal-by-reversing-subarrays
1570-final-prices-with-a-special-discount-in-a-shop
1615-range-sum-of-sorted-subarray-sums
1616-minimum-difference-between-largest-and-smallest-value-in-three-moves
1620-check-if-array-pairs-are-divisible-by-k
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1694-make-sum-divisible-by-p
1700-minimum-time-to-make-rope-colorful
1711-find-valid-matrix-given-row-and-column-sums
1720-crawler-log-folder
1741-sort-array-by-increasing-frequency
1766-minimum-number-of-removals-to-make-mountain-array
1786-count-the-number-of-consistent-strings
1803-average-waiting-time
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
1901-equal-sum-arrays-with-minimum-number-of-operations
1917-maximum-average-pass-ratio
1923-sentence-similarity-iii
1940-maximum-xor-for-each-query
1951-find-the-winner-of-the-circular-game
1972-rotating-the-box
2006-find-the-student-that-will-replace-the-chalk
2035-count-sub-islands
2054-the-number-of-the-smallest-unoccupied-chair
2067-maximum-number-of-points-with-cost
2089-maximum-matrix-sum
2132-convert-1d-array-into-2d-array
2145-grid-game
2155-find-missing-observations
2163-kth-distinct-string-in-an-array
2170-count-number-of-maximum-bitwise-or-subsets
2179-most-beautiful-item-for-each-query
2188-minimized-maximum-of-products-distributed-to-any-store
2232-adding-spaces-to-a-string
2255-minimum-swaps-to-group-all-1s-together-ii
2306-create-binary-tree-from-descriptions
2343-count-unguarded-cells-in-the-grid
2356-largest-combination-with-bitwise-and-greater-than-zero
2358-number-of-ways-to-split-array
2375-minimum-obstacle-removal-to-reach-corner
2411-spiral-matrix-iv
2465-shifting-letters-ii
2488-divide-intervals-into-minimum-number-of-groups
2494-sum-of-prefix-scores-of-strings
2502-sort-the-people
2503-longest-subarray-with-maximum-bitwise-and
2533-bitwise-xor-of-all-pairings
2552-maximum-sum-of-distinct-subarrays-with-length-k
2554-minimum-total-distance-traveled
2616-maximal-score-after-applying-k-operations
2640-maximum-number-of-integers-to-choose-from-a-range-i
2685-first-completely-painted-row-or-column
2691-count-vowel-strings-in-ranges
2692-take-gifts-from-the-richest-pile
2695-find-score-of-an-array-after-marking-all-elements
2699-count-the-number-of-fair-pairs
2711-minimum-time-to-visit-a-cell-in-a-grid
2716-prime-subtraction-operation
2727-number-of-senior-citizens
2755-extra-characters-in-a-string
2764-maximum-number-of-fish-in-a-grid
2766-find-the-prefix-common-array-of-two-arrays
2792-neighboring-bitwise-xor
2794-maximum-number-of-moves-in-a-grid
2846-robot-collisions
3181-find-building-where-alice-and-bob-can-meet
3219-make-lexicographically-smallest-array-by-swapping-elements
3235-minimum-cost-to-convert-string-i
3291-find-if-array-can-be-sorted
3309-count-prefix-and-suffix-pairs-i
3329-find-the-length-of-the-longest-common-prefix
3372-longest-strictly-increasing-or-strictly-decreasing-subarray
3427-special-array-ii
3429-special-array-i
3501-delete-nodes-from-linked-list-present-in-array
3517-shortest-distance-after-road-addition-queries-i
3522-find-the-power-of-k-size-subarrays-i
3555-final-array-state-after-k-multiplication-operations-i

Hash Table

0001-two-sum
0012-integer-to-roman
0017-letter-combinations-of-a-phone-number
0036-valid-sudoku
0041-first-missing-positive
0073-set-matrix-zeroes
0076-minimum-window-substring
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0127-word-ladder
0128-longest-consecutive-sequence
0133-clone-graph
0139-word-break
0141-linked-list-cycle
0146-lru-cache
0160-intersection-of-two-linked-lists
0169-majority-element
0202-happy-number
0208-implement-trie-prefix-tree
0229-majority-element-ii
0264-ugly-number-ii
0347-top-k-frequent-elements
0350-intersection-of-two-arrays-ii
0380-insert-delete-getrandom-o1
0424-longest-repeating-character-replacement
0432-all-oone-data-structure
0621-task-scheduler
0632-smallest-range-covering-elements-from-k-lists
0726-number-of-atoms
0816-design-hashset
0870-magic-squares-in-grid
0906-walking-robot-simulation
0920-uncommon-words-from-two-sentences
0952-word-subsets
0984-most-stones-removed-with-same-row-or-column
0999-regions-cut-by-slashes
1023-time-based-key-value-store
1147-flip-columns-for-maximum-number-of-equal-rows
1256-rank-transform-of-an-array
1468-check-if-n-and-its-double-exist
1473-find-the-longest-substring-containing-vowels-in-even-counts
1487-cinema-seat-allocation
1502-construct-k-palindrome-strings
1556-make-two-arrays-equal-by-reversing-subarrays
1620-check-if-array-pairs-are-divisible-by-k
1694-make-sum-divisible-by-p
1715-split-a-string-into-the-max-number-of-unique-substrings
1741-sort-array-by-increasing-frequency
1770-minimum-deletions-to-make-character-frequencies-unique
1786-count-the-number-of-consistent-strings
1901-equal-sum-arrays-with-minimum-number-of-operations
1915-check-if-one-string-swap-can-make-strings-equal
2054-the-number-of-the-smallest-unoccupied-chair
2059-unique-length-3-palindromic-subsequences
2163-kth-distinct-string-in-an-array
2300-construct-string-with-repeat-limit
2306-create-binary-tree-from-descriptions
2356-largest-combination-with-bitwise-and-greater-than-zero
2502-sort-the-people
2552-maximum-sum-of-distinct-subarrays-with-length-k
2599-take-k-of-each-character-from-left-and-right
2640-maximum-number-of-integers-to-choose-from-a-range-i
2677-cousins-in-binary-tree-ii
2685-first-completely-painted-row-or-column
2695-find-score-of-an-array-after-marking-all-elements
2755-extra-characters-in-a-string
2766-find-the-prefix-common-array-of-two-arrays
3276-minimum-number-of-pushes-to-type-word-ii
3329-find-the-length-of-the-longest-common-prefix
3455-minimum-length-of-string-after-operations
3501-delete-nodes-from-linked-list-present-in-array

Matrix

0036-valid-sudoku
0048-rotate-image
0054-spiral-matrix
0064-minimum-path-sum
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0212-word-search-ii
0240-search-a-2d-matrix-ii
0407-trapping-rain-water-ii
0498-diagonal-traverse
0787-sliding-puzzle
0854-making-a-large-island
0870-magic-squares-in-grid
0921-spiral-matrix-iii
0999-regions-cut-by-slashes
1147-flip-columns-for-maximum-number-of-equal-rows
1396-count-servers-that-communicate
1402-count-square-submatrices-with-all-ones
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1496-lucky-numbers-in-a-matrix
1711-find-valid-matrix-given-row-and-column-sums
1876-map-of-highest-peak
1972-rotating-the-box
2035-count-sub-islands
2089-maximum-matrix-sum
2132-convert-1d-array-into-2d-array
2145-grid-game
2343-count-unguarded-cells-in-the-grid
2375-minimum-obstacle-removal-to-reach-corner
2411-spiral-matrix-iv
2685-first-completely-painted-row-or-column
2711-minimum-time-to-visit-a-cell-in-a-grid
2764-maximum-number-of-fish-in-a-grid
2794-maximum-number-of-moves-in-a-grid

Two Pointers

0005-longest-palindromic-substring
0011-container-with-most-water
0019-remove-nth-node-from-end-of-list
0027-remove-element
0075-sort-colors
0086-partition-list
0141-linked-list-cycle
0143-reorder-list
0151-reverse-words-in-a-string
0160-intersection-of-two-linked-lists
0202-happy-number
0295-find-median-from-data-stream
0350-intersection-of-two-arrays-ii
0557-reverse-words-in-a-string-iii
0680-valid-palindrome-ii
0719-find-k-th-smallest-pair-distance
0874-backspace-string-compare
0908-middle-of-the-linked-list
1468-check-if-n-and-its-double-exist
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
1615-range-sum-of-sorted-subarray-sums
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1923-sentence-similarity-iii
1972-rotating-the-box
2095-minimum-number-of-swaps-to-make-the-string-balanced
2232-adding-spaces-to-a-string
2414-move-pieces-to-obtain-a-string
2488-divide-intervals-into-minimum-number-of-groups
2699-count-the-number-of-fair-pairs
3195-separate-black-and-white-balls

Binary Search

0004-median-of-two-sorted-arrays
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0069-sqrtx
0074-search-a-2d-matrix
0153-find-minimum-in-rotated-sorted-array
0209-minimum-size-subarray-sum
0240-search-a-2d-matrix-ii
0350-intersection-of-two-arrays-ii
0719-find-k-th-smallest-pair-distance
0729-my-calendar-i
0731-my-calendar-ii
0892-shortest-subarray-with-sum-at-least-k
0907-koko-eating-bananas
0912-random-pick-with-weight
1023-time-based-key-value-store
1046-max-consecutive-ones-iii
1468-check-if-n-and-its-double-exist
1615-range-sum-of-sorted-subarray-sums
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1766-minimum-number-of-removals-to-make-mountain-array
2006-find-the-student-that-will-replace-the-chalk
2179-most-beautiful-item-for-each-query
2188-minimized-maximum-of-products-distributed-to-any-store
2640-maximum-number-of-integers-to-choose-from-a-range-i
2699-count-the-number-of-fair-pairs
2716-prime-subtraction-operation
3181-find-building-where-alice-and-bob-can-meet
3427-special-array-ii

Sorting

0056-merge-intervals
0075-sort-colors
0169-majority-element
0179-largest-number
0215-kth-largest-element-in-an-array
0229-majority-element-ii
0274-h-index
0295-find-median-from-data-stream
0347-top-k-frequent-elements
0350-intersection-of-two-arrays-ii
0539-minimum-time-difference
0621-task-scheduler
0632-smallest-range-covering-elements-from-k-lists
0719-find-k-th-smallest-pair-distance
0726-number-of-atoms
0780-max-chunks-to-make-sorted
0948-sort-an-array
1014-k-closest-points-to-origin
1256-rank-transform-of-an-array
1333-sort-the-jumbled-numbers
1468-check-if-n-and-its-double-exist
1556-make-two-arrays-equal-by-reversing-subarrays
1615-range-sum-of-sorted-subarray-sums
1616-minimum-difference-between-largest-and-smallest-value-in-three-moves
1741-sort-array-by-increasing-frequency
1770-minimum-deletions-to-make-character-frequencies-unique
2179-most-beautiful-item-for-each-query
2488-divide-intervals-into-minimum-number-of-groups
2502-sort-the-people
2554-minimum-total-distance-traveled
2640-maximum-number-of-integers-to-choose-from-a-range-i
2646-kth-largest-sum-in-a-binary-tree
2695-find-score-of-an-array-after-marking-all-elements
2699-count-the-number-of-fair-pairs
2846-robot-collisions
3219-make-lexicographically-smallest-array-by-swapping-elements
3276-minimum-number-of-pushes-to-type-word-ii
3291-find-if-array-can-be-sorted

Greedy

0011-container-with-most-water
0055-jump-game
0122-best-time-to-buy-and-sell-stock-ii
0179-largest-number
0316-remove-duplicate-letters
0402-remove-k-digits
0621-task-scheduler
0624-maximum-distance-in-arrays
0632-smallest-range-covering-elements-from-k-lists
0670-maximum-swap
0678-valid-parenthesis-string
0680-valid-palindrome-ii
0780-max-chunks-to-make-sorted
0890-lemonade-change
0957-minimum-add-to-make-parentheses-valid
1304-longest-happy-string
1487-cinema-seat-allocation
1502-construct-k-palindrome-strings
1616-minimum-difference-between-largest-and-smallest-value-in-three-moves
1700-minimum-time-to-make-rope-colorful
1711-find-valid-matrix-given-row-and-column-sums
1766-minimum-number-of-removals-to-make-mountain-array
1770-minimum-deletions-to-make-character-frequencies-unique
1818-maximum-score-from-removing-substrings
1901-equal-sum-arrays-with-minimum-number-of-operations
1917-maximum-average-pass-ratio
2089-maximum-matrix-sum
2095-minimum-number-of-swaps-to-make-the-string-balanced
2221-check-if-a-parentheses-string-can-be-valid
2300-construct-string-with-repeat-limit
2488-divide-intervals-into-minimum-number-of-groups
2509-minimize-xor
2616-maximal-score-after-applying-k-operations
2640-maximum-number-of-integers-to-choose-from-a-range-i
2716-prime-subtraction-operation
3195-separate-black-and-white-balls
3276-minimum-number-of-pushes-to-type-word-ii

Math

0002-add-two-numbers
0007-reverse-integer
0012-integer-to-roman
0043-multiply-strings
0048-rotate-image
0050-powx-n
0069-sqrtx
0070-climbing-stairs
0202-happy-number
0204-count-primes
0224-basic-calculator
0241-different-ways-to-add-parentheses
0264-ugly-number-ii
0273-integer-to-english-words
0371-sum-of-two-integers
0380-insert-delete-getrandom-o1
0539-minimum-time-difference
0564-find-the-closest-palindrome
0592-fraction-addition-and-subtraction
0650-2-keys-keyboard
0670-maximum-swap
0870-magic-squares-in-grid
0912-random-pick-with-weight
1014-k-closest-points-to-origin
1240-stone-game-ii
1642-water-bottles
1951-find-the-winner-of-the-circular-game
2155-find-missing-observations
2645-pass-the-pillow
2716-prime-subtraction-operation
2903-insert-greatest-common-divisors-in-linked-list
3555-final-array-state-after-k-multiplication-operations-i

Simulation

0043-multiply-strings
0054-spiral-matrix
0498-diagonal-traverse
0592-fraction-addition-and-subtraction
0874-backspace-string-compare
0906-walking-robot-simulation
0921-spiral-matrix-iii
1642-water-bottles
1667-find-kth-bit-in-nth-binary-string
1803-average-waiting-time
1951-find-the-winner-of-the-circular-game
2006-find-the-student-that-will-replace-the-chalk
2076-sum-of-digits-of-string-after-convert
2132-convert-1d-array-into-2d-array
2155-find-missing-observations
2232-adding-spaces-to-a-string
2343-count-unguarded-cells-in-the-grid
2411-spiral-matrix-iv
2645-pass-the-pillow
2692-take-gifts-from-the-richest-pile
2695-find-score-of-an-array-after-marking-all-elements
2800-minimum-string-length-after-removing-substrings
2846-robot-collisions
3555-final-array-state-after-k-multiplication-operations-i

Recursion

0002-add-two-numbers
0010-regular-expression-matching
0021-merge-two-sorted-lists
0050-powx-n
0143-reorder-list
0224-basic-calculator
0241-different-ways-to-add-parentheses
0273-integer-to-english-words
0394-decode-string
1197-parsing-a-boolean-expression
1667-find-kth-bit-in-nth-binary-string
1951-find-the-winner-of-the-circular-game

Queue

0239-sliding-window-maximum
0859-design-circular-deque
0892-shortest-subarray-with-sum-at-least-k
1951-find-the-winner-of-the-circular-game

String

0005-longest-palindromic-substring
0008-string-to-integer-atoi
0010-regular-expression-matching
0012-integer-to-roman
0014-longest-common-prefix
0017-letter-combinations-of-a-phone-number
0043-multiply-strings
0076-minimum-window-substring
0127-word-ladder
0139-word-break
0151-reverse-words-in-a-string
0179-largest-number
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0212-word-search-ii
0214-shortest-palindrome
0224-basic-calculator
0241-different-ways-to-add-parentheses
0273-integer-to-english-words
0297-serialize-and-deserialize-binary-tree
0316-remove-duplicate-letters
0394-decode-string
0402-remove-k-digits
0424-longest-repeating-character-replacement
0539-minimum-time-difference
0557-reverse-words-in-a-string-iii
0564-find-the-closest-palindrome
0592-fraction-addition-and-subtraction
0664-strange-printer
0678-valid-parenthesis-string
0680-valid-palindrome-ii
0726-number-of-atoms
0812-rotate-string
0874-backspace-string-compare
0920-uncommon-words-from-two-sentences
0952-word-subsets
0957-minimum-add-to-make-parentheses-valid
1023-time-based-key-value-store
1197-parsing-a-boolean-expression
1250-longest-common-subsequence
1298-reverse-substrings-between-each-pair-of-parentheses
1302-delete-characters-to-make-fancy-string
1304-longest-happy-string
1350-remove-sub-folders-from-the-filesystem
1473-find-the-longest-substring-containing-vowels-in-even-counts
1502-construct-k-palindrome-strings
1524-string-matching-in-an-array
1537-maximum-score-after-splitting-a-string
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
1667-find-kth-bit-in-nth-binary-string
1700-minimum-time-to-make-rope-colorful
1715-split-a-string-into-the-max-number-of-unique-substrings
1720-crawler-log-folder
1756-minimum-deletions-to-make-string-balanced
1770-minimum-deletions-to-make-character-frequencies-unique
1786-count-the-number-of-consistent-strings
1818-maximum-score-from-removing-substrings
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1915-check-if-one-string-swap-can-make-strings-equal
1923-sentence-similarity-iii
2059-unique-length-3-palindromic-subsequences
2076-sum-of-digits-of-string-after-convert
2095-minimum-number-of-swaps-to-make-the-string-balanced
2163-kth-distinct-string-in-an-array
2217-step-by-step-directions-from-a-binary-tree-node-to-another
2221-check-if-a-parentheses-string-can-be-valid
2232-adding-spaces-to-a-string
2300-construct-string-with-repeat-limit
2414-move-pieces-to-obtain-a-string
2465-shifting-letters-ii
2494-sum-of-prefix-scores-of-strings
2502-sort-the-people
2580-circular-sentence
2599-take-k-of-each-character-from-left-and-right
2691-count-vowel-strings-in-ranges
2727-number-of-senior-citizens
2755-extra-characters-in-a-string
2800-minimum-string-length-after-removing-substrings
3174-minimum-number-of-changes-to-make-binary-string-beautiful
3195-separate-black-and-white-balls
3235-minimum-cost-to-convert-string-i
3276-minimum-number-of-pushes-to-type-word-ii
3309-count-prefix-and-suffix-pairs-i
3329-find-the-length-of-the-longest-common-prefix
3455-minimum-length-of-string-after-operations

Stack

0084-largest-rectangle-in-histogram
0143-reorder-list
0145-binary-tree-postorder-traversal
0173-binary-search-tree-iterator
0224-basic-calculator
0316-remove-duplicate-letters
0394-decode-string
0402-remove-k-digits
0678-valid-parenthesis-string
0726-number-of-atoms
0776-n-ary-tree-postorder-traversal
0780-max-chunks-to-make-sorted
0874-backspace-string-compare
0957-minimum-add-to-make-parentheses-valid
1002-maximum-width-ramp
1197-parsing-a-boolean-expression
1298-reverse-substrings-between-each-pair-of-parentheses
1497-design-a-stack-with-increment-operation
1570-final-prices-with-a-special-discount-in-a-shop
1679-shortest-subarray-to-be-removed-to-make-array-sorted
1720-crawler-log-folder
1756-minimum-deletions-to-make-string-balanced
1818-maximum-score-from-removing-substrings
2095-minimum-number-of-swaps-to-make-the-string-balanced
2221-check-if-a-parentheses-string-can-be-valid
2800-minimum-string-length-after-removing-substrings
2846-robot-collisions
3181-find-building-where-alice-and-bob-can-meet

Tree

0099-recover-binary-search-tree
0101-symmetric-tree
0102-binary-tree-level-order-traversal
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0108-convert-sorted-array-to-binary-search-tree
0145-binary-tree-postorder-traversal
0173-binary-search-tree-iterator
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0297-serialize-and-deserialize-binary-tree
0515-find-largest-value-in-each-tree-row
0572-subtree-of-another-tree
0776-n-ary-tree-postorder-traversal
0789-kth-largest-element-in-a-stream
0988-flip-equivalent-binary-trees
1484-linked-list-in-binary-tree
1544-count-good-nodes-in-binary-tree
1653-number-of-good-leaf-nodes-pairs
1731-even-odd-tree
2217-step-by-step-directions-from-a-binary-tree-node-to-another
2306-create-binary-tree-from-descriptions
2493-reverse-odd-levels-of-binary-tree
2558-minimum-number-of-operations-to-sort-a-binary-tree-by-level
2646-kth-largest-sum-in-a-binary-tree
2677-cousins-in-binary-tree-ii
3058-maximum-number-of-k-divisible-components

Binary Tree

0099-recover-binary-search-tree
0101-symmetric-tree
0102-binary-tree-level-order-traversal
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0108-convert-sorted-array-to-binary-search-tree
0145-binary-tree-postorder-traversal
0173-binary-search-tree-iterator
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0297-serialize-and-deserialize-binary-tree
0515-find-largest-value-in-each-tree-row
0572-subtree-of-another-tree
0789-kth-largest-element-in-a-stream
0988-flip-equivalent-binary-trees
1484-linked-list-in-binary-tree
1544-count-good-nodes-in-binary-tree
1653-number-of-good-leaf-nodes-pairs
1731-even-odd-tree
2217-step-by-step-directions-from-a-binary-tree-node-to-another
2306-create-binary-tree-from-descriptions
2493-reverse-odd-levels-of-binary-tree
2558-minimum-number-of-operations-to-sort-a-binary-tree-by-level
2646-kth-largest-sum-in-a-binary-tree
2677-cousins-in-binary-tree-ii

Sliding Window

0076-minimum-window-substring
0209-minimum-size-subarray-sum
0239-sliding-window-maximum
0424-longest-repeating-character-replacement
0632-smallest-range-covering-elements-from-k-lists
0892-shortest-subarray-with-sum-at-least-k
1046-max-consecutive-ones-iii
2255-minimum-swaps-to-group-all-1s-together-ii
2552-maximum-sum-of-distinct-subarrays-with-length-k
2599-take-k-of-each-character-from-left-and-right
3522-find-the-power-of-k-size-subarrays-i

Divide and Conquer

0004-median-of-two-sorted-arrays
0023-merge-k-sorted-lists
0053-maximum-subarray
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0108-convert-sorted-array-to-binary-search-tree
0169-majority-element
0190-reverse-bits
0191-number-of-1-bits
0215-kth-largest-element-in-an-array
0240-search-a-2d-matrix-ii
0347-top-k-frequent-elements
0948-sort-an-array
1014-k-closest-points-to-origin

Heap (Priority Queue)

0023-merge-k-sorted-lists
0215-kth-largest-element-in-an-array
0239-sliding-window-maximum
0264-ugly-number-ii
0295-find-median-from-data-stream
0347-top-k-frequent-elements
0407-trapping-rain-water-ii
0621-task-scheduler
0632-smallest-range-covering-elements-from-k-lists
0789-kth-largest-element-in-a-stream
0892-shortest-subarray-with-sum-at-least-k
0948-sort-an-array
1014-k-closest-points-to-origin
1304-longest-happy-string
1325-path-with-maximum-probability
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1917-maximum-average-pass-ratio
2054-the-number-of-the-smallest-unoccupied-chair
2300-construct-string-with-repeat-limit
2375-minimum-obstacle-removal-to-reach-corner
2488-divide-intervals-into-minimum-number-of-groups
2616-maximal-score-after-applying-k-operations
2692-take-gifts-from-the-richest-pile
2695-find-score-of-an-array-after-marking-all-elements
2711-minimum-time-to-visit-a-cell-in-a-grid
2803-modify-graph-edge-weights
3181-find-building-where-alice-and-bob-can-meet
3555-final-array-state-after-k-multiplication-operations-i

Merge Sort

0023-merge-k-sorted-lists
0948-sort-an-array

Bucket Sort

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

Radix Sort

0948-sort-an-array

Counting Sort

0169-majority-element
0229-majority-element-ii
0274-h-index
0347-top-k-frequent-elements
0621-task-scheduler
0920-uncommon-words-from-two-sentences
0948-sort-an-array
1396-count-servers-that-communicate
1502-construct-k-palindrome-strings
1620-check-if-array-pairs-are-divisible-by-k
1786-count-the-number-of-consistent-strings
1901-equal-sum-arrays-with-minimum-number-of-operations
1915-check-if-one-string-swap-can-make-strings-equal
2163-kth-distinct-string-in-an-array
2300-construct-string-with-repeat-limit
2356-largest-combination-with-bitwise-and-greater-than-zero
2494-sum-of-prefix-scores-of-strings
3276-minimum-number-of-pushes-to-type-word-ii
3455-minimum-length-of-string-after-operations

Dynamic Programming

0005-longest-palindromic-substring
0010-regular-expression-matching
0053-maximum-subarray
0055-jump-game
0064-minimum-path-sum
0070-climbing-stairs
0118-pascals-triangle
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0139-word-break
0152-maximum-product-subarray
0198-house-robber
0241-different-ways-to-add-parentheses
0264-ugly-number-ii
0322-coin-change
0338-counting-bits
0494-target-sum
0650-2-keys-keyboard
0664-strange-printer
0678-valid-parenthesis-string
1025-minimum-cost-for-tickets
1196-filling-bookcase-shelves
1240-stone-game-ii
1250-longest-common-subsequence
1402-count-square-submatrices-with-all-ones
1456-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance
1511-count-number-of-teams
1700-minimum-time-to-make-rope-colorful
1756-minimum-deletions-to-make-string-balanced
1766-minimum-number-of-removals-to-make-mountain-array
2067-maximum-number-of-points-with-cost
2554-minimum-total-distance-traveled
2562-count-ways-to-build-good-strings
2755-extra-characters-in-a-string
2794-maximum-number-of-moves-in-a-grid

Shortest Path

1325-path-with-maximum-probability
1456-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
2171-second-minimum-time-to-reach-destination
2375-minimum-obstacle-removal-to-reach-corner
2711-minimum-time-to-visit-a-cell-in-a-grid
2803-modify-graph-edge-weights
3235-minimum-cost-to-convert-string-i

Binary Indexed Tree

1511-count-number-of-teams
3181-find-building-where-alice-and-bob-can-meet

Design

0146-lru-cache
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
0380-insert-delete-getrandom-o1
0432-all-oone-data-structure
0729-my-calendar-i
0731-my-calendar-ii
0789-kth-largest-element-in-a-stream
0816-design-hashset
0859-design-circular-deque
1023-time-based-key-value-store
1497-design-a-stack-with-increment-operation

Binary Search Tree

0099-recover-binary-search-tree
0108-convert-sorted-array-to-binary-search-tree
0173-binary-search-tree-iterator
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0789-kth-largest-element-in-a-stream

Data Stream

0295-find-median-from-data-stream
0789-kth-largest-element-in-a-stream

Backtracking

0017-letter-combinations-of-a-phone-number
0039-combination-sum
0040-combination-sum-ii
0212-word-search-ii
0494-target-sum
1715-split-a-string-into-the-max-number-of-unique-substrings
2170-count-number-of-maximum-bitwise-or-subsets

Prefix Sum

0209-minimum-size-subarray-sum
0731-my-calendar-ii
0892-shortest-subarray-with-sum-at-least-k
0912-random-pick-with-weight
1046-max-consecutive-ones-iii
1240-stone-game-ii
1435-xor-queries-of-a-subarray
1473-find-the-longest-substring-containing-vowels-in-even-counts
1537-maximum-score-after-splitting-a-string
1694-make-sum-divisible-by-p
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1940-maximum-xor-for-each-query
2006-find-the-student-that-will-replace-the-chalk
2059-unique-length-3-palindromic-subsequences
2145-grid-game
2358-number-of-ways-to-split-array
2465-shifting-letters-ii
2488-divide-intervals-into-minimum-number-of-groups
2691-count-vowel-strings-in-ranges
3427-special-array-ii

Game Theory

1240-stone-game-ii

Bit Manipulation

0190-reverse-bits
0191-number-of-1-bits
0338-counting-bits
0371-sum-of-two-integers
0476-number-complement
1435-xor-queries-of-a-subarray
1473-find-the-longest-substring-containing-vowels-in-even-counts
1487-cinema-seat-allocation
1786-count-the-number-of-consistent-strings
1940-maximum-xor-for-each-query
2059-unique-length-3-palindromic-subsequences
2170-count-number-of-maximum-bitwise-or-subsets
2323-minimum-bit-flips-to-convert-number
2356-largest-combination-with-bitwise-and-greater-than-zero
2503-longest-subarray-with-maximum-bitwise-and
2509-minimize-xor
2533-bitwise-xor-of-all-pairings
2766-find-the-prefix-common-array-of-two-arrays
2792-neighboring-bitwise-xor
3291-find-if-array-can-be-sorted

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0023-merge-k-sorted-lists
0083-remove-duplicates-from-sorted-list
0086-partition-list
0092-reverse-linked-list-ii
0141-linked-list-cycle
0143-reorder-list
0146-lru-cache
0160-intersection-of-two-linked-lists
0432-all-oone-data-structure
0725-split-linked-list-in-parts
0816-design-hashset
0859-design-circular-deque
0908-middle-of-the-linked-list
1484-linked-list-in-binary-tree
2411-spiral-matrix-iv
2903-insert-greatest-common-divisors-in-linked-list
3501-delete-nodes-from-linked-list-present-in-array

Number Theory

0204-count-primes
2716-prime-subtraction-operation
2903-insert-greatest-common-divisors-in-linked-list

Brainteaser

2503-longest-subarray-with-maximum-bitwise-and
2533-bitwise-xor-of-all-pairings

Memoization

0070-climbing-stairs
0139-word-break
0241-different-ways-to-add-parentheses

Rolling Hash

0214-shortest-palindrome
3309-count-prefix-and-suffix-pairs-i

String Matching

0214-shortest-palindrome
0572-subtree-of-another-tree
0812-rotate-string
1524-string-matching-in-an-array
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
3309-count-prefix-and-suffix-pairs-i

Hash Function

0214-shortest-palindrome
0572-subtree-of-another-tree
0816-design-hashset
3309-count-prefix-and-suffix-pairs-i

Trie

0014-longest-common-prefix
0139-word-break
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0212-word-search-ii
0386-lexicographical-numbers
0440-k-th-smallest-in-lexicographical-order
1350-remove-sub-folders-from-the-filesystem
2494-sum-of-prefix-scores-of-strings
2755-extra-characters-in-a-string
3309-count-prefix-and-suffix-pairs-i
3329-find-the-length-of-the-longest-common-prefix

Segment Tree

0729-my-calendar-i
0731-my-calendar-ii
3181-find-building-where-alice-and-bob-can-meet

Ordered Set

0729-my-calendar-i
0731-my-calendar-ii

Doubly-Linked List

0146-lru-cache
0432-all-oone-data-structure

Monotonic Stack

0084-largest-rectangle-in-histogram
0316-remove-duplicate-letters
0402-remove-k-digits
0780-max-chunks-to-make-sorted
1002-maximum-width-ramp
1570-final-prices-with-a-special-discount-in-a-shop
1679-shortest-subarray-to-be-removed-to-make-array-sorted
3181-find-building-where-alice-and-bob-can-meet

Enumeration

0204-count-primes
2170-count-number-of-maximum-bitwise-or-subsets

Randomized

0380-insert-delete-getrandom-o1
0912-random-pick-with-weight

Quickselect

0215-kth-largest-element-in-an-array
0347-top-k-frequent-elements
1014-k-closest-points-to-origin

Monotonic Queue

0239-sliding-window-maximum
0892-shortest-subarray-with-sum-at-least-k

Iterator

0173-binary-search-tree-iterator

Geometry

1014-k-closest-points-to-origin

Eulerian Circuit

2201-valid-arrangement-of-pairs