LeetCode

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

LeetCode Topics

Database

0197-rising-temperature
0570-managers-with-at-least-5-direct-reports
0577-employee-bonus
0584-find-customer-referee
0595-big-countries
0610-triangle-judgement
0620-not-boring-movies
1153-product-sales-analysis-i
1174-immediate-food-delivery-ii
1258-article-views-i
1415-students-and-examinations
1509-replace-employee-id-with-the-unique-identifier
1724-customer-who-visited-but-did-not-make-any-transactions
1773-percentage-of-users-attended-a-contest
1801-average-time-of-process-per-machine
1827-invalid-tweets
1908-recyclable-and-low-fat-products
3220-odd-and-even-transactions

Array

0001-two-sum
0004-median-of-two-sorted-arrays
0011-container-with-most-water
0015-3sum
0031-next-permutation
0037-sudoku-solver
0039-combination-sum
0046-permutations
0053-maximum-subarray
0055-jump-game
0056-merge-intervals
0063-unique-paths-ii
0064-minimum-path-sum
0066-plus-one
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0080-remove-duplicates-from-sorted-array-ii
0085-maximal-rectangle
0088-merge-sorted-array
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0118-pascals-triangle
0119-pascals-triangle-ii
0120-triangle
0121-best-time-to-buy-and-sell-stock
0130-surrounded-regions
0134-gas-station
0135-candy
0136-single-number
0137-single-number-ii
0139-word-break
0140-word-break-ii
0167-two-sum-ii-input-array-is-sorted
0174-dungeon-game
0179-largest-number
0189-rotate-array
0198-house-robber
0204-count-primes
0209-minimum-size-subarray-sum
0221-maximal-square
0238-product-of-array-except-self
0239-sliding-window-maximum
0240-search-a-2d-matrix-ii
0260-single-number-iii
0268-missing-number
0300-longest-increasing-subsequence
0315-count-of-smaller-numbers-after-self
0322-coin-change
0373-find-k-pairs-with-smallest-sums
0416-partition-equal-subset-sum
0421-maximum-xor-of-two-numbers-in-an-array
0475-heaters
0480-sliding-window-median
0494-target-sum
0518-coin-change-ii
0542-01-matrix
0560-subarray-sum-equals-k
0632-smallest-range-covering-elements-from-k-lists
0721-accounts-merge
0729-my-calendar-i
0731-my-calendar-ii
0733-flood-fill
0740-delete-and-earn
0840-magic-squares-in-grid
0859-design-circular-deque
0906-walking-robot-simulation
0967-minimum-falling-path-sum
0979-di-string-match
1002-maximum-width-ramp
1025-minimum-cost-for-tickets
1036-rotting-oranges
1046-max-consecutive-ones-iii
1073-number-of-enclaves
1240-stone-game-ii
1284-four-divisors
1293-three-consecutive-odds
1350-remove-sub-folders-from-the-filesystem
1352-maximum-profit-in-job-scheduling
1402-count-square-submatrices-with-all-ones
1435-xor-queries-of-a-subarray
1524-string-matching-in-an-array
1531-number-of-ways-to-wear-different-hats-to-each-other
1538-maximum-points-you-can-obtain-from-cards
1605-minimum-number-of-days-to-make-m-bouquets
1628-count-submatrices-with-all-ones
1631-number-of-sub-arrays-with-odd-sum
1631-path-with-minimum-effort
1669-minimum-cost-to-cut-a-stick
1697-checking-existence-of-edge-length-limited-paths
1786-count-the-number-of-consistent-strings
1826-maximum-xor-with-an-element-from-array
1833-find-the-highest-altitude
1834-minimum-number-of-people-to-teach
1876-map-of-highest-peak
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1917-maximum-average-pass-ratio
1983-maximum-population-year
1988-minimize-maximum-pair-sum-in-array
2006-find-the-student-that-will-replace-the-chalk
2048-build-array-from-permutation
2058-concatenation-of-array
2067-maximum-number-of-points-with-cost
2132-convert-1d-array-into-2d-array
2137-final-value-of-variable-after-performing-operations
2155-find-missing-observations
2160-minimum-operations-to-make-a-uni-value-grid
2169-simple-bank-system
2170-count-number-of-maximum-bitwise-or-subsets
2215-finding-3-digit-even-numbers
2229-maximum-fruits-harvested-after-at-most-k-steps
2232-adding-spaces-to-a-string
2308-divide-array-into-equal-pairs
2316-count-hills-and-valleys-in-an-array
2358-number-of-ways-to-split-array
2375-minimum-obstacle-removal-to-reach-corner
2387-partition-array-such-that-maximum-difference-is-k
2421-number-of-good-paths
2449-maximum-number-of-robots-within-budget
2488-divide-intervals-into-minimum-number-of-groups
2494-sum-of-prefix-scores-of-strings
2497-maximum-matching-of-players-with-trainers
2503-longest-subarray-with-maximum-bitwise-and
2529-range-product-queries-of-powers
2581-divide-players-into-teams-of-equal-skill
2614-maximum-count-of-positive-integer-and-negative-integer
2616-maximal-score-after-applying-k-operations
2618-maximize-the-minimum-powered-city
2685-first-completely-painted-row-or-column
2689-rearranging-fruits
2691-count-vowel-strings-in-ranges
2692-take-gifts-from-the-richest-pile
2753-minimum-number-of-operations-to-make-all-array-elements-equal-to-1
2856-count-complete-subarrays-in-an-array
3075-maximize-happiness-of-selected-children
3152-maximum-value-of-an-ordered-triplet-ii
3154-maximum-value-of-an-ordered-triplet-i
3181-find-building-where-alice-and-bob-can-meet
3194-find-words-containing-character
3227-find-missing-and-repeated-values
3270-minimum-moves-to-capture-the-queen
3291-find-if-array-can-be-sorted
3309-count-prefix-and-suffix-pairs-i
3329-find-the-length-of-the-longest-common-prefix
3383-taking-maximum-energy-from-the-mystic-dungeon
3427-special-array-ii
3453-separate-squares-i
3501-delete-nodes-from-linked-list-present-in-array
3555-final-array-state-after-k-multiplication-operations-i
3619-adjacent-increasing-subarrays-detection-ii
3620-maximum-number-of-distinct-elements-after-operations
3621-minimum-operations-to-make-array-values-equal-to-k
3622-maximum-frequency-of-an-element-after-performing-operations-i
3744-minimum-operations-to-make-array-elements-zero
3789-maximize-subarrays-after-removing-one-conflicting-pair

Dynamic Programming

0005-longest-palindromic-substring
0053-maximum-subarray
0055-jump-game
0062-unique-paths
0063-unique-paths-ii
0064-minimum-path-sum
0072-edit-distance
0085-maximal-rectangle
0118-pascals-triangle
0119-pascals-triangle-ii
0120-triangle
0121-best-time-to-buy-and-sell-stock
0124-binary-tree-maximum-path-sum
0139-word-break
0140-word-break-ii
0174-dungeon-game
0198-house-robber
0221-maximal-square
0264-ugly-number-ii
0300-longest-increasing-subsequence
0322-coin-change
0337-house-robber-iii
0416-partition-equal-subset-sum
0494-target-sum
0516-longest-palindromic-subsequence
0518-coin-change-ii
0542-01-matrix
0740-delete-and-earn
0803-cheapest-flights-within-k-stops
0923-super-egg-drop
0967-minimum-falling-path-sum
1013-fibonacci-number
1025-minimum-cost-for-tickets
1240-stone-game-ii
1250-longest-common-subsequence
1332-count-vowels-permutation
1352-maximum-profit-in-job-scheduling
1402-count-square-submatrices-with-all-ones
1531-number-of-ways-to-wear-different-hats-to-each-other
1628-count-submatrices-with-all-ones
1631-number-of-sub-arrays-with-odd-sum
1669-minimum-cost-to-cut-a-stick
2031-egg-drop-with-2-eggs-and-n-floors
2067-maximum-number-of-points-with-cost
2147-number-of-ways-to-divide-a-long-corridor
2395-longest-binary-subsequence-less-than-or-equal-to-k
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-ii

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0013-roman-to-integer
0037-sudoku-solver
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
0139-word-break
0140-word-break-ii
0208-implement-trie-prefix-tree
0264-ugly-number-ii
0268-missing-number
0421-maximum-xor-of-two-numbers-in-an-array
0424-longest-repeating-character-replacement
0432-all-oone-data-structure
0480-sliding-window-median
0560-subarray-sum-equals-k
0567-permutation-in-string
0632-smallest-range-covering-elements-from-k-lists
0721-accounts-merge
0740-delete-and-earn
0768-partition-labels
0840-magic-squares-in-grid
0865-smallest-subtree-with-all-the-deepest-nodes
0893-all-nodes-distance-k-in-binary-tree
0906-walking-robot-simulation
0920-uncommon-words-from-two-sentences
1123-lowest-common-ancestor-of-deepest-leaves
1460-number-of-substrings-containing-all-three-characters
1715-split-a-string-into-the-max-number-of-unique-substrings
1786-count-the-number-of-consistent-strings
1834-minimum-number-of-people-to-teach
2169-simple-bank-system
2215-finding-3-digit-even-numbers
2300-construct-string-with-repeat-limit
2308-divide-array-into-equal-pairs
2421-number-of-good-paths
2475-largest-palindromic-number
2581-divide-players-into-teams-of-equal-skill
2685-first-completely-painted-row-or-column
2689-rearranging-fruits
2856-count-complete-subarrays-in-an-array
3227-find-missing-and-repeated-values
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
3621-minimum-operations-to-make-array-values-equal-to-k
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-ii

Math

0002-add-two-numbers
0007-reverse-integer
0013-roman-to-integer
0062-unique-paths
0066-plus-one
0069-sqrtx
0189-rotate-array
0204-count-primes
0231-power-of-two
0264-ugly-number-ii
0268-missing-number
0441-arranging-coins
0564-find-the-closest-palindrome
0592-fraction-addition-and-subtraction
0670-maximum-swap
0840-magic-squares-in-grid
0910-nth-magical-number
0923-super-egg-drop
1013-fibonacci-number
1240-stone-game-ii
1284-four-divisors
1448-maximum-69-number
1631-number-of-sub-arrays-with-odd-sum
1800-concatenation-of-consecutive-binary-numbers
2031-egg-drop-with-2-eggs-and-n-floors
2147-number-of-ways-to-divide-a-long-corridor
2155-find-missing-observations
2160-minimum-operations-to-make-a-uni-value-grid
2704-maximum-difference-by-remapping-a-digit
2753-minimum-number-of-operations-to-make-all-array-elements-equal-to-1
2903-insert-greatest-common-divisors-in-linked-list
2998-count-symmetric-integers
3172-divisible-and-non-divisible-sums-difference
3227-find-missing-and-repeated-values
3555-final-array-state-after-k-multiplication-operations-i
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-ii
3744-minimum-operations-to-make-array-elements-zero

Heap (Priority Queue)

0239-sliding-window-maximum
0264-ugly-number-ii
0373-find-k-pairs-with-smallest-sums
0480-sliding-window-median
0632-smallest-range-covering-elements-from-k-lists
0803-cheapest-flights-within-k-stops
1304-longest-happy-string
1631-path-with-minimum-effort
1917-maximum-average-pass-ratio
2300-construct-string-with-repeat-limit
2375-minimum-obstacle-removal-to-reach-corner
2449-maximum-number-of-robots-within-budget
2488-divide-intervals-into-minimum-number-of-groups
2616-maximal-score-after-applying-k-operations
2692-take-gifts-from-the-richest-pile
3181-find-building-where-alice-and-bob-can-meet
3555-final-array-state-after-k-multiplication-operations-i

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0231-power-of-two
0234-palindrome-linked-list
1013-fibonacci-number
1197-parsing-a-boolean-expression
1667-find-kth-bit-in-nth-binary-string

Memoization

0139-word-break
0140-word-break-ii
1013-fibonacci-number
2395-longest-binary-subsequence-less-than-or-equal-to-k

Matrix

0037-sudoku-solver
0063-unique-paths-ii
0064-minimum-path-sum
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0085-maximal-rectangle
0130-surrounded-regions
0174-dungeon-game
0221-maximal-square
0240-search-a-2d-matrix-ii
0542-01-matrix
0733-flood-fill
0840-magic-squares-in-grid
0967-minimum-falling-path-sum
1036-rotting-oranges
1073-number-of-enclaves
1402-count-square-submatrices-with-all-ones
1628-count-submatrices-with-all-ones
1631-path-with-minimum-effort
1876-map-of-highest-peak
2132-convert-1d-array-into-2d-array
2160-minimum-operations-to-make-a-uni-value-grid
2375-minimum-obstacle-removal-to-reach-corner
2685-first-completely-painted-row-or-column
3227-find-missing-and-repeated-values

Breadth-First Search

0104-maximum-depth-of-binary-tree
0130-surrounded-regions
0210-course-schedule-ii
0322-coin-change
0515-find-largest-value-in-each-tree-row
0542-01-matrix
0547-number-of-provinces
0721-accounts-merge
0733-flood-fill
0801-is-graph-bipartite
0803-cheapest-flights-within-k-stops
0865-smallest-subtree-with-all-the-deepest-nodes
0893-all-nodes-distance-k-in-binary-tree
0922-possible-bipartition
1036-rotting-oranges
1073-number-of-enclaves
1123-lowest-common-ancestor-of-deepest-leaves
1448-count-good-nodes-in-binary-tree
1631-path-with-minimum-effort
1876-map-of-highest-peak
2316-count-unreachable-pairs-of-nodes-in-an-undirected-graph
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
2646-kth-largest-sum-in-a-binary-tree

Prefix Sum

0209-minimum-size-subarray-sum
0238-product-of-array-except-self
0560-subarray-sum-equals-k
0731-my-calendar-ii
1046-max-consecutive-ones-iii
1240-stone-game-ii
1435-xor-queries-of-a-subarray
1537-maximum-score-after-splitting-a-string
1538-maximum-points-you-can-obtain-from-cards
1631-number-of-sub-arrays-with-odd-sum
1833-find-the-highest-altitude
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1983-maximum-population-year
2006-find-the-student-that-will-replace-the-chalk
2229-maximum-fruits-harvested-after-at-most-k-steps
2358-number-of-ways-to-split-array
2449-maximum-number-of-robots-within-budget
2488-divide-intervals-into-minimum-number-of-groups
2529-range-product-queries-of-powers
2618-maximize-the-minimum-powered-city
2691-count-vowel-strings-in-ranges
3383-taking-maximum-energy-from-the-mystic-dungeon
3427-special-array-ii
3622-maximum-frequency-of-an-element-after-performing-operations-i
3789-maximize-subarrays-after-removing-one-conflicting-pair

Game Theory

1240-stone-game-ii

Bit Manipulation

0136-single-number
0137-single-number-ii
0231-power-of-two
0260-single-number-iii
0268-missing-number
0421-maximum-xor-of-two-numbers-in-an-array
0461-hamming-distance
0476-number-complement
1435-xor-queries-of-a-subarray
1531-number-of-ways-to-wear-different-hats-to-each-other
1786-count-the-number-of-consistent-strings
1800-concatenation-of-consecutive-binary-numbers
1826-maximum-xor-with-an-element-from-array
2170-count-number-of-maximum-bitwise-or-subsets
2308-divide-array-into-equal-pairs
2323-minimum-bit-flips-to-convert-number
2503-longest-subarray-with-maximum-bitwise-and
2529-range-product-queries-of-powers
3291-find-if-array-can-be-sorted
3744-minimum-operations-to-make-array-elements-zero

Bitmask

1531-number-of-ways-to-wear-different-hats-to-each-other

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0006-zigzag-conversion
0013-roman-to-integer
0014-longest-common-prefix
0020-valid-parentheses
0071-simplify-path
0072-edit-distance
0076-minimum-window-substring
0139-word-break
0140-word-break-ii
0179-largest-number
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0214-shortest-palindrome
0424-longest-repeating-character-replacement
0516-longest-palindromic-subsequence
0564-find-the-closest-palindrome
0567-permutation-in-string
0592-fraction-addition-and-subtraction
0721-accounts-merge
0768-partition-labels
0812-rotate-string
0920-uncommon-words-from-two-sentences
0957-minimum-add-to-make-parentheses-valid
0979-di-string-match
1122-longest-duplicate-substring
1197-parsing-a-boolean-expression
1250-longest-common-subsequence
1302-delete-characters-to-make-fancy-string
1304-longest-happy-string
1350-remove-sub-folders-from-the-filesystem
1460-number-of-substrings-containing-all-three-characters
1524-string-matching-in-an-array
1537-maximum-score-after-splitting-a-string
1667-find-kth-bit-in-nth-binary-string
1715-split-a-string-into-the-max-number-of-unique-substrings
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
2076-sum-of-digits-of-string-after-convert
2137-final-value-of-variable-after-performing-operations
2147-number-of-ways-to-divide-a-long-corridor
2232-adding-spaces-to-a-string
2300-construct-string-with-repeat-limit
2337-remove-digit-from-number-to-maximize-result
2395-longest-binary-subsequence-less-than-or-equal-to-k
2475-largest-palindromic-number
2494-sum-of-prefix-scores-of-strings
2580-circular-sentence
2691-count-vowel-strings-in-ranges
3194-find-words-containing-character
3195-separate-black-and-white-balls
3309-count-prefix-and-suffix-pairs-i
3329-find-the-length-of-the-longest-common-prefix
3447-clear-digits
3455-minimum-length-of-string-after-operations
3617-find-the-original-typed-string-i
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-ii
3798-largest-even-number

Simulation

0592-fraction-addition-and-subtraction
0906-walking-robot-simulation
1667-find-kth-bit-in-nth-binary-string
1800-concatenation-of-consecutive-binary-numbers
2006-find-the-student-that-will-replace-the-chalk
2048-build-array-from-permutation
2058-concatenation-of-array
2076-sum-of-digits-of-string-after-convert
2132-convert-1d-array-into-2d-array
2137-final-value-of-variable-after-performing-operations
2155-find-missing-observations
2169-simple-bank-system
2232-adding-spaces-to-a-string
2692-take-gifts-from-the-richest-pile
3447-clear-digits
3555-final-array-state-after-k-multiplication-operations-i

Two Pointers

0005-longest-palindromic-substring
0011-container-with-most-water
0015-3sum
0019-remove-nth-node-from-end-of-list
0031-next-permutation
0080-remove-duplicates-from-sorted-array-ii
0088-merge-sorted-array
0167-two-sum-ii-input-array-is-sorted
0189-rotate-array
0234-palindrome-linked-list
0475-heaters
0567-permutation-in-string
0768-partition-labels
0979-di-string-match
1697-checking-existence-of-edge-length-limited-paths
1988-minimize-maximum-pair-sum-in-array
2232-adding-spaces-to-a-string
2488-divide-intervals-into-minimum-number-of-groups
2497-maximum-matching-of-players-with-trainers
2581-divide-players-into-teams-of-equal-skill
3195-separate-black-and-white-balls

Greedy

0011-container-with-most-water
0055-jump-game
0134-gas-station
0135-candy
0179-largest-number
0632-smallest-range-covering-elements-from-k-lists
0670-maximum-swap
0768-partition-labels
0957-minimum-add-to-make-parentheses-valid
0979-di-string-match
1304-longest-happy-string
1448-maximum-69-number
1818-maximum-score-from-removing-substrings
1834-minimum-number-of-people-to-teach
1917-maximum-average-pass-ratio
1988-minimize-maximum-pair-sum-in-array
2300-construct-string-with-repeat-limit
2337-remove-digit-from-number-to-maximize-result
2387-partition-array-such-that-maximum-difference-is-k
2395-longest-binary-subsequence-less-than-or-equal-to-k
2475-largest-palindromic-number
2488-divide-intervals-into-minimum-number-of-groups
2497-maximum-matching-of-players-with-trainers
2616-maximal-score-after-applying-k-operations
2618-maximize-the-minimum-powered-city
2689-rearranging-fruits
2704-maximum-difference-by-remapping-a-digit
3075-maximize-happiness-of-selected-children
3195-separate-black-and-white-balls
3620-maximum-number-of-distinct-elements-after-operations

Enumeration

0204-count-primes
2170-count-number-of-maximum-bitwise-or-subsets
2215-finding-3-digit-even-numbers
2337-remove-digit-from-number-to-maximize-result
2998-count-symmetric-integers
3270-minimum-moves-to-capture-the-queen
3789-maximize-subarrays-after-removing-one-conflicting-pair

Number Theory

0204-count-primes
2753-minimum-number-of-operations-to-make-all-array-elements-equal-to-1
2903-insert-greatest-common-divisors-in-linked-list

Binary Search

0004-median-of-two-sorted-arrays
0069-sqrtx
0074-search-a-2d-matrix
0167-two-sum-ii-input-array-is-sorted
0209-minimum-size-subarray-sum
0240-search-a-2d-matrix-ii
0268-missing-number
0300-longest-increasing-subsequence
0315-count-of-smaller-numbers-after-self
0374-guess-number-higher-or-lower
0441-arranging-coins
0475-heaters
0729-my-calendar-i
0731-my-calendar-ii
0910-nth-magical-number
0923-super-egg-drop
1046-max-consecutive-ones-iii
1122-longest-duplicate-substring
1352-maximum-profit-in-job-scheduling
1605-minimum-number-of-days-to-make-m-bouquets
1631-path-with-minimum-effort
2006-find-the-student-that-will-replace-the-chalk
2229-maximum-fruits-harvested-after-at-most-k-steps
2449-maximum-number-of-robots-within-budget
2614-maximum-count-of-positive-integer-and-negative-integer
2618-maximize-the-minimum-powered-city
3181-find-building-where-alice-and-bob-can-meet
3427-special-array-ii
3453-separate-squares-i
3619-adjacent-increasing-subarrays-detection-ii
3622-maximum-frequency-of-an-element-after-performing-operations-i

Stack

0020-valid-parentheses
0071-simplify-path
0085-maximal-rectangle
0234-palindrome-linked-list
0776-n-ary-tree-postorder-traversal
0957-minimum-add-to-make-parentheses-valid
1002-maximum-width-ramp
1197-parsing-a-boolean-expression
1628-count-submatrices-with-all-ones
1818-maximum-score-from-removing-substrings
3181-find-building-where-alice-and-bob-can-meet
3447-clear-digits

Tree

0104-maximum-depth-of-binary-tree
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0124-binary-tree-maximum-path-sum
0230-kth-smallest-element-in-a-bst
0337-house-robber-iii
0515-find-largest-value-in-each-tree-row
0572-subtree-of-another-tree
0776-n-ary-tree-postorder-traversal
0865-smallest-subtree-with-all-the-deepest-nodes
0893-all-nodes-distance-k-in-binary-tree
1123-lowest-common-ancestor-of-deepest-leaves
1448-count-good-nodes-in-binary-tree
2421-number-of-good-paths
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

Depth-First Search

0104-maximum-depth-of-binary-tree
0124-binary-tree-maximum-path-sum
0130-surrounded-regions
0210-course-schedule-ii
0211-design-add-and-search-words-data-structure
0230-kth-smallest-element-in-a-bst
0337-house-robber-iii
0386-lexicographical-numbers
0515-find-largest-value-in-each-tree-row
0547-number-of-provinces
0572-subtree-of-another-tree
0721-accounts-merge
0733-flood-fill
0776-n-ary-tree-postorder-traversal
0801-is-graph-bipartite
0803-cheapest-flights-within-k-stops
0865-smallest-subtree-with-all-the-deepest-nodes
0893-all-nodes-distance-k-in-binary-tree
0922-possible-bipartition
1073-number-of-enclaves
1123-lowest-common-ancestor-of-deepest-leaves
1350-remove-sub-folders-from-the-filesystem
1448-count-good-nodes-in-binary-tree
1631-path-with-minimum-effort
2316-count-unreachable-pairs-of-nodes-in-an-undirected-graph
2493-reverse-odd-levels-of-binary-tree

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0234-palindrome-linked-list
0432-all-oone-data-structure
0859-design-circular-deque
2903-insert-greatest-common-divisors-in-linked-list
3501-delete-nodes-from-linked-list-present-in-array

Divide and Conquer

0004-median-of-two-sorted-arrays
0053-maximum-subarray
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0240-search-a-2d-matrix-ii
0315-count-of-smaller-numbers-after-self

Binary Indexed Tree

0315-count-of-smaller-numbers-after-self
3181-find-building-where-alice-and-bob-can-meet

Segment Tree

0315-count-of-smaller-numbers-after-self
0729-my-calendar-i
0731-my-calendar-ii
3181-find-building-where-alice-and-bob-can-meet
3789-maximize-subarrays-after-removing-one-conflicting-pair

Merge Sort

0315-count-of-smaller-numbers-after-self

Ordered Set

0315-count-of-smaller-numbers-after-self
0729-my-calendar-i
0731-my-calendar-ii

Counting

0920-uncommon-words-from-two-sentences
1786-count-the-number-of-consistent-strings
1983-maximum-population-year
2300-construct-string-with-repeat-limit
2308-divide-array-into-equal-pairs
2475-largest-palindromic-number
2494-sum-of-prefix-scores-of-strings
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

Brainteaser

2503-longest-subarray-with-maximum-bitwise-and

Sorting

0015-3sum
0056-merge-intervals
0088-merge-sorted-array
0179-largest-number
0268-missing-number
0475-heaters
0632-smallest-range-covering-elements-from-k-lists
0721-accounts-merge
1352-maximum-profit-in-job-scheduling
1669-minimum-cost-to-cut-a-stick
1697-checking-existence-of-edge-length-limited-paths
1988-minimize-maximum-pair-sum-in-array
2160-minimum-operations-to-make-a-uni-value-grid
2215-finding-3-digit-even-numbers
2387-partition-array-such-that-maximum-difference-is-k
2421-number-of-good-paths
2488-divide-intervals-into-minimum-number-of-groups
2497-maximum-matching-of-players-with-trainers
2581-divide-players-into-teams-of-equal-skill
2646-kth-largest-sum-in-a-binary-tree
2689-rearranging-fruits
3075-maximize-happiness-of-selected-children
3291-find-if-array-can-be-sorted
3620-maximum-number-of-distinct-elements-after-operations
3622-maximum-frequency-of-an-element-after-performing-operations-i

Rolling Hash

0214-shortest-palindrome
1122-longest-duplicate-substring
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
3309-count-prefix-and-suffix-pairs-i

Hash Function

0214-shortest-palindrome
0572-subtree-of-another-tree
1122-longest-duplicate-substring
3309-count-prefix-and-suffix-pairs-i

Trie

0014-longest-common-prefix
0139-word-break
0140-word-break-ii
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0386-lexicographical-numbers
0421-maximum-xor-of-two-numbers-in-an-array
1350-remove-sub-folders-from-the-filesystem
1826-maximum-xor-with-an-element-from-array
2494-sum-of-prefix-scores-of-strings
3309-count-prefix-and-suffix-pairs-i
3329-find-the-length-of-the-longest-common-prefix

Design

0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0432-all-oone-data-structure
0729-my-calendar-i
0731-my-calendar-ii
0859-design-circular-deque
2169-simple-bank-system

Queue

0239-sliding-window-maximum
0859-design-circular-deque
2449-maximum-number-of-robots-within-budget
2618-maximize-the-minimum-powered-city

Doubly-Linked List

0432-all-oone-data-structure

Binary Tree

0104-maximum-depth-of-binary-tree
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0124-binary-tree-maximum-path-sum
0230-kth-smallest-element-in-a-bst
0337-house-robber-iii
0515-find-largest-value-in-each-tree-row
0572-subtree-of-another-tree
0865-smallest-subtree-with-all-the-deepest-nodes
0893-all-nodes-distance-k-in-binary-tree
1123-lowest-common-ancestor-of-deepest-leaves
1448-count-good-nodes-in-binary-tree
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

Backtracking

0037-sudoku-solver
0039-combination-sum
0046-permutations
0077-combinations
0140-word-break-ii
0494-target-sum
1715-split-a-string-into-the-max-number-of-unique-substrings
2170-count-number-of-maximum-bitwise-or-subsets

Sliding Window

0003-longest-substring-without-repeating-characters
0076-minimum-window-substring
0209-minimum-size-subarray-sum
0239-sliding-window-maximum
0424-longest-repeating-character-replacement
0480-sliding-window-median
0567-permutation-in-string
0632-smallest-range-covering-elements-from-k-lists
1046-max-consecutive-ones-iii
1122-longest-duplicate-substring
1460-number-of-substrings-containing-all-three-characters
1538-maximum-points-you-can-obtain-from-cards
2229-maximum-fruits-harvested-after-at-most-k-steps
2449-maximum-number-of-robots-within-budget
2618-maximize-the-minimum-powered-city
2856-count-complete-subarrays-in-an-array
3622-maximum-frequency-of-an-element-after-performing-operations-i

Monotonic Stack

0085-maximal-rectangle
1002-maximum-width-ramp
1628-count-submatrices-with-all-ones
3181-find-building-where-alice-and-bob-can-meet

Union Find

0130-surrounded-regions
0547-number-of-provinces
0721-accounts-merge
0801-is-graph-bipartite
0922-possible-bipartition
1073-number-of-enclaves
1631-path-with-minimum-effort
1697-checking-existence-of-edge-length-limited-paths
2316-count-unreachable-pairs-of-nodes-in-an-undirected-graph
2421-number-of-good-paths

Graph

0210-course-schedule-ii
0547-number-of-provinces
0801-is-graph-bipartite
0803-cheapest-flights-within-k-stops
0922-possible-bipartition
1697-checking-existence-of-edge-length-limited-paths
2316-count-unreachable-pairs-of-nodes-in-an-undirected-graph
2375-minimum-obstacle-removal-to-reach-corner
2421-number-of-good-paths

Binary Search Tree

0230-kth-smallest-element-in-a-bst

Shortest Path

0803-cheapest-flights-within-k-stops
2375-minimum-obstacle-removal-to-reach-corner

Interactive

0374-guess-number-higher-or-lower

Combinatorics

0062-unique-paths

Monotonic Queue

0239-sliding-window-maximum
2449-maximum-number-of-robots-within-budget

Suffix Array

1122-longest-duplicate-substring

Topological Sort

0210-course-schedule-ii