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

LeetCode Topics

Array

0001-two-sum
0004-median-of-two-sorted-arrays
0011-container-with-most-water
0015-3sum
0016-3sum-closest
0018-4sum
0026-remove-duplicates-from-sorted-array
0027-remove-element
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0036-valid-sudoku
0037-sudoku-solver
0039-combination-sum
0040-combination-sum-ii
0041-first-missing-positive
0042-trapping-rain-water
0046-permutations
0047-permutations-ii
0048-rotate-image
0049-group-anagrams
0051-n-queens
0053-maximum-subarray
0054-spiral-matrix
0055-jump-game
0056-merge-intervals
0059-spiral-matrix-ii
0063-unique-paths-ii
0064-minimum-path-sum
0066-plus-one
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0075-sort-colors
0078-subsets
0079-word-search
0080-remove-duplicates-from-sorted-array-ii
0081-search-in-rotated-sorted-array-ii
0084-largest-rectangle-in-histogram
0085-maximal-rectangle
0088-merge-sorted-array
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
0119-pascals-triangle-ii
0120-triangle
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0123-best-time-to-buy-and-sell-stock-iii
0128-longest-consecutive-sequence
0130-surrounded-regions
0134-gas-station
0135-candy
0136-single-number
0137-single-number-ii
0150-evaluate-reverse-polish-notation
0152-maximum-product-subarray
0153-find-minimum-in-rotated-sorted-array
0154-find-minimum-in-rotated-sorted-array-ii
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0169-majority-element
0188-best-time-to-buy-and-sell-stock-iv
0189-rotate-array
0198-house-robber
0200-number-of-islands
0204-count-primes
0209-minimum-size-subarray-sum
0213-house-robber-ii
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0219-contains-duplicate-ii
0228-summary-ranges
0229-majority-element-ii
0238-product-of-array-except-self
0239-sliding-window-maximum
0240-search-a-2d-matrix-ii
0260-single-number-iii
0268-missing-number
0274-h-index
0283-move-zeroes
0287-find-the-duplicate-number
0289-game-of-life
0300-longest-increasing-subsequence
0303-range-sum-query-immutable
0307-range-sum-query-mutable
0322-coin-change
0347-top-k-frequent-elements
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0354-russian-doll-envelopes
0413-arithmetic-slices
0416-partition-equal-subset-sum
0417-pacific-atlantic-water-flow
0435-non-overlapping-intervals
0442-find-all-duplicates-in-an-array
0446-arithmetic-slices-ii-subsequence
0448-find-all-numbers-disappeared-in-an-array
0452-minimum-number-of-arrows-to-burst-balloons
0453-minimum-moves-to-equal-array-elements
0455-assign-cookies
0463-island-perimeter
0493-reverse-pairs
0496-next-greater-element-i
0502-ipo
0503-next-greater-element-ii
0506-relative-ranks
0532-k-diff-pairs-in-an-array
0540-single-element-in-a-sorted-array
0542-01-matrix
0560-subarray-sum-equals-k
0628-maximum-product-of-three-numbers
0632-smallest-range-covering-elements-from-k-lists
0645-set-mismatch
0682-baseball-game
0692-top-k-frequent-words
0695-max-area-of-island
0724-find-pivot-index
0733-flood-fill
0735-asteroid-collision
0739-daily-temperatures
0741-cherry-pickup
0747-min-cost-climbing-stairs
0777-toeplitz-matrix
0792-binary-search
0797-rabbits-in-forest
0802-k-th-smallest-prime-fraction
0817-design-hashmap
0860-design-circular-queue
0861-flipping-an-image
0875-longest-mountain-in-array
0882-peak-index-in-a-mountain-array
0890-lemonade-change
0891-score-after-flipping-matrix
0898-transpose-matrix
0907-koko-eating-bananas
0917-boats-to-save-people
0940-fruit-into-baskets
0948-sort-an-array
0966-binary-subarrays-with-sum
0987-reveal-cards-in-increasing-order
1014-k-closest-points-to-origin
1019-squares-of-a-sorted-array
1034-subarrays-with-k-different-integers
1036-rotting-oranges
1046-max-consecutive-ones-iii
1047-maximize-sum-of-array-after-k-negations
1050-construct-binary-search-tree-from-preorder-traversal
1056-capacity-to-ship-packages-within-d-days
1072-next-greater-node-in-linked-list
1073-number-of-enclaves
1104-coloring-a-border
1127-last-stone-weight
1206-corporate-flight-bookings
1217-relative-sort-array
1293-three-consecutive-odds
1319-unique-number-of-occurrences
1349-check-if-it-is-a-straight-line
1367-maximum-height-by-stacking-cuboids
1370-count-number-of-nice-subarrays
1426-find-n-unique-integers-sum-up-to-zero
1435-xor-queries-of-a-subarray
1451-minimum-number-of-taps-to-open-to-water-a-garden
1479-construct-target-array-with-multiple-sums
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1489-pizza-with-3n-slices
1503-reducing-dishes
1514-minimum-value-to-get-positive-step-by-step-sum
1538-maximum-points-you-can-obtain-from-cards
1603-running-sum-of-1d-array
1620-check-if-array-pairs-are-divisible-by-k
1646-kth-missing-positive-number
1651-shuffle-string
1656-count-good-triplets
1706-min-cost-to-connect-all-points
1711-find-valid-matrix-given-row-and-column-sums
1730-special-array-with-x-elements-greater-than-or-equal-x
1753-path-with-minimum-effort
1794-minimize-deviation-in-array
1798-max-number-of-k-sum-pairs
1829-maximum-units-on-a-truck
1833-find-the-highest-altitude
1878-check-if-array-is-sorted-and-rotated
1925-count-nice-pairs-in-an-array
1940-maximum-xor-for-each-query
1951-find-the-winner-of-the-circular-game
1995-finding-pairs-with-a-certain-sum
2016-reduction-operations-to-make-the-array-elements-equal

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0012-integer-to-roman
0013-roman-to-integer
0017-letter-combinations-of-a-phone-number
0036-valid-sudoku
0037-sudoku-solver
0041-first-missing-positive
0049-group-anagrams
0073-set-matrix-zeroes
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0127-word-ladder
0128-longest-consecutive-sequence
0133-clone-graph
0138-copy-list-with-random-pointer
0141-linked-list-cycle
0142-linked-list-cycle-ii
0160-intersection-of-two-linked-lists
0169-majority-element
0202-happy-number
0205-isomorphic-strings
0208-implement-trie-prefix-tree
0217-contains-duplicate
0219-contains-duplicate-ii
0229-majority-element-ii
0242-valid-anagram
0268-missing-number
0290-word-pattern
0347-top-k-frequent-elements
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0389-find-the-difference
0424-longest-repeating-character-replacement
0438-find-all-anagrams-in-a-string
0442-find-all-duplicates-in-an-array
0448-find-all-numbers-disappeared-in-an-array
0451-sort-characters-by-frequency
0496-next-greater-element-i
0532-k-diff-pairs-in-an-array
0560-subarray-sum-equals-k
0567-permutation-in-string
0632-smallest-range-covering-elements-from-k-lists
0645-set-mismatch
0692-top-k-frequent-words
0778-reorganize-string
0797-rabbits-in-forest
0817-design-hashmap
0893-all-nodes-distance-k-in-binary-tree
0940-fruit-into-baskets
0966-binary-subarrays-with-sum
1034-subarrays-with-k-different-integers
1160-letter-tile-possibilities
1217-relative-sort-array
1267-remove-zero-sum-consecutive-nodes-from-linked-list
1319-unique-number-of-occurrences
1370-count-number-of-nice-subarrays
1460-number-of-substrings-containing-all-three-characters
1620-check-if-array-pairs-are-divisible-by-k
1777-determine-if-two-strings-are-close
1798-max-number-of-k-sum-pairs
1925-count-nice-pairs-in-an-array
1995-finding-pairs-with-a-certain-sum

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0023-merge-k-sorted-lists
0024-swap-nodes-in-pairs
0025-reverse-nodes-in-k-group
0061-rotate-list
0082-remove-duplicates-from-sorted-list-ii
0083-remove-duplicates-from-sorted-list
0086-partition-list
0092-reverse-linked-list-ii
0109-convert-sorted-list-to-binary-search-tree
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
0138-copy-list-with-random-pointer
0141-linked-list-cycle
0142-linked-list-cycle-ii
0143-reorder-list
0147-insertion-sort-list
0148-sort-list
0160-intersection-of-two-linked-lists
0203-remove-linked-list-elements
0206-reverse-linked-list
0234-palindrome-linked-list
0237-delete-node-in-a-linked-list
0328-odd-even-linked-list
0445-add-two-numbers-ii
0528-swapping-nodes-in-a-linked-list
0725-split-linked-list-in-parts
0766-flatten-a-multilevel-doubly-linked-list
0817-design-hashmap
0860-design-circular-queue
0908-middle-of-the-linked-list
1072-next-greater-node-in-linked-list
1267-remove-zero-sum-consecutive-nodes-from-linked-list
1411-convert-binary-number-in-a-linked-list-to-integer
1484-linked-list-in-binary-tree
1765-merge-in-between-linked-lists

Math

0002-add-two-numbers
0007-reverse-integer
0009-palindrome-number
0012-integer-to-roman
0013-roman-to-integer
0043-multiply-strings
0048-rotate-image
0050-powx-n
0060-permutation-sequence
0062-unique-paths
0066-plus-one
0067-add-binary
0069-sqrtx
0070-climbing-stairs
0096-unique-binary-search-trees
0150-evaluate-reverse-polish-notation
0168-excel-sheet-column-title
0171-excel-sheet-column-number
0189-rotate-array
0202-happy-number
0204-count-primes
0231-power-of-two
0258-add-digits
0263-ugly-number
0268-missing-number
0326-power-of-three
0342-power-of-four
0367-valid-perfect-square
0371-sum-of-two-integers
0375-guess-number-higher-or-lower-ii
0415-add-strings
0441-arranging-coins
0445-add-two-numbers-ii
0453-minimum-moves-to-equal-array-elements
0507-perfect-number
0628-maximum-product-of-three-numbers
0633-sum-of-square-numbers
0795-k-th-symbol-in-grammar
0797-rabbits-in-forest
1013-fibonacci-number
1014-k-closest-points-to-origin
1236-n-th-tribonacci-number
1349-check-if-it-is-a-straight-line
1370-count-number-of-nice-subarrays
1411-convert-binary-number-in-a-linked-list-to-integer
1426-find-n-unique-integers-sum-up-to-zero
1448-maximum-69-number
1610-xor-operation-in-an-array
1642-water-bottles
1925-count-nice-pairs-in-an-array
1951-find-the-winner-of-the-circular-game

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0024-swap-nodes-in-pairs
0025-reverse-nodes-in-k-group
0044-wildcard-matching
0050-powx-n
0060-permutation-sequence
0143-reorder-list
0203-remove-linked-list-elements
0206-reverse-linked-list
0231-power-of-two
0234-palindrome-linked-list
0326-power-of-three
0342-power-of-four
0795-k-th-symbol-in-grammar
1013-fibonacci-number
1951-find-the-winner-of-the-circular-game

String

0003-longest-substring-without-repeating-characters
0006-zigzag-conversion
0012-integer-to-roman
0013-roman-to-integer
0014-longest-common-prefix
0017-letter-combinations-of-a-phone-number
0020-valid-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string
0038-count-and-say
0043-multiply-strings
0044-wildcard-matching
0049-group-anagrams
0058-length-of-last-word
0067-add-binary
0071-simplify-path
0072-edit-distance
0079-word-search
0125-valid-palindrome
0127-word-ladder
0151-reverse-words-in-a-string
0168-excel-sheet-column-title
0171-excel-sheet-column-number
0205-isomorphic-strings
0208-implement-trie-prefix-tree
0242-valid-anagram
0257-binary-tree-paths
0290-word-pattern
0297-serialize-and-deserialize-binary-tree
0344-reverse-string
0345-reverse-vowels-of-a-string
0389-find-the-difference
0392-is-subsequence
0415-add-strings
0424-longest-repeating-character-replacement
0438-find-all-anagrams-in-a-string
0449-serialize-and-deserialize-bst
0451-sort-characters-by-frequency
0516-longest-palindromic-subsequence
0521-longest-uncommon-subsequence-i
0567-permutation-in-string
0583-delete-operation-for-two-strings
0680-valid-palindrome-ii
0692-top-k-frequent-words
0742-to-lower-case
0778-reorganize-string
0800-letter-case-permutation
0812-rotate-string
0874-backspace-string-compare
0886-score-of-parentheses
0961-long-pressed-name
1078-remove-outermost-parentheses
1128-remove-all-adjacent-duplicates-in-string
1160-letter-tile-possibilities
1250-longest-common-subsequence
1298-reverse-substrings-between-each-pair-of-parentheses
1437-minimum-insertion-steps-to-make-a-string-palindrome
1460-number-of-substrings-containing-all-three-characters
1537-maximum-score-after-splitting-a-string
1567-maximum-number-of-vowels-in-a-substring-of-given-length
1651-shuffle-string
1652-minimum-suffix-flips
1698-replace-all-s-to-avoid-consecutive-repeating-characters
1777-determine-if-two-strings-are-close

Sliding Window

0003-longest-substring-without-repeating-characters
0209-minimum-size-subarray-sum
0219-contains-duplicate-ii
0239-sliding-window-maximum
0413-arithmetic-slices
0424-longest-repeating-character-replacement
0438-find-all-anagrams-in-a-string
0567-permutation-in-string
0632-smallest-range-covering-elements-from-k-lists
0940-fruit-into-baskets
0966-binary-subarrays-with-sum
1034-subarrays-with-k-different-integers
1046-max-consecutive-ones-iii
1370-count-number-of-nice-subarrays
1460-number-of-substrings-containing-all-three-characters
1538-maximum-points-you-can-obtain-from-cards
1567-maximum-number-of-vowels-in-a-substring-of-given-length

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
0035-search-insert-position
0069-sqrtx
0074-search-a-2d-matrix
0081-search-in-rotated-sorted-array-ii
0153-find-minimum-in-rotated-sorted-array
0154-find-minimum-in-rotated-sorted-array-ii
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0209-minimum-size-subarray-sum
0240-search-a-2d-matrix-ii
0268-missing-number
0287-find-the-duplicate-number
0300-longest-increasing-subsequence
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0354-russian-doll-envelopes
0367-valid-perfect-square
0441-arranging-coins
0493-reverse-pairs
0532-k-diff-pairs-in-an-array
0540-single-element-in-a-sorted-array
0633-sum-of-square-numbers
0792-binary-search
0802-k-th-smallest-prime-fraction
0882-peak-index-in-a-mountain-array
0907-koko-eating-bananas
1046-max-consecutive-ones-iii
1056-capacity-to-ship-packages-within-d-days
1646-kth-missing-positive-number
1730-special-array-with-x-elements-greater-than-or-equal-x
1753-path-with-minimum-effort

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
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
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
0493-reverse-pairs
0948-sort-an-array
1014-k-closest-points-to-origin
1285-balance-a-binary-search-tree

Two Pointers

0011-container-with-most-water
0015-3sum
0016-3sum-closest
0018-4sum
0019-remove-nth-node-from-end-of-list
0026-remove-duplicates-from-sorted-array
0027-remove-element
0028-find-the-index-of-the-first-occurrence-in-a-string
0042-trapping-rain-water
0061-rotate-list
0075-sort-colors
0080-remove-duplicates-from-sorted-array-ii
0082-remove-duplicates-from-sorted-list-ii
0086-partition-list
0088-merge-sorted-array
0125-valid-palindrome
0141-linked-list-cycle
0142-linked-list-cycle-ii
0143-reorder-list
0148-sort-list
0151-reverse-words-in-a-string
0160-intersection-of-two-linked-lists
0167-two-sum-ii-input-array-is-sorted
0189-rotate-array
0202-happy-number
0234-palindrome-linked-list
0283-move-zeroes
0287-find-the-duplicate-number
0295-find-median-from-data-stream
0344-reverse-string
0345-reverse-vowels-of-a-string
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0392-is-subsequence
0455-assign-cookies
0528-swapping-nodes-in-a-linked-list
0532-k-diff-pairs-in-an-array
0567-permutation-in-string
0633-sum-of-square-numbers
0680-valid-palindrome-ii
0802-k-th-smallest-prime-fraction
0861-flipping-an-image
0874-backspace-string-compare
0875-longest-mountain-in-array
0908-middle-of-the-linked-list
0917-boats-to-save-people
0961-long-pressed-name
1019-squares-of-a-sorted-array
1798-max-number-of-k-sum-pairs

Greedy

0011-container-with-most-water
0044-wildcard-matching
0055-jump-game
0122-best-time-to-buy-and-sell-stock-ii
0134-gas-station
0135-candy
0397-integer-replacement
0435-non-overlapping-intervals
0452-minimum-number-of-arrows-to-burst-balloons
0455-assign-cookies
0502-ipo
0632-smallest-range-covering-elements-from-k-lists
0680-valid-palindrome-ii
0778-reorganize-string
0797-rabbits-in-forest
0890-lemonade-change
0891-score-after-flipping-matrix
0917-boats-to-save-people
1047-maximize-sum-of-array-after-k-negations
1285-balance-a-binary-search-tree
1448-maximum-69-number
1451-minimum-number-of-taps-to-open-to-water-a-garden
1489-pizza-with-3n-slices
1503-reducing-dishes
1652-minimum-suffix-flips
1711-find-valid-matrix-given-row-and-column-sums
1794-minimize-deviation-in-array
1829-maximum-units-on-a-truck

Trie

0014-longest-common-prefix
0208-implement-trie-prefix-tree
0386-lexicographical-numbers
0692-top-k-frequent-words

Sorting

0015-3sum
0016-3sum-closest
0018-4sum
0047-permutations-ii
0049-group-anagrams
0056-merge-intervals
0075-sort-colors
0088-merge-sorted-array
0147-insertion-sort-list
0148-sort-list
0169-majority-element
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0229-majority-element-ii
0242-valid-anagram
0268-missing-number
0274-h-index
0295-find-median-from-data-stream
0347-top-k-frequent-elements
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0354-russian-doll-envelopes
0389-find-the-difference
0435-non-overlapping-intervals
0451-sort-characters-by-frequency
0452-minimum-number-of-arrows-to-burst-balloons
0455-assign-cookies
0502-ipo
0506-relative-ranks
0532-k-diff-pairs-in-an-array
0628-maximum-product-of-three-numbers
0632-smallest-range-covering-elements-from-k-lists
0645-set-mismatch
0692-top-k-frequent-words
0778-reorganize-string
0802-k-th-smallest-prime-fraction
0917-boats-to-save-people
0948-sort-an-array
0987-reveal-cards-in-increasing-order
1014-k-closest-points-to-origin
1019-squares-of-a-sorted-array
1047-maximize-sum-of-array-after-k-negations
1217-relative-sort-array
1367-maximum-height-by-stacking-cuboids
1427-all-elements-in-two-binary-search-trees
1503-reducing-dishes
1730-special-array-with-x-elements-greater-than-or-equal-x
1777-determine-if-two-strings-are-close
1798-max-number-of-k-sum-pairs
1829-maximum-units-on-a-truck
2016-reduction-operations-to-make-the-array-elements-equal

Backtracking

0017-letter-combinations-of-a-phone-number
0037-sudoku-solver
0039-combination-sum
0040-combination-sum-ii
0046-permutations
0047-permutations-ii
0051-n-queens
0052-n-queens-ii
0078-subsets
0079-word-search
0090-subsets-ii
0113-path-sum-ii
0257-binary-tree-paths
0800-letter-case-permutation
1160-letter-tile-possibilities

Stack

0020-valid-parentheses
0042-trapping-rain-water
0071-simplify-path
0084-largest-rectangle-in-histogram
0085-maximal-rectangle
0094-binary-tree-inorder-traversal
0114-flatten-binary-tree-to-linked-list
0143-reorder-list
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0150-evaluate-reverse-polish-notation
0155-min-stack
0225-implement-stack-using-queues
0234-palindrome-linked-list
0445-add-two-numbers-ii
0496-next-greater-element-i
0503-next-greater-element-ii
0682-baseball-game
0735-asteroid-collision
0739-daily-temperatures
0874-backspace-string-compare
0886-score-of-parentheses
0933-increasing-order-search-tree
1050-construct-binary-search-tree-from-preorder-traversal
1072-next-greater-node-in-linked-list
1078-remove-outermost-parentheses
1128-remove-all-adjacent-duplicates-in-string
1298-reverse-substrings-between-each-pair-of-parentheses

Heap (Priority Queue)

0023-merge-k-sorted-lists
0215-kth-largest-element-in-an-array
0239-sliding-window-maximum
0295-find-median-from-data-stream
0347-top-k-frequent-elements
0451-sort-characters-by-frequency
0502-ipo
0506-relative-ranks
0632-smallest-range-covering-elements-from-k-lists
0692-top-k-frequent-words
0744-network-delay-time
0778-reorganize-string
0789-kth-largest-element-in-a-stream
0802-k-th-smallest-prime-fraction
0948-sort-an-array
1014-k-closest-points-to-origin
1127-last-stone-weight
1479-construct-target-array-with-multiple-sums
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1489-pizza-with-3n-slices
1753-path-with-minimum-effort
1794-minimize-deviation-in-array

Merge Sort

0023-merge-k-sorted-lists
0148-sort-list
0493-reverse-pairs
0948-sort-an-array

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string
0812-rotate-string

Matrix

0036-valid-sudoku
0037-sudoku-solver
0048-rotate-image
0054-spiral-matrix
0059-spiral-matrix-ii
0063-unique-paths-ii
0064-minimum-path-sum
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0079-word-search
0085-maximal-rectangle
0130-surrounded-regions
0200-number-of-islands
0240-search-a-2d-matrix-ii
0289-game-of-life
0417-pacific-atlantic-water-flow
0463-island-perimeter
0542-01-matrix
0695-max-area-of-island
0733-flood-fill
0741-cherry-pickup
0777-toeplitz-matrix
0861-flipping-an-image
0891-score-after-flipping-matrix
0898-transpose-matrix
1036-rotting-oranges
1073-number-of-enclaves
1104-coloring-a-border
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1711-find-valid-matrix-given-row-and-column-sums
1753-path-with-minimum-effort

Dynamic Programming

0042-trapping-rain-water
0044-wildcard-matching
0053-maximum-subarray
0055-jump-game
0062-unique-paths
0063-unique-paths-ii
0064-minimum-path-sum
0070-climbing-stairs
0072-edit-distance
0085-maximal-rectangle
0096-unique-binary-search-trees
0118-pascals-triangle
0119-pascals-triangle-ii
0120-triangle
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0123-best-time-to-buy-and-sell-stock-iii
0124-binary-tree-maximum-path-sum
0152-maximum-product-subarray
0188-best-time-to-buy-and-sell-stock-iv
0198-house-robber
0213-house-robber-ii
0300-longest-increasing-subsequence
0322-coin-change
0338-counting-bits
0354-russian-doll-envelopes
0375-guess-number-higher-or-lower-ii
0392-is-subsequence
0397-integer-replacement
0413-arithmetic-slices
0416-partition-equal-subset-sum
0435-non-overlapping-intervals
0446-arithmetic-slices-ii-subsequence
0516-longest-palindromic-subsequence
0542-01-matrix
0583-delete-operation-for-two-strings
0688-knight-probability-in-chessboard
0741-cherry-pickup
0747-min-cost-climbing-stairs
0875-longest-mountain-in-array
1008-binary-tree-cameras
1013-fibonacci-number
1236-n-th-tribonacci-number
1250-longest-common-subsequence
1263-number-of-dice-rolls-with-target-sum
1367-maximum-height-by-stacking-cuboids
1437-minimum-insertion-steps-to-make-a-string-palindrome
1451-minimum-number-of-taps-to-open-to-water-a-garden
1456-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance
1489-pizza-with-3n-slices
1503-reducing-dishes

Monotonic Stack

0042-trapping-rain-water
0084-largest-rectangle-in-histogram
0085-maximal-rectangle
0496-next-greater-element-i
0503-next-greater-element-ii
0739-daily-temperatures
1050-construct-binary-search-tree-from-preorder-traversal
1072-next-greater-node-in-linked-list

Simulation

0043-multiply-strings
0054-spiral-matrix
0059-spiral-matrix-ii
0067-add-binary
0258-add-digits
0289-game-of-life
0415-add-strings
0682-baseball-game
0735-asteroid-collision
0861-flipping-an-image
0874-backspace-string-compare
0898-transpose-matrix
0987-reveal-cards-in-increasing-order
1642-water-bottles
1951-find-the-winner-of-the-circular-game

Combinatorics

0062-unique-paths

Bit Manipulation

0067-add-binary
0078-subsets
0090-subsets-ii
0136-single-number
0137-single-number-ii
0190-reverse-bits
0191-number-of-1-bits
0231-power-of-two
0260-single-number-iii
0268-missing-number
0287-find-the-duplicate-number
0338-counting-bits
0342-power-of-four
0371-sum-of-two-integers
0389-find-the-difference
0397-integer-replacement
0461-hamming-distance
0476-number-complement
0645-set-mismatch
0795-k-th-symbol-in-grammar
0800-letter-case-permutation
0861-flipping-an-image
0891-score-after-flipping-matrix
1054-complement-of-base-10-integer
1435-xor-queries-of-a-subarray
1610-xor-operation-in-an-array
1940-maximum-xor-for-each-query

Memoization

0070-climbing-stairs
0397-integer-replacement
1013-fibonacci-number
1236-n-th-tribonacci-number

Depth-First Search

0079-word-search
0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0099-recover-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
0116-populating-next-right-pointers-in-each-node
0124-binary-tree-maximum-path-sum
0129-sum-root-to-leaf-numbers
0130-surrounded-regions
0133-clone-graph
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0199-binary-tree-right-side-view
0200-number-of-islands
0207-course-schedule
0210-course-schedule-ii
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0236-lowest-common-ancestor-of-a-binary-tree
0257-binary-tree-paths
0297-serialize-and-deserialize-binary-tree
0386-lexicographical-numbers
0404-sum-of-left-leaves
0417-pacific-atlantic-water-flow
0437-path-sum-iii
0449-serialize-and-deserialize-bst
0463-island-perimeter
0515-find-largest-value-in-each-tree-row
0530-minimum-absolute-difference-in-bst
0538-convert-bst-to-greater-tree
0543-diameter-of-binary-tree
0547-number-of-provinces
0563-binary-tree-tilt
0637-average-of-levels-in-binary-tree
0669-trim-a-binary-search-tree
0671-second-minimum-node-in-a-binary-tree
0684-redundant-connection
0687-longest-univalue-path
0695-max-area-of-island
0733-flood-fill
0744-network-delay-time
0766-flatten-a-multilevel-doubly-linked-list
0799-minimum-distance-between-bst-nodes
0801-is-graph-bipartite
0820-find-eventual-safe-states
0832-binary-tree-pruning
0871-keys-and-rooms
0893-all-nodes-distance-k-in-binary-tree
0904-leaf-similar-trees
0933-increasing-order-search-tree
0975-range-sum-of-bst
0988-flip-equivalent-binary-trees
1008-binary-tree-cameras
1021-distribute-coins-in-binary-tree
1073-number-of-enclaves
1079-sum-of-root-to-leaf-binary-numbers
1092-maximum-difference-between-node-and-ancestor
1104-coloring-a-border
1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree
1427-all-elements-in-two-binary-search-trees
1442-number-of-operations-to-make-network-connected
1484-linked-list-in-binary-tree
1753-path-with-minimum-effort

Tree

0094-binary-tree-inorder-traversal
0096-unique-binary-search-trees
0098-validate-binary-search-tree
0099-recover-binary-search-tree
0100-same-tree
0101-symmetric-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0107-binary-tree-level-order-traversal-ii
0108-convert-sorted-array-to-binary-search-tree
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
0116-populating-next-right-pointers-in-each-node
0124-binary-tree-maximum-path-sum
0129-sum-root-to-leaf-numbers
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0199-binary-tree-right-side-view
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0236-lowest-common-ancestor-of-a-binary-tree
0257-binary-tree-paths
0297-serialize-and-deserialize-binary-tree
0404-sum-of-left-leaves
0437-path-sum-iii
0449-serialize-and-deserialize-bst
0450-delete-node-in-a-bst
0515-find-largest-value-in-each-tree-row
0530-minimum-absolute-difference-in-bst
0538-convert-bst-to-greater-tree
0543-diameter-of-binary-tree
0563-binary-tree-tilt
0637-average-of-levels-in-binary-tree
0669-trim-a-binary-search-tree
0671-second-minimum-node-in-a-binary-tree
0687-longest-univalue-path
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree
0789-kth-largest-element-in-a-stream
0799-minimum-distance-between-bst-nodes
0832-binary-tree-pruning
0893-all-nodes-distance-k-in-binary-tree
0904-leaf-similar-trees
0933-increasing-order-search-tree
0975-range-sum-of-bst
0988-flip-equivalent-binary-trees
1008-binary-tree-cameras
1021-distribute-coins-in-binary-tree
1050-construct-binary-search-tree-from-preorder-traversal
1079-sum-of-root-to-leaf-binary-numbers
1092-maximum-difference-between-node-and-ancestor
1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree
1427-all-elements-in-two-binary-search-trees
1484-linked-list-in-binary-tree
1731-even-odd-tree

Binary Tree

0094-binary-tree-inorder-traversal
0096-unique-binary-search-trees
0098-validate-binary-search-tree
0099-recover-binary-search-tree
0100-same-tree
0101-symmetric-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0107-binary-tree-level-order-traversal-ii
0108-convert-sorted-array-to-binary-search-tree
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
0116-populating-next-right-pointers-in-each-node
0124-binary-tree-maximum-path-sum
0129-sum-root-to-leaf-numbers
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0199-binary-tree-right-side-view
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0236-lowest-common-ancestor-of-a-binary-tree
0257-binary-tree-paths
0297-serialize-and-deserialize-binary-tree
0404-sum-of-left-leaves
0437-path-sum-iii
0449-serialize-and-deserialize-bst
0450-delete-node-in-a-bst
0515-find-largest-value-in-each-tree-row
0530-minimum-absolute-difference-in-bst
0538-convert-bst-to-greater-tree
0543-diameter-of-binary-tree
0563-binary-tree-tilt
0637-average-of-levels-in-binary-tree
0669-trim-a-binary-search-tree
0671-second-minimum-node-in-a-binary-tree
0687-longest-univalue-path
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree
0789-kth-largest-element-in-a-stream
0799-minimum-distance-between-bst-nodes
0832-binary-tree-pruning
0893-all-nodes-distance-k-in-binary-tree
0904-leaf-similar-trees
0933-increasing-order-search-tree
0975-range-sum-of-bst
0988-flip-equivalent-binary-trees
1008-binary-tree-cameras
1021-distribute-coins-in-binary-tree
1050-construct-binary-search-tree-from-preorder-traversal
1079-sum-of-root-to-leaf-binary-numbers
1092-maximum-difference-between-node-and-ancestor
1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree
1427-all-elements-in-two-binary-search-trees
1484-linked-list-in-binary-tree
1731-even-odd-tree

Binary Search Tree

0096-unique-binary-search-trees
0098-validate-binary-search-tree
0099-recover-binary-search-tree
0108-convert-sorted-array-to-binary-search-tree
0109-convert-sorted-list-to-binary-search-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0449-serialize-and-deserialize-bst
0450-delete-node-in-a-bst
0530-minimum-absolute-difference-in-bst
0538-convert-bst-to-greater-tree
0669-trim-a-binary-search-tree
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree
0789-kth-largest-element-in-a-stream
0799-minimum-distance-between-bst-nodes
0933-increasing-order-search-tree
0975-range-sum-of-bst
1050-construct-binary-search-tree-from-preorder-traversal
1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree
1427-all-elements-in-two-binary-search-trees

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
0107-binary-tree-level-order-traversal-ii
0111-minimum-depth-of-binary-tree
0112-path-sum
0116-populating-next-right-pointers-in-each-node
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
0297-serialize-and-deserialize-binary-tree
0322-coin-change
0404-sum-of-left-leaves
0417-pacific-atlantic-water-flow
0449-serialize-and-deserialize-bst
0463-island-perimeter
0515-find-largest-value-in-each-tree-row
0530-minimum-absolute-difference-in-bst
0542-01-matrix
0547-number-of-provinces
0637-average-of-levels-in-binary-tree
0684-redundant-connection
0695-max-area-of-island
0733-flood-fill
0744-network-delay-time
0799-minimum-distance-between-bst-nodes
0801-is-graph-bipartite
0820-find-eventual-safe-states
0871-keys-and-rooms
0893-all-nodes-distance-k-in-binary-tree
1036-rotting-oranges
1073-number-of-enclaves
1104-coloring-a-border
1442-number-of-operations-to-make-network-connected
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1731-even-odd-tree
1753-path-with-minimum-effort

Union Find

0128-longest-consecutive-sequence
0130-surrounded-regions
0200-number-of-islands
0547-number-of-provinces
0684-redundant-connection
0695-max-area-of-island
0801-is-graph-bipartite
1073-number-of-enclaves
1442-number-of-operations-to-make-network-connected
1706-min-cost-to-connect-all-points
1753-path-with-minimum-effort

Graph

0133-clone-graph
0207-course-schedule
0210-course-schedule-ii
0547-number-of-provinces
0684-redundant-connection
0744-network-delay-time
0801-is-graph-bipartite
0820-find-eventual-safe-states
0871-keys-and-rooms
1442-number-of-operations-to-make-network-connected
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
1706-min-cost-to-connect-all-points
1916-find-center-of-star-graph

Design

0155-min-stack
0208-implement-trie-prefix-tree
0225-implement-stack-using-queues
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
0789-kth-largest-element-in-a-stream
0817-design-hashmap
0860-design-circular-queue
1995-finding-pairs-with-a-certain-sum

Counting

0169-majority-element
0229-majority-element-ii
0347-top-k-frequent-elements
0451-sort-characters-by-frequency
0692-top-k-frequent-words
0778-reorganize-string
1034-subarrays-with-k-different-integers
1160-letter-tile-possibilities
1620-check-if-array-pairs-are-divisible-by-k
1777-determine-if-two-strings-are-close
1925-count-nice-pairs-in-an-array

Database

0182-duplicate-emails
0183-customers-who-never-order
0196-delete-duplicate-emails
0197-rising-temperature

Enumeration

0204-count-primes
0875-longest-mountain-in-array
1656-count-good-triplets

Number Theory

0204-count-primes
0258-add-digits

Topological Sort

0207-course-schedule
0210-course-schedule-ii
0820-find-eventual-safe-states

Prefix Sum

0209-minimum-size-subarray-sum
0238-product-of-array-except-self
0303-range-sum-query-immutable
0560-subarray-sum-equals-k
0724-find-pivot-index
0966-binary-subarrays-with-sum
1046-max-consecutive-ones-iii
1206-corporate-flight-bookings
1370-count-number-of-nice-subarrays
1435-xor-queries-of-a-subarray
1514-minimum-value-to-get-positive-step-by-step-sum
1537-maximum-score-after-splitting-a-string
1538-maximum-points-you-can-obtain-from-cards
1603-running-sum-of-1d-array
1833-find-the-highest-altitude
1940-maximum-xor-for-each-query

Quickselect

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

Queue

0225-implement-stack-using-queues
0239-sliding-window-maximum
0860-design-circular-queue
0987-reveal-cards-in-increasing-order
1951-find-the-winner-of-the-circular-game

Monotonic Queue

0239-sliding-window-maximum

Counting Sort

0274-h-index
0948-sort-an-array
1217-relative-sort-array

Data Stream

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

Binary Indexed Tree

0307-range-sum-query-mutable
0493-reverse-pairs

Segment Tree

0307-range-sum-query-mutable
0493-reverse-pairs

Bucket Sort

0347-top-k-frequent-elements
0451-sort-characters-by-frequency
0692-top-k-frequent-words
0948-sort-an-array

Game Theory

0375-guess-number-higher-or-lower-ii

Doubly-Linked List

0766-flatten-a-multilevel-doubly-linked-list

Ordered Set

0493-reverse-pairs
1794-minimize-deviation-in-array

Hash Function

0817-design-hashmap

Shortest Path

0744-network-delay-time
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

Radix Sort

0948-sort-an-array

Geometry

1014-k-closest-points-to-origin
1349-check-if-it-is-a-straight-line

Minimum Spanning Tree

1706-min-cost-to-connect-all-points