Leetcode

Tree

1114-binary-search-tree-to-greater-sum-tree

Depth-First Search

1114-binary-search-tree-to-greater-sum-tree

Binary Search Tree

1114-binary-search-tree-to-greater-sum-tree

Binary Tree

1114-binary-search-tree-to-greater-sum-tree

Graph

1916-find-center-of-star-graph

LeetCode Topics

Array

0001-two-sum
0004-median-of-two-sorted-arrays
0011-container-with-most-water
0015-3sum
0016-3sum-closest
0026-remove-duplicates-from-sorted-array
0031-next-permutation
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0039-combination-sum
0040-combination-sum-ii
0041-first-missing-positive
0042-trapping-rain-water
0045-jump-game-ii
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
0057-insert-interval
0063-unique-paths-ii
0064-minimum-path-sum
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0075-sort-colors
0078-subsets
0079-word-search
0081-search-in-rotated-sorted-array-ii
0084-largest-rectangle-in-histogram
0088-merge-sorted-array
0090-subsets-ii
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0108-convert-sorted-array-to-binary-search-tree
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
0130-surrounded-regions
0134-gas-station
0139-word-break
0140-word-break-ii
0149-max-points-on-a-line
0150-evaluate-reverse-polish-notation
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0163-missing-ranges
0174-dungeon-game
0188-best-time-to-buy-and-sell-stock-iv
0198-house-robber
0200-number-of-islands
0209-minimum-size-subarray-sum
0213-house-robber-ii
0215-kth-largest-element-in-an-array
0216-combination-sum-iii
0221-maximal-square
0238-product-of-array-except-self
0239-sliding-window-maximum
0247-strobogrammatic-number-ii
0252-meeting-rooms
0253-meeting-rooms-ii
0256-paint-house
0259-3sum-smaller
0265-paint-house-ii
0268-missing-number
0287-find-the-duplicate-number
0300-longest-increasing-subsequence
0303-range-sum-query-immutable
0309-best-time-to-buy-and-sell-stock-with-cooldown
0312-burst-balloons
0315-count-of-smaller-numbers-after-self
0322-coin-change
0325-maximum-size-subarray-sum-equals-k
0329-longest-increasing-path-in-a-matrix
0347-top-k-frequent-elements
0350-intersection-of-two-arrays-ii
0373-find-k-pairs-with-smallest-sums
0377-combination-sum-iv
0378-kth-smallest-element-in-a-sorted-matrix
0399-evaluate-division
0407-trapping-rain-water-ii
0410-split-array-largest-sum
0416-partition-equal-subset-sum
0442-find-all-duplicates-in-an-array
0448-find-all-numbers-disappeared-in-an-array
0455-assign-cookies
0457-circular-array-loop
0463-island-perimeter
0480-sliding-window-median
0487-max-consecutive-ones-ii
0494-target-sum
0496-next-greater-element-i
0498-diagonal-traverse
0502-ipo
0503-next-greater-element-ii
0518-coin-change-ii
0540-single-element-in-a-sorted-array
0542-01-matrix
0546-remove-boxes
0560-subarray-sum-equals-k
0581-shortest-unsorted-continuous-subarray
0611-valid-triangle-number
0621-task-scheduler
0643-maximum-average-subarray-i
0645-set-mismatch
0646-maximum-length-of-pair-chain
0648-replace-words
0658-find-k-closest-elements
0673-number-of-longest-increasing-subsequence
0689-maximum-sum-of-3-non-overlapping-subarrays
0692-top-k-frequent-words
0695-max-area-of-island
0698-partition-to-k-equal-sum-subsets
0713-subarray-product-less-than-k
0714-best-time-to-buy-and-sell-stock-with-transaction-fee
0721-accounts-merge
0733-flood-fill
0735-asteroid-collision
0739-daily-temperatures
0740-delete-and-earn
0745-find-smallest-letter-greater-than-target
0747-min-cost-climbing-stairs
0780-max-chunks-to-make-sorted
0786-search-in-a-sorted-array-of-unknown-size
0792-binary-search
0797-rabbits-in-forest
0802-k-th-smallest-prime-fraction
0854-making-a-large-island
0882-peak-index-in-a-mountain-array
0905-length-of-longest-fibonacci-subsequence
0907-koko-eating-bananas
0917-boats-to-save-people
0925-construct-binary-tree-from-preorder-and-postorder-traversal
0932-monotonic-array
0940-fruit-into-baskets
0948-sort-an-array
0952-word-subsets
0954-maximum-sum-circular-subarray
0966-binary-subarrays-with-sum
0967-minimum-falling-path-sum
1002-maximum-width-ramp
1014-k-closest-points-to-origin
1016-subarray-sums-divisible-by-k
1019-squares-of-a-sorted-array
1025-minimum-cost-for-tickets
1032-satisfiability-of-equality-equations
1034-subarrays-with-k-different-integers
1036-rotting-oranges
1042-minimum-cost-to-merge-stones
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
1063-best-sightseeing-pair
1073-number-of-enclaves
1075-index-pairs-of-a-string
1087-longest-arithmetic-subsequence
1095-two-city-scheduling
1098-largest-unique-number
1105-uncrossed-lines
1126-minimum-cost-to-connect-sticks
1127-last-stone-weight
1141-how-many-apples-can-you-put-into-the-basket
1171-shortest-path-in-binary-matrix
1185-find-in-mountain-array
1192-divide-chocolate
1196-filling-bookcase-shelves
1200-remove-interval
1207-delete-nodes-and-return-forest
1228-minimum-cost-tree-from-leaf-values
1293-three-consecutive-odds
1306-minimum-absolute-difference
1330-longest-arithmetic-subsequence-of-given-difference
1364-tuple-with-same-product
1370-count-number-of-nice-subarrays
1380-number-of-closed-islands
1396-count-servers-that-communicate
1397-search-suggestions-system
1408-find-the-smallest-divisor-given-a-threshold
1428-jump-game-iii
1468-check-if-n-and-its-double-exist
1477-product-of-the-last-k-numbers
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1514-minimum-value-to-get-positive-step-by-step-sum
1524-string-matching-in-an-array
1538-maximum-points-you-can-obtain-from-cards
1539-diagonal-traverse-ii
1570-final-prices-with-a-special-discount-in-a-shop
1586-longest-subarray-of-1s-after-deleting-one-element
1603-running-sum-of-1d-array
1604-least-number-of-unique-integers-after-k-removals
1605-minimum-number-of-days-to-make-m-bouquets
1615-range-sum-of-sorted-subarray-sums
1616-minimum-difference-between-largest-and-smallest-value-in-three-moves
1631-number-of-sub-arrays-with-odd-sum
1646-kth-missing-positive-number
1693-sum-of-all-odd-length-subarrays
1744-number-of-ways-to-form-a-target-string-given-a-dictionary
1776-minimum-operations-to-reduce-x-to-zero
1787-sum-of-absolute-differences-in-a-sorted-array
1819-construct-the-lexicographically-largest-valid-sequence
1829-maximum-units-on-a-truck
1833-find-the-highest-altitude
1845-largest-submatrix-with-rearrangements
1849-maximum-absolute-sum-of-any-subarray
1876-map-of-highest-peak
1878-check-if-array-is-sorted-and-rotated
1886-minimum-limit-of-balls-in-a-bag
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1909-buildings-with-an-ocean-view
1917-maximum-average-pass-ratio
1927-maximum-ascending-subarray-sum
2089-maximum-matrix-sum
2094-remove-stones-to-minimize-the-total
2096-find-the-longest-valid-obstacle-course-at-each-position
2102-find-the-middle-index-in-array
2107-find-unique-binary-string
2145-grid-game
2164-two-best-non-overlapping-events
2180-maximum-number-of-tasks-you-can-assign
2220-find-all-possible-recipes-from-given-supplies
2232-adding-spaces-to-a-string
2255-minimum-swaps-to-group-all-1s-together-ii
2262-solving-questions-with-brainpower
2265-partition-array-according-to-given-pivot
2292-counting-words-with-a-given-prefix
2306-create-binary-tree-from-descriptions
2308-divide-array-into-equal-pairs
2310-minimum-operations-to-halve-array-sum
2358-number-of-ways-to-split-array
2387-partition-array-such-that-maximum-difference-is-k
2448-count-number-of-bad-pairs
2465-shifting-letters-ii
2469-longest-subsequence-with-limited-sum
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2478-longest-nice-subarray
2479-meeting-rooms-iii
2533-bitwise-xor-of-all-pairings
2538-minimum-cost-to-make-array-equal
2551-apply-operations-to-an-array
2552-maximum-sum-of-distinct-subarrays-with-length-k
2564-most-profitable-path-in-a-tree
2614-maximum-count-of-positive-integer-and-negative-integer
2640-maximum-number-of-integers-to-choose-from-a-range-i
2648-number-of-ways-to-earn-points
2665-minimum-time-to-repair-cars
2685-first-completely-painted-row-or-column
2690-house-robber-iv
2691-count-vowel-strings-in-ranges
2692-take-gifts-from-the-richest-pile
2695-find-score-of-an-array-after-marking-all-elements
2707-merge-two-2d-arrays-by-summing-values
2714-left-and-right-sum-differences
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
2846-robot-collisions
2868-continuous-subarrays
2891-maximum-beauty-of-an-array-after-applying-operation
2917-count-pairs-whose-sum-is-less-than-target
3181-find-building-where-alice-and-bob-can-meet
3219-make-lexicographically-smallest-array-by-swapping-elements
3227-find-missing-and-repeated-values
3235-minimum-cost-to-convert-string-i
3248-count-the-number-of-incremovable-subarrays-ii
3309-count-prefix-and-suffix-pairs-i
3332-minimum-operations-to-exceed-threshold-value-ii
3348-minimum-cost-walk-in-weighted-graph
3372-longest-strictly-increasing-or-strictly-decreasing-subarray
3427-special-array-ii
3429-special-array-i
3434-find-the-number-of-distinct-colors-among-the-balls
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3483-alternating-groups-ii
3555-final-array-state-after-k-multiplication-operations-i
3643-zero-array-transformation-ii

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
0041-first-missing-positive
0049-group-anagrams
0073-set-matrix-zeroes
0076-minimum-window-substring
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0127-word-ladder
0133-clone-graph
0139-word-break
0140-word-break-ii
0141-linked-list-cycle
0142-linked-list-cycle-ii
0146-lru-cache
0149-max-points-on-a-line
0166-fraction-to-recurring-decimal
0202-happy-number
0208-implement-trie-prefix-tree
0246-strobogrammatic-number
0268-missing-number
0325-maximum-size-subarray-sum-equals-k
0340-longest-substring-with-at-most-k-distinct-characters
0347-top-k-frequent-elements
0350-intersection-of-two-arrays-ii
0383-ransom-note
0387-first-unique-character-in-a-string
0409-longest-palindrome
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
0457-circular-array-loop
0460-lfu-cache
0480-sliding-window-median
0496-next-greater-element-i
0560-subarray-sum-equals-k
0567-permutation-in-string
0621-task-scheduler
0645-set-mismatch
0648-replace-words
0692-top-k-frequent-words
0721-accounts-merge
0726-number-of-atoms
0740-delete-and-earn
0797-rabbits-in-forest
0893-all-nodes-distance-k-in-binary-tree
0905-length-of-longest-fibonacci-subsequence
0925-construct-binary-tree-from-preorder-and-postorder-traversal
0940-fruit-into-baskets
0952-word-subsets
0966-binary-subarrays-with-sum
0984-most-stones-removed-with-same-row-or-column
1016-subarray-sums-divisible-by-k
1034-subarrays-with-k-different-integers
1087-longest-arithmetic-subsequence
1098-largest-unique-number
1125-design-file-system
1160-letter-tile-possibilities
1207-delete-nodes-and-return-forest
1297-maximum-number-of-balloons
1330-longest-arithmetic-subsequence-of-given-difference
1364-tuple-with-same-product
1370-count-number-of-nice-subarrays
1387-find-elements-in-a-contaminated-binary-tree
1468-check-if-n-and-its-double-exist
1469-minimum-number-of-steps-to-make-two-strings-anagram
1502-construct-k-palindrome-strings
1554-minimum-time-to-collect-all-apples-in-a-tree
1604-least-number-of-unique-integers-after-k-removals
1770-minimum-deletions-to-make-character-frequencies-unique
1776-minimum-operations-to-reduce-x-to-zero
1777-determine-if-two-strings-are-close
1915-check-if-one-string-swap-can-make-strings-equal
2059-unique-length-3-palindromic-subsequences
2107-find-unique-binary-string
2220-find-all-possible-recipes-from-given-supplies
2293-minimum-number-of-steps-to-make-two-strings-anagram-ii
2300-construct-string-with-repeat-limit
2306-create-binary-tree-from-descriptions
2308-divide-array-into-equal-pairs
2434-design-a-number-container-system
2448-count-number-of-bad-pairs
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2479-meeting-rooms-iii
2552-maximum-sum-of-distinct-subarrays-with-length-k
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
2707-merge-two-2d-arrays-by-summing-values
2755-extra-characters-in-a-string
2766-find-the-prefix-common-array-of-two-arrays
3227-find-missing-and-repeated-values
3267-find-longest-special-substring-that-occurs-thrice-i
3434-find-the-number-of-distinct-colors-among-the-balls
3455-minimum-length-of-string-after-operations
3569-count-of-substrings-containing-every-vowel-and-k-consonants-ii

Two Pointers

0005-longest-palindromic-substring
0011-container-with-most-water
0015-3sum
0016-3sum-closest
0019-remove-nth-node-from-end-of-list
0026-remove-duplicates-from-sorted-array
0028-find-the-index-of-the-first-occurrence-in-a-string
0031-next-permutation
0042-trapping-rain-water
0061-rotate-list
0075-sort-colors
0086-partition-list
0088-merge-sorted-array
0125-valid-palindrome
0141-linked-list-cycle
0142-linked-list-cycle-ii
0143-reorder-list
0151-reverse-words-in-a-string
0202-happy-number
0246-strobogrammatic-number
0253-meeting-rooms-ii
0259-3sum-smaller
0277-find-the-celebrity
0287-find-the-duplicate-number
0295-find-median-from-data-stream
0350-intersection-of-two-arrays-ii
0392-is-subsequence
0443-string-compression
0455-assign-cookies
0457-circular-array-loop
0567-permutation-in-string
0581-shortest-unsorted-continuous-subarray
0611-valid-triangle-number
0647-palindromic-substrings
0658-find-k-closest-elements
0680-valid-palindrome-ii
0802-k-th-smallest-prime-fraction
0874-backspace-string-compare
0917-boats-to-save-people
1002-maximum-width-ramp
1019-squares-of-a-sorted-array
1356-minimum-number-of-moves-to-make-palindrome
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
1997-next-palindrome-using-same-digits
2232-adding-spaces-to-a-string
2265-partition-array-according-to-given-pivot
2414-move-pieces-to-obtain-a-string
2551-apply-operations-to-an-array
2707-merge-two-2d-arrays-by-summing-values
2917-count-pairs-whose-sum-is-less-than-target
3018-make-string-a-subsequence-using-cyclic-increments
3248-count-the-number-of-incremovable-subarrays-ii

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
0081-search-in-rotated-sorted-array-ii
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0209-minimum-size-subarray-sum
0259-3sum-smaller
0268-missing-number
0270-closest-binary-search-tree-value
0287-find-the-duplicate-number
0300-longest-increasing-subsequence
0315-count-of-smaller-numbers-after-self
0350-intersection-of-two-arrays-ii
0378-kth-smallest-element-in-a-sorted-matrix
0410-split-array-largest-sum
0540-single-element-in-a-sorted-array
0611-valid-triangle-number
0658-find-k-closest-elements
0713-subarray-product-less-than-k
0745-find-smallest-letter-greater-than-target
0786-search-in-a-sorted-array-of-unknown-size
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
1060-longest-repeating-substring
1087-longest-arithmetic-subsequence
1185-find-in-mountain-array
1192-divide-chocolate
1397-search-suggestions-system
1408-find-the-smallest-divisor-given-a-threshold
1468-check-if-n-and-its-double-exist
1605-minimum-number-of-days-to-make-m-bouquets
1615-range-sum-of-sorted-subarray-sums
1646-kth-missing-positive-number
1776-minimum-operations-to-reduce-x-to-zero
1886-minimum-limit-of-balls-in-a-bag
2096-find-the-longest-valid-obstacle-course-at-each-position
2164-two-best-non-overlapping-events
2180-maximum-number-of-tasks-you-can-assign
2469-longest-subsequence-with-limited-sum
2538-minimum-cost-to-make-array-equal
2614-maximum-count-of-positive-integer-and-negative-integer
2640-maximum-number-of-integers-to-choose-from-a-range-i
2665-minimum-time-to-repair-cars
2690-house-robber-iv
2891-maximum-beauty-of-an-array-after-applying-operation
2917-count-pairs-whose-sum-is-less-than-target
3181-find-building-where-alice-and-bob-can-meet
3248-count-the-number-of-incremovable-subarrays-ii
3267-find-longest-special-substring-that-occurs-thrice-i
3427-special-array-ii
3643-zero-array-transformation-ii

Sorting

0015-3sum
0016-3sum-closest
0047-permutations-ii
0049-group-anagrams
0056-merge-intervals
0075-sort-colors
0088-merge-sorted-array
0215-kth-largest-element-in-an-array
0252-meeting-rooms
0253-meeting-rooms-ii
0259-3sum-smaller
0268-missing-number
0295-find-median-from-data-stream
0347-top-k-frequent-elements
0350-intersection-of-two-arrays-ii
0378-kth-smallest-element-in-a-sorted-matrix
0451-sort-characters-by-frequency
0455-assign-cookies
0502-ipo
0581-shortest-unsorted-continuous-subarray
0611-valid-triangle-number
0621-task-scheduler
0642-design-search-autocomplete-system
0645-set-mismatch
0646-maximum-length-of-pair-chain
0658-find-k-closest-elements
0692-top-k-frequent-words
0721-accounts-merge
0726-number-of-atoms
0780-max-chunks-to-make-sorted
0802-k-th-smallest-prime-fraction
0917-boats-to-save-people
0948-sort-an-array
1014-k-closest-points-to-origin
1019-squares-of-a-sorted-array
1047-maximize-sum-of-array-after-k-negations
1075-index-pairs-of-a-string
1095-two-city-scheduling
1098-largest-unique-number
1141-how-many-apples-can-you-put-into-the-basket
1306-minimum-absolute-difference
1397-search-suggestions-system
1468-check-if-n-and-its-double-exist
1539-diagonal-traverse-ii
1604-least-number-of-unique-integers-after-k-removals
1615-range-sum-of-sorted-subarray-sums
1616-minimum-difference-between-largest-and-smallest-value-in-three-moves
1770-minimum-deletions-to-make-character-frequencies-unique
1777-determine-if-two-strings-are-close
1829-maximum-units-on-a-truck
1845-largest-submatrix-with-rearrangements
2164-two-best-non-overlapping-events
2180-maximum-number-of-tasks-you-can-assign
2387-partition-array-such-that-maximum-difference-is-k
2469-longest-subsequence-with-limited-sum
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2479-meeting-rooms-iii
2538-minimum-cost-to-make-array-equal
2640-maximum-number-of-integers-to-choose-from-a-range-i
2695-find-score-of-an-array-after-marking-all-elements
2846-robot-collisions
2891-maximum-beauty-of-an-array-after-applying-operation
2917-count-pairs-whose-sum-is-less-than-target
3219-make-lexicographically-smallest-array-by-swapping-elements

Greedy

0011-container-with-most-water
0045-jump-game-ii
0055-jump-game
0122-best-time-to-buy-and-sell-stock-ii
0134-gas-station
0253-meeting-rooms-ii
0316-remove-duplicate-letters
0402-remove-k-digits
0409-longest-palindrome
0410-split-array-largest-sum
0455-assign-cookies
0502-ipo
0581-shortest-unsorted-continuous-subarray
0611-valid-triangle-number
0621-task-scheduler
0646-maximum-length-of-pair-chain
0680-valid-palindrome-ii
0714-best-time-to-buy-and-sell-stock-with-transaction-fee
0780-max-chunks-to-make-sorted
0797-rabbits-in-forest
0917-boats-to-save-people
1047-maximize-sum-of-array-after-k-negations
1095-two-city-scheduling
1126-minimum-cost-to-connect-sticks
1141-how-many-apples-can-you-put-into-the-basket
1159-smallest-subsequence-of-distinct-characters
1228-minimum-cost-tree-from-leaf-values
1356-minimum-number-of-moves-to-make-palindrome
1448-maximum-69-number
1502-construct-k-palindrome-strings
1604-least-number-of-unique-integers-after-k-removals
1616-minimum-difference-between-largest-and-smallest-value-in-three-moves
1770-minimum-deletions-to-make-character-frequencies-unique
1782-smallest-string-with-a-given-numeric-value
1818-maximum-score-from-removing-substrings
1829-maximum-units-on-a-truck
1845-largest-submatrix-with-rearrangements
1917-maximum-average-pass-ratio
2089-maximum-matrix-sum
2094-remove-stones-to-minimize-the-total
2180-maximum-number-of-tasks-you-can-assign
2221-check-if-a-parentheses-string-can-be-valid
2300-construct-string-with-repeat-limit
2310-minimum-operations-to-halve-array-sum
2387-partition-array-such-that-maximum-difference-is-k
2456-construct-smallest-number-from-di-string
2469-longest-subsequence-with-limited-sum
2509-minimize-xor
2538-minimum-cost-to-make-array-equal
2640-maximum-number-of-integers-to-choose-from-a-range-i
2817-minimum-cost-to-make-all-characters-equal

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0008-string-to-integer-atoi
0012-integer-to-roman
0013-roman-to-integer
0014-longest-common-prefix
0017-letter-combinations-of-a-phone-number
0020-valid-parentheses
0022-generate-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string
0049-group-anagrams
0072-edit-distance
0076-minimum-window-substring
0079-word-search
0097-interleaving-string
0115-distinct-subsequences
0125-valid-palindrome
0127-word-ladder
0131-palindrome-partitioning
0132-palindrome-partitioning-ii
0139-word-break
0140-word-break-ii
0151-reverse-words-in-a-string
0166-fraction-to-recurring-decimal
0208-implement-trie-prefix-tree
0224-basic-calculator
0241-different-ways-to-add-parentheses
0246-strobogrammatic-number
0247-strobogrammatic-number-ii
0316-remove-duplicate-letters
0320-generalized-abbreviation
0340-longest-substring-with-at-most-k-distinct-characters
0383-ransom-note
0387-first-unique-character-in-a-string
0392-is-subsequence
0394-decode-string
0399-evaluate-division
0402-remove-k-digits
0409-longest-palindrome
0424-longest-repeating-character-replacement
0438-find-all-anagrams-in-a-string
0443-string-compression
0451-sort-characters-by-frequency
0516-longest-palindromic-subsequence
0567-permutation-in-string
0583-delete-operation-for-two-strings
0642-design-search-autocomplete-system
0647-palindromic-substrings
0648-replace-words
0680-valid-palindrome-ii
0686-repeated-string-match
0692-top-k-frequent-words
0712-minimum-ascii-delete-sum-for-two-strings
0721-accounts-merge
0726-number-of-atoms
0727-minimum-window-subsequence
0800-letter-case-permutation
0874-backspace-string-compare
0952-word-subsets
1032-satisfiability-of-equality-equations
1060-longest-repeating-substring
1075-index-pairs-of-a-string
1093-recover-a-tree-from-preorder-traversal
1125-design-file-system
1128-remove-all-adjacent-duplicates-in-string
1159-smallest-subsequence-of-distinct-characters
1160-letter-tile-possibilities
1170-shortest-common-supersequence
1250-longest-common-subsequence
1297-maximum-number-of-balloons
1298-reverse-substrings-between-each-pair-of-parentheses
1320-remove-all-adjacent-duplicates-in-string-ii
1356-minimum-number-of-moves-to-make-palindrome
1371-minimum-remove-to-make-valid-parentheses
1397-search-suggestions-system
1437-minimum-insertion-steps-to-make-a-string-palindrome
1469-minimum-number-of-steps-to-make-two-strings-anagram
1502-construct-k-palindrome-strings
1508-longest-happy-prefix
1516-the-k-th-lexicographical-string-of-all-happy-strings-of-length-n
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
1744-number-of-ways-to-form-a-target-string-given-a-dictionary
1756-minimum-deletions-to-make-string-balanced
1770-minimum-deletions-to-make-character-frequencies-unique
1777-determine-if-two-strings-are-close
1782-smallest-string-with-a-given-numeric-value
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
1997-next-palindrome-using-same-digits
2021-remove-all-occurrences-of-a-substring
2059-unique-length-3-palindromic-subsequences
2107-find-unique-binary-string
2217-step-by-step-directions-from-a-binary-tree-node-to-another
2220-find-all-possible-recipes-from-given-supplies
2221-check-if-a-parentheses-string-can-be-valid
2232-adding-spaces-to-a-string
2292-counting-words-with-a-given-prefix
2293-minimum-number-of-steps-to-make-two-strings-anagram-ii
2300-construct-string-with-repeat-limit
2414-move-pieces-to-obtain-a-string
2456-construct-smallest-number-from-di-string
2463-minimum-recolors-to-get-k-consecutive-black-blocks
2465-shifting-letters-ii
2691-count-vowel-strings-in-ranges
2727-number-of-senior-citizens
2755-extra-characters-in-a-string
2817-minimum-cost-to-make-all-characters-equal
3018-make-string-a-subsequence-using-cyclic-increments
3235-minimum-cost-to-convert-string-i
3267-find-longest-special-substring-that-occurs-thrice-i
3309-count-prefix-and-suffix-pairs-i
3447-clear-digits
3455-minimum-length-of-string-after-operations
3569-count-of-substrings-containing-every-vowel-and-k-consonants-ii

Stack

0020-valid-parentheses
0042-trapping-rain-water
0084-largest-rectangle-in-histogram
0114-flatten-binary-tree-to-linked-list
0143-reorder-list
0144-binary-tree-preorder-traversal
0150-evaluate-reverse-polish-notation
0224-basic-calculator
0232-implement-queue-using-stacks
0316-remove-duplicate-letters
0394-decode-string
0402-remove-k-digits
0496-next-greater-element-i
0503-next-greater-element-ii
0581-shortest-unsorted-continuous-subarray
0726-number-of-atoms
0735-asteroid-collision
0739-daily-temperatures
0776-n-ary-tree-postorder-traversal
0780-max-chunks-to-make-sorted
0874-backspace-string-compare
0937-online-stock-span
1002-maximum-width-ramp
1050-construct-binary-search-tree-from-preorder-traversal
1128-remove-all-adjacent-duplicates-in-string
1159-smallest-subsequence-of-distinct-characters
1228-minimum-cost-tree-from-leaf-values
1298-reverse-substrings-between-each-pair-of-parentheses
1320-remove-all-adjacent-duplicates-in-string-ii
1371-minimum-remove-to-make-valid-parentheses
1570-final-prices-with-a-special-discount-in-a-shop
1756-minimum-deletions-to-make-string-balanced
1818-maximum-score-from-removing-substrings
1909-buildings-with-an-ocean-view
2021-remove-all-occurrences-of-a-substring
2221-check-if-a-parentheses-string-can-be-valid
2456-construct-smallest-number-from-di-string
2573-remove-nodes-from-linked-list
2846-robot-collisions
3181-find-building-where-alice-and-bob-can-meet
3447-clear-digits

Simulation

0054-spiral-matrix
0498-diagonal-traverse
0735-asteroid-collision
0874-backspace-string-compare
2021-remove-all-occurrences-of-a-substring
2232-adding-spaces-to-a-string
2265-partition-array-according-to-given-pivot
2479-meeting-rooms-iii
2551-apply-operations-to-an-array
2692-take-gifts-from-the-richest-pile
2695-find-score-of-an-array-after-marking-all-elements
2846-robot-collisions
3332-minimum-operations-to-exceed-threshold-value-ii
3434-find-the-number-of-distinct-colors-among-the-balls
3447-clear-digits
3555-final-array-state-after-k-multiplication-operations-i

Tree

0095-unique-binary-search-trees-ii
0096-unique-binary-search-trees
0098-validate-binary-search-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
0107-binary-tree-level-order-traversal-ii
0108-convert-sorted-array-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
0117-populating-next-right-pointers-in-each-node-ii
0124-binary-tree-maximum-path-sum
0129-sum-root-to-leaf-numbers
0144-binary-tree-preorder-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
0270-closest-binary-search-tree-value
0285-inorder-successor-in-bst
0337-house-robber-iii
0437-path-sum-iii
0450-delete-node-in-a-bst
0515-find-largest-value-in-each-tree-row
0530-minimum-absolute-difference-in-bst
0543-diameter-of-binary-tree
0545-boundary-of-binary-tree
0637-average-of-levels-in-binary-tree
0776-n-ary-tree-postorder-traversal
0784-insert-into-a-binary-search-tree
0893-all-nodes-distance-k-in-binary-tree
0925-construct-binary-tree-from-preorder-and-postorder-traversal
0975-range-sum-of-bst
0988-flip-equivalent-binary-trees
1035-cousins-in-binary-tree
1050-construct-binary-search-tree-from-preorder-traversal
1092-maximum-difference-between-node-and-ancestor
1093-recover-a-tree-from-preorder-traversal
1207-delete-nodes-and-return-forest
1254-deepest-leaves-sum
1387-find-elements-in-a-contaminated-binary-tree
1432-check-if-a-string-is-a-valid-sequence-from-root-to-leaves-path-in-a-binary-tree
1544-count-good-nodes-in-binary-tree
1554-minimum-time-to-collect-all-apples-in-a-tree
1653-number-of-good-leaf-nodes-pairs
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
2564-most-profitable-path-in-a-tree
2677-cousins-in-binary-tree-ii
3058-maximum-number-of-k-divisible-components
3439-find-minimum-diameter-after-merging-two-trees

Binary Tree

0095-unique-binary-search-trees-ii
0096-unique-binary-search-trees
0098-validate-binary-search-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
0107-binary-tree-level-order-traversal-ii
0108-convert-sorted-array-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
0117-populating-next-right-pointers-in-each-node-ii
0124-binary-tree-maximum-path-sum
0129-sum-root-to-leaf-numbers
0144-binary-tree-preorder-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
0270-closest-binary-search-tree-value
0285-inorder-successor-in-bst
0337-house-robber-iii
0437-path-sum-iii
0450-delete-node-in-a-bst
0515-find-largest-value-in-each-tree-row
0530-minimum-absolute-difference-in-bst
0543-diameter-of-binary-tree
0545-boundary-of-binary-tree
0637-average-of-levels-in-binary-tree
0784-insert-into-a-binary-search-tree
0893-all-nodes-distance-k-in-binary-tree
0925-construct-binary-tree-from-preorder-and-postorder-traversal
0975-range-sum-of-bst
0988-flip-equivalent-binary-trees
1035-cousins-in-binary-tree
1050-construct-binary-search-tree-from-preorder-traversal
1092-maximum-difference-between-node-and-ancestor
1093-recover-a-tree-from-preorder-traversal
1207-delete-nodes-and-return-forest
1254-deepest-leaves-sum
1387-find-elements-in-a-contaminated-binary-tree
1432-check-if-a-string-is-a-valid-sequence-from-root-to-leaves-path-in-a-binary-tree
1544-count-good-nodes-in-binary-tree
1653-number-of-good-leaf-nodes-pairs
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
2677-cousins-in-binary-tree-ii

Depth-First Search

0098-validate-binary-search-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
0117-populating-next-right-pointers-in-each-node-ii
0124-binary-tree-maximum-path-sum
0129-sum-root-to-leaf-numbers
0130-surrounded-regions
0133-clone-graph
0144-binary-tree-preorder-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
0270-closest-binary-search-tree-value
0285-inorder-successor-in-bst
0323-number-of-connected-components-in-an-undirected-graph
0329-longest-increasing-path-in-a-matrix
0337-house-robber-iii
0399-evaluate-division
0437-path-sum-iii
0463-island-perimeter
0515-find-largest-value-in-each-tree-row
0530-minimum-absolute-difference-in-bst
0543-diameter-of-binary-tree
0545-boundary-of-binary-tree
0547-number-of-provinces
0637-average-of-levels-in-binary-tree
0642-design-search-autocomplete-system
0684-redundant-connection
0695-max-area-of-island
0721-accounts-merge
0733-flood-fill
0776-n-ary-tree-postorder-traversal
0813-all-paths-from-source-to-target
0820-find-eventual-safe-states
0854-making-a-large-island
0893-all-nodes-distance-k-in-binary-tree
0975-range-sum-of-bst
0984-most-stones-removed-with-same-row-or-column
0988-flip-equivalent-binary-trees
1035-cousins-in-binary-tree
1073-number-of-enclaves
1092-maximum-difference-between-node-and-ancestor
1093-recover-a-tree-from-preorder-traversal
1207-delete-nodes-and-return-forest
1254-deepest-leaves-sum
1380-number-of-closed-islands
1387-find-elements-in-a-contaminated-binary-tree
1396-count-servers-that-communicate
1428-jump-game-iii
1432-check-if-a-string-is-a-valid-sequence-from-root-to-leaves-path-in-a-binary-tree
1442-number-of-operations-to-make-network-connected
1544-count-good-nodes-in-binary-tree
1554-minimum-time-to-collect-all-apples-in-a-tree
1558-course-schedule-iv
1653-number-of-good-leaf-nodes-pairs
2121-find-if-path-exists-in-graph
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
2564-most-profitable-path-in-a-tree
2582-minimum-score-of-a-path-between-two-cities
2677-cousins-in-binary-tree-ii
2764-maximum-number-of-fish-in-a-grid
3058-maximum-number-of-k-divisible-components
3439-find-minimum-diameter-after-merging-two-trees

Sliding Window

0003-longest-substring-without-repeating-characters
0076-minimum-window-substring
0209-minimum-size-subarray-sum
0239-sliding-window-maximum
0340-longest-substring-with-at-most-k-distinct-characters
0424-longest-repeating-character-replacement
0438-find-all-anagrams-in-a-string
0480-sliding-window-median
0487-max-consecutive-ones-ii
0567-permutation-in-string
0643-maximum-average-subarray-i
0658-find-k-closest-elements
0713-subarray-product-less-than-k
0727-minimum-window-subsequence
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
1538-maximum-points-you-can-obtain-from-cards
1586-longest-subarray-of-1s-after-deleting-one-element
1776-minimum-operations-to-reduce-x-to-zero
2255-minimum-swaps-to-group-all-1s-together-ii
2463-minimum-recolors-to-get-k-consecutive-black-blocks
2478-longest-nice-subarray
2552-maximum-sum-of-distinct-subarrays-with-length-k
2868-continuous-subarrays
2891-maximum-beauty-of-an-array-after-applying-operation
3267-find-longest-special-substring-that-occurs-thrice-i
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3483-alternating-groups-ii
3569-count-of-substrings-containing-every-vowel-and-k-consonants-ii

Monotonic Stack

0042-trapping-rain-water
0084-largest-rectangle-in-histogram
0316-remove-duplicate-letters
0402-remove-k-digits
0496-next-greater-element-i
0503-next-greater-element-ii
0581-shortest-unsorted-continuous-subarray
0739-daily-temperatures
0780-max-chunks-to-make-sorted
0937-online-stock-span
1002-maximum-width-ramp
1050-construct-binary-search-tree-from-preorder-traversal
1159-smallest-subsequence-of-distinct-characters
1228-minimum-cost-tree-from-leaf-values
1570-final-prices-with-a-special-discount-in-a-shop
1909-buildings-with-an-ocean-view
2573-remove-nodes-from-linked-list
3181-find-building-where-alice-and-bob-can-meet

Math

0002-add-two-numbers
0007-reverse-integer
0009-palindrome-number
0012-integer-to-roman
0013-roman-to-integer
0048-rotate-image
0060-permutation-sequence
0062-unique-paths
0069-sqrtx
0070-climbing-stairs
0096-unique-binary-search-trees
0149-max-points-on-a-line
0150-evaluate-reverse-polish-notation
0166-fraction-to-recurring-decimal
0202-happy-number
0223-rectangle-area
0224-basic-calculator
0241-different-ways-to-add-parentheses
0268-missing-number
0279-perfect-squares
0797-rabbits-in-forest
0866-rectangle-overlap
1013-fibonacci-number
1014-k-closest-points-to-origin
1236-n-th-tribonacci-number
1370-count-number-of-nice-subarrays
1448-maximum-69-number
1477-product-of-the-last-k-numbers
1631-number-of-sub-arrays-with-odd-sum
1693-sum-of-all-odd-length-subarrays
1787-sum-of-absolute-differences-in-a-sorted-array
1889-check-if-number-is-a-sum-of-powers-of-three
2448-count-number-of-bad-pairs
2610-closest-prime-numbers-in-range
2649-count-total-number-of-colored-cells
2802-find-the-punishment-number-of-an-integer
3227-find-missing-and-repeated-values
3555-final-array-state-after-k-multiplication-operations-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
0215-kth-largest-element-in-an-array
0315-count-of-smaller-numbers-after-self
0347-top-k-frequent-elements
0925-construct-binary-tree-from-preorder-and-postorder-traversal
0948-sort-an-array
0954-maximum-sum-circular-subarray
1014-k-closest-points-to-origin

Geometry

0149-max-points-on-a-line
0223-rectangle-area
0866-rectangle-overlap
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
0253-meeting-rooms-ii
0295-find-median-from-data-stream
0347-top-k-frequent-elements
0373-find-k-pairs-with-smallest-sums
0378-kth-smallest-element-in-a-sorted-matrix
0407-trapping-rain-water-ii
0451-sort-characters-by-frequency
0480-sliding-window-median
0502-ipo
0621-task-scheduler
0642-design-search-autocomplete-system
0658-find-k-closest-elements
0692-top-k-frequent-words
0802-k-th-smallest-prime-fraction
0948-sort-an-array
1014-k-closest-points-to-origin
1126-minimum-cost-to-connect-sticks
1127-last-stone-weight
1397-search-suggestions-system
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1539-diagonal-traverse-ii
1917-maximum-average-pass-ratio
2094-remove-stones-to-minimize-the-total
2164-two-best-non-overlapping-events
2300-construct-string-with-repeat-limit
2310-minimum-operations-to-halve-array-sum
2434-design-a-number-container-system
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2479-meeting-rooms-iii
2692-take-gifts-from-the-richest-pile
2695-find-score-of-an-array-after-marking-all-elements
2868-continuous-subarrays
3181-find-building-where-alice-and-bob-can-meet
3332-minimum-operations-to-exceed-threshold-value-ii
3555-final-array-state-after-k-multiplication-operations-i

Quickselect

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

Merge Sort

0023-merge-k-sorted-lists
0315-count-of-smaller-numbers-after-self
0948-sort-an-array

Bucket Sort

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

Radix Sort

0948-sort-an-array

Counting Sort

0347-top-k-frequent-elements
0383-ransom-note
0387-first-unique-character-in-a-string
0451-sort-characters-by-frequency
0621-task-scheduler
0692-top-k-frequent-words
0948-sort-an-array
1034-subarrays-with-k-different-integers
1160-letter-tile-possibilities
1297-maximum-number-of-balloons
1364-tuple-with-same-product
1396-count-servers-that-communicate
1469-minimum-number-of-steps-to-make-two-strings-anagram
1502-construct-k-palindrome-strings
1604-least-number-of-unique-integers-after-k-removals
1777-determine-if-two-strings-are-close
1915-check-if-one-string-swap-can-make-strings-equal
2293-minimum-number-of-steps-to-make-two-strings-anagram-ii
2300-construct-string-with-repeat-limit
2308-divide-array-into-equal-pairs
2448-count-number-of-bad-pairs
2614-maximum-count-of-positive-integer-and-negative-integer
3267-find-longest-special-substring-that-occurs-thrice-i
3455-minimum-length-of-string-after-operations

Database

0176-second-highest-salary
0181-employees-earning-more-than-their-managers
0182-duplicate-emails
0184-department-highest-salary
0185-department-top-three-salaries
0196-delete-duplicate-emails
0197-rising-temperature
0570-managers-with-at-least-5-direct-reports
0577-employee-bonus
0584-find-customer-referee
0595-big-countries
0596-classes-more-than-5-students
0619-biggest-single-number
0620-not-boring-movies
1135-customers-who-bought-all-products
1153-product-sales-analysis-i
1155-product-sales-analysis-iii
1161-project-employees-i
1258-article-views-i
1292-immediate-food-delivery-ii
1317-monthly-transactions-i
1390-average-selling-price
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
1877-find-followers-count
1882-the-number-of-employees-which-report-to-each-employee
1908-recyclable-and-low-fat-products
2087-confirmation-rate
2127-employees-whose-manager-left-the-company
2495-number-of-unique-subjects-taught-by-each-teacher
2516-sort-the-olympic-table

Dynamic Programming

0005-longest-palindromic-substring
0022-generate-parentheses
0042-trapping-rain-water
0045-jump-game-ii
0053-maximum-subarray
0055-jump-game
0062-unique-paths
0063-unique-paths-ii
0064-minimum-path-sum
0070-climbing-stairs
0072-edit-distance
0095-unique-binary-search-trees-ii
0096-unique-binary-search-trees
0097-interleaving-string
0115-distinct-subsequences
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
0131-palindrome-partitioning
0132-palindrome-partitioning-ii
0139-word-break
0140-word-break-ii
0174-dungeon-game
0188-best-time-to-buy-and-sell-stock-iv
0198-house-robber
0213-house-robber-ii
0221-maximal-square
0241-different-ways-to-add-parentheses
0256-paint-house
0265-paint-house-ii
0279-perfect-squares
0300-longest-increasing-subsequence
0309-best-time-to-buy-and-sell-stock-with-cooldown
0312-burst-balloons
0322-coin-change
0329-longest-increasing-path-in-a-matrix
0337-house-robber-iii
0377-combination-sum-iv
0392-is-subsequence
0410-split-array-largest-sum
0416-partition-equal-subset-sum
0487-max-consecutive-ones-ii
0494-target-sum
0516-longest-palindromic-subsequence
0518-coin-change-ii
0542-01-matrix
0546-remove-boxes
0583-delete-operation-for-two-strings
0646-maximum-length-of-pair-chain
0647-palindromic-substrings
0673-number-of-longest-increasing-subsequence
0689-maximum-sum-of-3-non-overlapping-subarrays
0698-partition-to-k-equal-sum-subsets
0712-minimum-ascii-delete-sum-for-two-strings
0714-best-time-to-buy-and-sell-stock-with-transaction-fee
0727-minimum-window-subsequence
0740-delete-and-earn
0747-min-cost-climbing-stairs
0806-domino-and-tromino-tiling
0905-length-of-longest-fibonacci-subsequence
0954-maximum-sum-circular-subarray
0967-minimum-falling-path-sum
1013-fibonacci-number
1025-minimum-cost-for-tickets
1042-minimum-cost-to-merge-stones
1060-longest-repeating-substring
1063-best-sightseeing-pair
1087-longest-arithmetic-subsequence
1105-uncrossed-lines
1170-shortest-common-supersequence
1196-filling-bookcase-shelves
1228-minimum-cost-tree-from-leaf-values
1236-n-th-tribonacci-number
1250-longest-common-subsequence
1330-longest-arithmetic-subsequence-of-given-difference
1332-count-vowels-permutation
1437-minimum-insertion-steps-to-make-a-string-palindrome
1456-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance
1586-longest-subarray-of-1s-after-deleting-one-element
1631-number-of-sub-arrays-with-odd-sum
1744-number-of-ways-to-form-a-target-string-given-a-dictionary
1756-minimum-deletions-to-make-string-balanced
1849-maximum-absolute-sum-of-any-subarray
2164-two-best-non-overlapping-events
2262-solving-questions-with-brainpower
2562-count-ways-to-build-good-strings
2648-number-of-ways-to-earn-points
2755-extra-characters-in-a-string
2817-minimum-cost-to-make-all-characters-equal

Graph

0133-clone-graph
0207-course-schedule
0210-course-schedule-ii
0277-find-the-celebrity
0323-number-of-connected-components-in-an-undirected-graph
0329-longest-increasing-path-in-a-matrix
0399-evaluate-division
0547-number-of-provinces
0684-redundant-connection
0813-all-paths-from-source-to-target
0820-find-eventual-safe-states
0984-most-stones-removed-with-same-row-or-column
1032-satisfiability-of-equality-equations
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
1558-course-schedule-iv
2121-find-if-path-exists-in-graph
2220-find-all-possible-recipes-from-given-supplies
2246-maximum-employees-to-be-invited-to-a-meeting
2564-most-profitable-path-in-a-tree
2582-minimum-score-of-a-path-between-two-cities
2583-divide-nodes-into-the-maximum-number-of-groups
3235-minimum-cost-to-convert-string-i
3348-minimum-cost-walk-in-weighted-graph
3439-find-minimum-diameter-after-merging-two-trees

Shortest Path

0399-evaluate-division
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
3235-minimum-cost-to-convert-string-i

Prefix Sum

0209-minimum-size-subarray-sum
0238-product-of-array-except-self
0253-meeting-rooms-ii
0303-range-sum-query-immutable
0325-maximum-size-subarray-sum-equals-k
0410-split-array-largest-sum
0560-subarray-sum-equals-k
0713-subarray-product-less-than-k
0966-binary-subarrays-with-sum
1016-subarray-sums-divisible-by-k
1042-minimum-cost-to-merge-stones
1046-max-consecutive-ones-iii
1370-count-number-of-nice-subarrays
1477-product-of-the-last-k-numbers
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
1631-number-of-sub-arrays-with-odd-sum
1693-sum-of-all-odd-length-subarrays
1776-minimum-operations-to-reduce-x-to-zero
1787-sum-of-absolute-differences-in-a-sorted-array
1833-find-the-highest-altitude
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
2059-unique-length-3-palindromic-subsequences
2102-find-the-middle-index-in-array
2145-grid-game
2358-number-of-ways-to-split-array
2465-shifting-letters-ii
2469-longest-subsequence-with-limited-sum
2538-minimum-cost-to-make-array-equal
2691-count-vowel-strings-in-ranges
2714-left-and-right-sum-differences
3427-special-array-ii
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3643-zero-array-transformation-ii

Queue

0232-implement-queue-using-stacks
0239-sliding-window-maximum
0387-first-unique-character-in-a-string
0954-maximum-sum-circular-subarray
2180-maximum-number-of-tasks-you-can-assign
2868-continuous-subarrays
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i

Monotonic Queue

0239-sliding-window-maximum
0954-maximum-sum-circular-subarray
2180-maximum-number-of-tasks-you-can-assign
2868-continuous-subarrays

Bit Manipulation

0078-subsets
0090-subsets-ii
0268-missing-number
0287-find-the-duplicate-number
0320-generalized-abbreviation
0645-set-mismatch
0698-partition-to-k-equal-sum-subsets
0800-letter-case-permutation
2059-unique-length-3-palindromic-subsequences
2308-divide-array-into-equal-pairs
2478-longest-nice-subarray
2509-minimize-xor
2533-bitwise-xor-of-all-pairings
2766-find-the-prefix-common-array-of-two-arrays
3348-minimum-cost-walk-in-weighted-graph
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i

Matrix

0048-rotate-image
0054-spiral-matrix
0063-unique-paths-ii
0064-minimum-path-sum
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0079-word-search
0130-surrounded-regions
0174-dungeon-game
0200-number-of-islands
0221-maximal-square
0329-longest-increasing-path-in-a-matrix
0378-kth-smallest-element-in-a-sorted-matrix
0407-trapping-rain-water-ii
0463-island-perimeter
0498-diagonal-traverse
0542-01-matrix
0695-max-area-of-island
0733-flood-fill
0854-making-a-large-island
0967-minimum-falling-path-sum
1036-rotting-oranges
1073-number-of-enclaves
1171-shortest-path-in-binary-matrix
1380-number-of-closed-islands
1396-count-servers-that-communicate
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1845-largest-submatrix-with-rearrangements
1876-map-of-highest-peak
2089-maximum-matrix-sum
2145-grid-game
2685-first-completely-painted-row-or-column
2764-maximum-number-of-fish-in-a-grid
3227-find-missing-and-repeated-values

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0023-merge-k-sorted-lists
0024-swap-nodes-in-pairs
0025-reverse-nodes-in-k-group
0061-rotate-list
0086-partition-list
0092-reverse-linked-list-ii
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0141-linked-list-cycle
0142-linked-list-cycle-ii
0143-reorder-list
0146-lru-cache
0206-reverse-linked-list
0460-lfu-cache
2573-remove-nodes-from-linked-list

Recursion

0002-add-two-numbers
0024-swap-nodes-in-pairs
0025-reverse-nodes-in-k-group
0060-permutation-sequence
0143-reorder-list
0206-reverse-linked-list
0224-basic-calculator
0241-different-ways-to-add-parentheses
0247-strobogrammatic-number-ii
0394-decode-string
1013-fibonacci-number
2573-remove-nodes-from-linked-list

Breadth-First Search

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
0117-populating-next-right-pointers-in-each-node-ii
0127-word-ladder
0130-surrounded-regions
0133-clone-graph
0199-binary-tree-right-side-view
0200-number-of-islands
0207-course-schedule
0210-course-schedule-ii
0226-invert-binary-tree
0279-perfect-squares
0322-coin-change
0323-number-of-connected-components-in-an-undirected-graph
0329-longest-increasing-path-in-a-matrix
0399-evaluate-division
0407-trapping-rain-water-ii
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
0721-accounts-merge
0733-flood-fill
0813-all-paths-from-source-to-target
0820-find-eventual-safe-states
0854-making-a-large-island
0893-all-nodes-distance-k-in-binary-tree
1007-numbers-with-same-consecutive-differences
1035-cousins-in-binary-tree
1036-rotting-oranges
1073-number-of-enclaves
1171-shortest-path-in-binary-matrix
1254-deepest-leaves-sum
1380-number-of-closed-islands
1387-find-elements-in-a-contaminated-binary-tree
1396-count-servers-that-communicate
1428-jump-game-iii
1432-check-if-a-string-is-a-valid-sequence-from-root-to-leaves-path-in-a-binary-tree
1442-number-of-operations-to-make-network-connected
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1544-count-good-nodes-in-binary-tree
1554-minimum-time-to-collect-all-apples-in-a-tree
1558-course-schedule-iv
1876-map-of-highest-peak
2121-find-if-path-exists-in-graph
2493-reverse-odd-levels-of-binary-tree
2558-minimum-number-of-operations-to-sort-a-binary-tree-by-level
2564-most-profitable-path-in-a-tree
2582-minimum-score-of-a-path-between-two-cities
2583-divide-nodes-into-the-maximum-number-of-groups
2677-cousins-in-binary-tree-ii
2764-maximum-number-of-fish-in-a-grid
3439-find-minimum-diameter-after-merging-two-trees

Backtracking

0017-letter-combinations-of-a-phone-number
0022-generate-parentheses
0039-combination-sum
0040-combination-sum-ii
0046-permutations
0047-permutations-ii
0051-n-queens
0077-combinations
0078-subsets
0079-word-search
0090-subsets-ii
0095-unique-binary-search-trees-ii
0113-path-sum-ii
0131-palindrome-partitioning
0140-word-break-ii
0216-combination-sum-iii
0254-factor-combinations
0320-generalized-abbreviation
0494-target-sum
0698-partition-to-k-equal-sum-subsets
0800-letter-case-permutation
0813-all-paths-from-source-to-target
1007-numbers-with-same-consecutive-differences
1160-letter-tile-possibilities
1516-the-k-th-lexicographical-string-of-all-happy-strings-of-length-n
1819-construct-the-lexicographically-largest-valid-sequence
2107-find-unique-binary-string
2456-construct-smallest-number-from-di-string
2802-find-the-punishment-number-of-an-integer

Memoization

0070-climbing-stairs
0139-word-break
0140-word-break-ii
0241-different-ways-to-add-parentheses
0329-longest-increasing-path-in-a-matrix
0546-remove-boxes
0698-partition-to-k-equal-sum-subsets
1013-fibonacci-number
1236-n-th-tribonacci-number

Binary Search Tree

0095-unique-binary-search-trees-ii
0096-unique-binary-search-trees
0098-validate-binary-search-tree
0108-convert-sorted-array-to-binary-search-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0270-closest-binary-search-tree-value
0285-inorder-successor-in-bst
0450-delete-node-in-a-bst
0530-minimum-absolute-difference-in-bst
0784-insert-into-a-binary-search-tree
0975-range-sum-of-bst
1050-construct-binary-search-tree-from-preorder-traversal

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string
0686-repeated-string-match
1508-longest-happy-prefix
1524-string-matching-in-an-array
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
2292-counting-words-with-a-given-prefix
3309-count-prefix-and-suffix-pairs-i

Union Find

0130-surrounded-regions
0200-number-of-islands
0323-number-of-connected-components-in-an-undirected-graph
0399-evaluate-division
0547-number-of-provinces
0684-redundant-connection
0695-max-area-of-island
0721-accounts-merge
0854-making-a-large-island
0984-most-stones-removed-with-same-row-or-column
1032-satisfiability-of-equality-equations
1073-number-of-enclaves
1380-number-of-closed-islands
1396-count-servers-that-communicate
1442-number-of-operations-to-make-network-connected
2121-find-if-path-exists-in-graph
2582-minimum-score-of-a-path-between-two-cities
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
3348-minimum-cost-walk-in-weighted-graph

Combinatorics

0062-unique-paths

Trie

0014-longest-common-prefix
0139-word-break
0140-word-break-ii
0208-implement-trie-prefix-tree
0642-design-search-autocomplete-system
0648-replace-words
0692-top-k-frequent-words
1075-index-pairs-of-a-string
1125-design-file-system
1397-search-suggestions-system
2755-extra-characters-in-a-string
3309-count-prefix-and-suffix-pairs-i

Binary Indexed Tree

0315-count-of-smaller-numbers-after-self
0673-number-of-longest-increasing-subsequence
1356-minimum-number-of-moves-to-make-palindrome
2096-find-the-longest-valid-obstacle-course-at-each-position
3181-find-building-where-alice-and-bob-can-meet

Segment Tree

0315-count-of-smaller-numbers-after-self
0673-number-of-longest-increasing-subsequence
3181-find-building-where-alice-and-bob-can-meet

Design

0146-lru-cache
0208-implement-trie-prefix-tree
0232-implement-queue-using-stacks
0295-find-median-from-data-stream
0303-range-sum-query-immutable
0460-lfu-cache
0642-design-search-autocomplete-system
0937-online-stock-span
1125-design-file-system
1387-find-elements-in-a-contaminated-binary-tree
1477-product-of-the-last-k-numbers
2434-design-a-number-container-system

Data Stream

0295-find-median-from-data-stream
0642-design-search-autocomplete-system
0937-online-stock-span
1477-product-of-the-last-k-numbers

Topological Sort

0207-course-schedule
0210-course-schedule-ii
0329-longest-increasing-path-in-a-matrix
0820-find-eventual-safe-states
1558-course-schedule-iv
2220-find-all-possible-recipes-from-given-supplies
2246-maximum-employees-to-be-invited-to-a-meeting

Bitmask

0698-partition-to-k-equal-sum-subsets

Interactive

0277-find-the-celebrity
0786-search-in-a-sorted-array-of-unknown-size
1185-find-in-mountain-array

Ordered Set

0315-count-of-smaller-numbers-after-self
2434-design-a-number-container-system
2868-continuous-subarrays

Rolling Hash

1060-longest-repeating-substring
1508-longest-happy-prefix
3309-count-prefix-and-suffix-pairs-i

Hash Function

1060-longest-repeating-substring
1508-longest-happy-prefix
3309-count-prefix-and-suffix-pairs-i

Brainteaser

2533-bitwise-xor-of-all-pairings

Doubly-Linked List

0146-lru-cache
0460-lfu-cache

Suffix Array

1060-longest-repeating-substring

Number Theory

2610-closest-prime-numbers-in-range