Leetcode Problems

Collection of LeetCode questions to ace the coding interview!

Languages

• cpp
• python
• java
• c
• javascript
• pandas
• sql

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
0027-remove-element
0033-search-in-rotated-sorted-array
0035-search-insert-position
0041-first-missing-positive
0042-trapping-rain-water
0048-rotate-image
0049-group-anagrams
0057-insert-interval
0066-plus-one
0073-set-matrix-zeroes
0075-sort-colors
0078-subsets
0079-word-search
0081-search-in-rotated-sorted-array-ii
0085-maximal-rectangle
0088-merge-sorted-array
0108-convert-sorted-array-to-binary-search-tree
0118-pascals-triangle
0119-pascals-triangle-ii
0135-candy
0150-evaluate-reverse-polish-notation
0164-maximum-gap
0189-rotate-array
0368-largest-divisible-subset
0407-trapping-rain-water-ii
0416-partition-equal-subset-sum
0494-target-sum
0594-longest-harmonious-subsequence
0628-maximum-product-of-three-numbers
0632-smallest-range-covering-elements-from-k-lists
0682-baseball-game
0689-maximum-sum-of-3-non-overlapping-subarrays
0747-min-cost-climbing-stairs
0787-sliding-puzzle
0822-unique-morse-code-words
0854-making-a-large-island
0873-guess-the-word
0892-shortest-subarray-with-sum-at-least-k
0905-length-of-longest-fibonacci-subsequence
0934-bitwise-ors-of-subarrays
0945-snakes-and-ladders
0950-x-of-a-kind-in-a-deck-of-cards
0952-word-subsets
1002-maximum-width-ramp
1025-minimum-cost-for-tickets
1063-best-sightseeing-pair
1129-longest-string-chain
1319-unique-number-of-occurrences
1335-maximum-candies-allocated-to-k-children
1350-remove-sub-folders-from-the-filesystem
1395-minimum-time-visiting-all-points
1396-count-servers-that-communicate
1424-maximum-candies-you-can-get-from-boxes
1478-maximum-number-of-events-that-can-be-attended
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1510-find-lucky-integer-in-an-array
1524-string-matching-in-an-array
1570-final-prices-with-a-special-discount-in-a-shop
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1656-count-good-triplets
1693-sum-of-all-odd-length-subarrays
1744-number-of-ways-to-form-a-target-string-given-a-dictionary
1755-defuse-the-bomb
1813-maximum-erasure-value
1851-maximum-number-of-events-that-can-be-attended-ii
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
1923-sentence-similarity-iii
1927-maximum-ascending-subarray-sum
1995-finding-pairs-with-a-certain-sum
2035-count-sub-islands
2042-maximum-product-difference-between-two-pairs
2054-the-number-of-the-smallest-unoccupied-chair
2079-delete-duplicate-folders-in-system
2089-maximum-matrix-sum
2144-maximum-difference-between-increasing-elements
2160-minimum-operations-to-make-a-uni-value-grid
2188-minimized-maximum-of-products-distributed-to-any-store
2219-maximum-number-of-words-found-in-sentences
2229-maximum-fruits-harvested-after-at-most-k-steps
2237-longest-palindrome-by-concatenating-two-letter-words
2262-solving-questions-with-brainpower
2265-partition-array-according-to-given-pivot
2308-divide-array-into-equal-pairs
2316-count-hills-and-valleys-in-an-array
2320-find-all-k-distant-indices-in-an-array
2358-number-of-ways-to-split-array
2387-partition-array-such-that-maximum-difference-is-k
2400-minimum-score-after-removals-on-a-tree
2448-count-number-of-bad-pairs
2465-shifting-letters-ii
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2478-longest-nice-subarray
2479-meeting-rooms-iii
2502-sort-the-people
2503-longest-subarray-with-maximum-bitwise-and
2533-bitwise-xor-of-all-pairings
2551-apply-operations-to-an-array
2552-maximum-sum-of-distinct-subarrays-with-length-k
2665-minimum-time-to-repair-cars
2681-put-marbles-in-bags
2685-first-completely-painted-row-or-column
2689-rearranging-fruits
2690-house-robber-iv
2691-count-vowel-strings-in-ranges
2699-count-the-number-of-fair-pairs
2707-merge-two-2d-arrays-by-summing-values
2720-minimize-the-maximum-difference-of-pairs
2764-maximum-number-of-fish-in-a-grid
2766-find-the-prefix-common-array-of-two-arrays
2792-neighboring-bitwise-xor
2856-count-complete-subarrays-in-an-array
2888-minimum-index-of-a-valid-split
2977-check-if-a-string-is-an-acronym-of-words
3001-apply-operations-to-maximize-score
3142-longest-unequal-adjacent-groups-subsequence-ii
3152-maximum-value-of-an-ordered-triplet-ii
3154-maximum-value-of-an-ordered-triplet-i
3181-find-building-where-alice-and-bob-can-meet
3194-find-words-containing-character
3219-make-lexicographically-smallest-array-by-swapping-elements
3227-find-missing-and-repeated-values
3241-divide-array-into-arrays-with-max-difference
3307-find-the-maximum-sum-of-node-values
3309-count-prefix-and-suffix-pairs-i
3321-type-of-triangle
3372-longest-strictly-increasing-or-strictly-decreasing-subarray
3429-special-array-i
3430-count-days-without-meetings
3434-find-the-number-of-distinct-colors-among-the-balls
3476-find-minimum-operations-to-make-all-elements-divisible-by-three
3490-find-the-maximum-length-of-valid-subsequence-i
3491-find-the-maximum-length-of-valid-subsequence-ii
3501-delete-nodes-from-linked-list-present-in-array
3517-shortest-distance-after-road-addition-queries-i
3581-the-two-sneaky-numbers-of-digitville
3621-minimum-operations-to-make-array-values-equal-to-k
3639-zero-array-transformation-i
3643-zero-array-transformation-ii
3647-zero-array-transformation-iii
3648-find-the-maximum-number-of-fruits-collected
3656-minimum-number-of-operations-to-make-elements-in-array-distinct
3741-reschedule-meetings-for-maximum-free-time-ii
3743-reschedule-meetings-for-maximum-free-time-i
3747-maximum-difference-between-adjacent-elements-in-a-circular-array
3789-maximize-subarrays-after-removing-one-conflicting-pair
3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii
3795-zero-array-transformation-iv

Depth-First Search

0094-binary-tree-inorder-traversal
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
0145-binary-tree-postorder-traversal
0297-serialize-and-deserialize-binary-tree
0386-lexicographical-numbers
0449-serialize-and-deserialize-bst
0684-redundant-connection
0776-n-ary-tree-postorder-traversal
0854-making-a-large-island
0988-flip-equivalent-binary-trees
1218-lowest-common-ancestor-of-deepest-leaves
1350-remove-sub-folders-from-the-filesystem
1396-count-servers-that-communicate
1558-course-schedule-iv
2035-count-sub-islands
2246-maximum-employees-to-be-invited-to-a-meeting
2400-minimum-score-after-removals-on-a-tree
2438-find-closest-node-to-given-two-nodes
2493-reverse-odd-levels-of-binary-tree
2677-cousins-in-binary-tree-ii
2764-maximum-number-of-fish-in-a-grid
2793-count-the-number-of-complete-components
3058-maximum-number-of-k-divisible-components
3439-find-minimum-diameter-after-merging-two-trees
3645-maximize-the-number-of-target-nodes-after-connecting-trees-ii

Breadth-First Search

0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0297-serialize-and-deserialize-binary-tree
0407-trapping-rain-water-ii
0449-serialize-and-deserialize-bst
0684-redundant-connection
0787-sliding-puzzle
0854-making-a-large-island
0945-snakes-and-ladders
1218-lowest-common-ancestor-of-deepest-leaves
1396-count-servers-that-communicate
1424-maximum-candies-you-can-get-from-boxes
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1558-course-schedule-iv
1876-map-of-highest-peak
2035-count-sub-islands
2493-reverse-odd-levels-of-binary-tree
2583-divide-nodes-into-the-maximum-number-of-groups
2677-cousins-in-binary-tree-ii
2764-maximum-number-of-fish-in-a-grid
2793-count-the-number-of-complete-components
3439-find-minimum-diameter-after-merging-two-trees
3517-shortest-distance-after-road-addition-queries-i
3645-maximize-the-number-of-target-nodes-after-connecting-trees-ii

Union Find

0684-redundant-connection
0854-making-a-large-island
1058-lexicographically-smallest-equivalent-string
1396-count-servers-that-communicate
2035-count-sub-islands
2583-divide-nodes-into-the-maximum-number-of-groups
2764-maximum-number-of-fish-in-a-grid
2793-count-the-number-of-complete-components
3219-make-lexicographically-smallest-array-by-swapping-elements

Matrix

0048-rotate-image
0073-set-matrix-zeroes
0079-word-search
0085-maximal-rectangle
0407-trapping-rain-water-ii
0787-sliding-puzzle
0854-making-a-large-island
0945-snakes-and-ladders
1396-count-servers-that-communicate
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1876-map-of-highest-peak
2035-count-sub-islands
2089-maximum-matrix-sum
2160-minimum-operations-to-make-a-uni-value-grid
2685-first-completely-painted-row-or-column
2764-maximum-number-of-fish-in-a-grid
3227-find-missing-and-repeated-values
3648-find-the-maximum-number-of-fruits-collected

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0012-integer-to-roman
0013-roman-to-integer
0041-first-missing-positive
0049-group-anagrams
0073-set-matrix-zeroes
0076-minimum-window-substring
0160-intersection-of-two-linked-lists
0594-longest-harmonious-subsequence
0632-smallest-range-covering-elements-from-k-lists
0822-unique-morse-code-words
0905-length-of-longest-fibonacci-subsequence
0950-x-of-a-kind-in-a-deck-of-cards
0952-word-subsets
1129-longest-string-chain
1160-letter-tile-possibilities
1218-lowest-common-ancestor-of-deepest-leaves
1319-unique-number-of-occurrences
1502-construct-k-palindrome-strings
1510-find-lucky-integer-in-an-array
1813-maximum-erasure-value
1915-check-if-one-string-swap-can-make-strings-equal
1995-finding-pairs-with-a-certain-sum
2054-the-number-of-the-smallest-unoccupied-chair
2059-unique-length-3-palindromic-subsequences
2079-delete-duplicate-folders-in-system
2237-longest-palindrome-by-concatenating-two-letter-words
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
2502-sort-the-people
2520-using-a-robot-to-print-the-lexicographically-smallest-string
2552-maximum-sum-of-distinct-subarrays-with-length-k
2677-cousins-in-binary-tree-ii
2685-first-completely-painted-row-or-column
2689-rearranging-fruits
2707-merge-two-2d-arrays-by-summing-values
2766-find-the-prefix-common-array-of-two-arrays
2856-count-complete-subarrays-in-an-array
2888-minimum-index-of-a-valid-split
3227-find-missing-and-repeated-values
3360-minimum-deletions-to-make-string-k-special
3434-find-the-number-of-distinct-colors-among-the-balls
3445-lexicographically-minimum-string-after-removing-stars
3455-minimum-length-of-string-after-operations
3501-delete-nodes-from-linked-list-present-in-array
3548-find-the-count-of-good-integers
3569-count-of-substrings-containing-every-vowel-and-k-consonants-ii
3581-the-two-sneaky-numbers-of-digitville
3621-minimum-operations-to-make-array-values-equal-to-k
3656-minimum-number-of-operations-to-make-elements-in-array-distinct
3753-maximum-difference-between-even-and-odd-frequency-i
3754-maximum-manhattan-distance-after-k-changes
3872-find-most-frequent-vowel-and-consonant

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0083-remove-duplicates-from-sorted-list
0160-intersection-of-two-linked-lists
2903-insert-greatest-common-divisors-in-linked-list
3501-delete-nodes-from-linked-list-present-in-array

Math

0002-add-two-numbers
0007-reverse-integer
0009-palindrome-number
0012-integer-to-roman
0013-roman-to-integer
0029-divide-two-integers
0043-multiply-strings
0048-rotate-image
0050-powx-n
0066-plus-one
0067-add-binary
0069-sqrtx
0070-climbing-stairs
0150-evaluate-reverse-polish-notation
0171-excel-sheet-column-number
0189-rotate-array
0258-add-digits
0263-ugly-number
0292-nim-game
0368-largest-divisible-subset
0405-convert-a-number-to-hexadecimal
0628-maximum-product-of-three-numbers
0728-self-dividing-numbers
0873-guess-the-word
0950-x-of-a-kind-in-a-deck-of-cards
1395-minimum-time-visiting-all-points
1448-maximum-69-number
1529-max-difference-you-can-get-from-changing-an-integer
1610-xor-operation-in-an-array
1693-sum-of-all-odd-length-subarrays
1889-check-if-number-is-a-sum-of-powers-of-three
2050-count-good-numbers
2083-three-divisors
2160-minimum-operations-to-make-a-uni-value-grid
2288-count-operations-to-obtain-zero
2448-count-number-of-bad-pairs
2481-strictly-palindromic-number
2610-closest-prime-numbers-in-range
2649-count-total-number-of-colored-cells
2704-maximum-difference-by-remapping-a-digit
2903-insert-greatest-common-divisors-in-linked-list
2998-count-symmetric-integers
3001-apply-operations-to-maximize-score
3227-find-missing-and-repeated-values
3243-count-the-number-of-powerful-integers
3321-type-of-triangle
3476-find-minimum-operations-to-make-all-elements-divisible-by-three
3548-find-the-count-of-good-integers
3567-convert-date-to-binary
3581-the-two-sneaky-numbers-of-digitville
3600-find-the-k-th-character-in-string-game-i
3601-find-the-k-th-character-in-string-game-ii
3682-count-the-number-of-arrays-with-k-matching-adjacent-elements
3754-maximum-manhattan-distance-after-k-changes

Recursion

0002-add-two-numbers
0010-regular-expression-matching
0021-merge-two-sorted-lists
0050-powx-n
1197-parsing-a-boolean-expression
1667-find-kth-bit-in-nth-binary-string
2050-count-good-numbers
3600-find-the-k-th-character-in-string-game-i
3601-find-the-k-th-character-in-string-game-ii

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0006-zigzag-conversion
0008-string-to-integer-atoi
0010-regular-expression-matching
0012-integer-to-roman
0013-roman-to-integer
0014-longest-common-prefix
0020-valid-parentheses
0022-generate-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string
0038-count-and-say
0043-multiply-strings
0049-group-anagrams
0058-length-of-last-word
0067-add-binary
0076-minimum-window-substring
0079-word-search
0125-valid-palindrome
0171-excel-sheet-column-number
0297-serialize-and-deserialize-binary-tree
0344-reverse-string
0345-reverse-vowels-of-a-string
0449-serialize-and-deserialize-bst
0822-unique-morse-code-words
0873-guess-the-word
0952-word-subsets
0957-minimum-add-to-make-parentheses-valid
1058-lexicographically-smallest-equivalent-string
1128-remove-all-adjacent-duplicates-in-string
1129-longest-string-chain
1160-letter-tile-possibilities
1197-parsing-a-boolean-expression
1302-delete-characters-to-make-fancy-string
1341-split-a-string-in-balanced-strings
1350-remove-sub-folders-from-the-filesystem
1502-construct-k-palindrome-strings
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
1667-find-kth-bit-in-nth-binary-string
1744-number-of-ways-to-form-a-target-string-given-a-dictionary
1818-maximum-score-from-removing-substrings
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1915-check-if-one-string-swap-can-make-strings-equal
1923-sentence-similarity-iii
2021-remove-all-occurrences-of-a-substring
2059-unique-length-3-palindromic-subsequences
2079-delete-duplicate-folders-in-system
2095-minimum-number-of-swaps-to-make-the-string-balanced
2140-longest-subsequence-repeated-k-times
2219-maximum-number-of-words-found-in-sentences
2221-check-if-a-parentheses-string-can-be-valid
2237-longest-palindrome-by-concatenating-two-letter-words
2260-divide-a-string-into-groups-of-size-k
2395-longest-binary-subsequence-less-than-or-equal-to-k
2414-move-pieces-to-obtain-a-string
2456-construct-smallest-number-from-di-string
2465-shifting-letters-ii
2502-sort-the-people
2520-using-a-robot-to-print-the-lexicographically-smallest-string
2691-count-vowel-strings-in-ranges
2800-minimum-string-length-after-removing-substrings
2977-check-if-a-string-is-an-acronym-of-words
3142-longest-unequal-adjacent-groups-subsequence-ii
3194-find-words-containing-character
3243-count-the-number-of-powerful-integers
3309-count-prefix-and-suffix-pairs-i
3360-minimum-deletions-to-make-string-k-special
3379-score-of-a-string
3445-lexicographically-minimum-string-after-removing-stars
3447-clear-digits
3455-minimum-length-of-string-after-operations
3567-convert-date-to-binary
3569-count-of-substrings-containing-every-vowel-and-k-consonants-ii
3617-find-the-original-typed-string-i
3618-find-the-original-typed-string-ii
3683-find-the-lexicographically-largest-string-from-the-box-i
3753-maximum-difference-between-even-and-odd-frequency-i
3754-maximum-manhattan-distance-after-k-changes
3761-maximum-difference-between-even-and-odd-frequency-ii
3860-resulting-string-after-adjacent-removals
3872-find-most-frequent-vowel-and-consonant

Sliding Window

0003-longest-substring-without-repeating-characters
0076-minimum-window-substring
0594-longest-harmonious-subsequence
0632-smallest-range-covering-elements-from-k-lists
0892-shortest-subarray-with-sum-at-least-k
1755-defuse-the-bomb
1813-maximum-erasure-value
2229-maximum-fruits-harvested-after-at-most-k-steps
2478-longest-nice-subarray
2552-maximum-sum-of-distinct-subarrays-with-length-k
2856-count-complete-subarrays-in-an-array
3569-count-of-substrings-containing-every-vowel-and-k-consonants-ii
3743-reschedule-meetings-for-maximum-free-time-i
3761-maximum-difference-between-even-and-odd-frequency-ii

Binary Search

0004-median-of-two-sorted-arrays
0033-search-in-rotated-sorted-array
0035-search-insert-position
0069-sqrtx
0081-search-in-rotated-sorted-array-ii
0374-guess-number-higher-or-lower
0892-shortest-subarray-with-sum-at-least-k
1335-maximum-candies-allocated-to-k-children
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1851-maximum-number-of-events-that-can-be-attended-ii
1886-minimum-limit-of-balls-in-a-bag
2188-minimized-maximum-of-products-distributed-to-any-store
2229-maximum-fruits-harvested-after-at-most-k-steps
2665-minimum-time-to-repair-cars
2690-house-robber-iv
2699-count-the-number-of-fair-pairs
2720-minimize-the-maximum-difference-of-pairs
3181-find-building-where-alice-and-bob-can-meet
3643-zero-array-transformation-ii
3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii

Divide and Conquer

0004-median-of-two-sorted-arrays
0108-convert-sorted-array-to-binary-search-tree
0190-reverse-bits
0191-number-of-1-bits

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
0027-remove-element
0028-find-the-index-of-the-first-occurrence-in-a-string
0042-trapping-rain-water
0075-sort-colors
0088-merge-sorted-array
0125-valid-palindrome
0160-intersection-of-two-linked-lists
0189-rotate-array
0344-reverse-string
0345-reverse-vowels-of-a-string
1129-longest-string-chain
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1923-sentence-similarity-iii
2095-minimum-number-of-swaps-to-make-the-string-balanced
2265-partition-array-according-to-given-pivot
2320-find-all-k-distant-indices-in-an-array
2414-move-pieces-to-obtain-a-string
2481-strictly-palindromic-number
2551-apply-operations-to-an-array
2699-count-the-number-of-fair-pairs
2707-merge-two-2d-arrays-by-summing-values
3683-find-the-lexicographically-largest-string-from-the-box-i

Dynamic Programming

0005-longest-palindromic-substring
0010-regular-expression-matching
0022-generate-parentheses
0042-trapping-rain-water
0070-climbing-stairs
0085-maximal-rectangle
0118-pascals-triangle
0119-pascals-triangle-ii
0368-largest-divisible-subset
0416-partition-equal-subset-sum
0494-target-sum
0689-maximum-sum-of-3-non-overlapping-subarrays
0747-min-cost-climbing-stairs
0905-length-of-longest-fibonacci-subsequence
0934-bitwise-ors-of-subarrays
1025-minimum-cost-for-tickets
1063-best-sightseeing-pair
1129-longest-string-chain
1744-number-of-ways-to-form-a-target-string-given-a-dictionary
1851-maximum-number-of-events-that-can-be-attended-ii
2028-the-earliest-and-latest-rounds-where-players-compete
2262-solving-questions-with-brainpower
2395-longest-binary-subsequence-less-than-or-equal-to-k
2562-count-ways-to-build-good-strings
3142-longest-unequal-adjacent-groups-subsequence-ii
3243-count-the-number-of-powerful-integers
3307-find-the-maximum-sum-of-node-values
3490-find-the-maximum-length-of-valid-subsequence-i
3491-find-the-maximum-length-of-valid-subsequence-ii
3618-find-the-original-typed-string-ii
3648-find-the-maximum-number-of-fruits-collected
3795-zero-array-transformation-iv

Greedy

0011-container-with-most-water
0135-candy
0632-smallest-range-covering-elements-from-k-lists
0957-minimum-add-to-make-parentheses-valid
1341-split-a-string-in-balanced-strings
1448-maximum-69-number
1478-maximum-number-of-events-that-can-be-attended
1502-construct-k-palindrome-strings
1529-max-difference-you-can-get-from-changing-an-integer
1818-maximum-score-from-removing-substrings
2089-maximum-matrix-sum
2095-minimum-number-of-swaps-to-make-the-string-balanced
2140-longest-subsequence-repeated-k-times
2221-check-if-a-parentheses-string-can-be-valid
2237-longest-palindrome-by-concatenating-two-letter-words
2387-partition-array-such-that-maximum-difference-is-k
2395-longest-binary-subsequence-less-than-or-equal-to-k
2456-construct-smallest-number-from-di-string
2509-minimize-xor
2520-using-a-robot-to-print-the-lexicographically-smallest-string
2681-put-marbles-in-bags
2689-rearranging-fruits
2704-maximum-difference-by-remapping-a-digit
2720-minimize-the-maximum-difference-of-pairs
3001-apply-operations-to-maximize-score
3241-divide-array-into-arrays-with-max-difference
3307-find-the-maximum-sum-of-node-values
3360-minimum-deletions-to-make-string-k-special
3445-lexicographically-minimum-string-after-removing-stars
3647-zero-array-transformation-iii
3741-reschedule-meetings-for-maximum-free-time-ii
3743-reschedule-meetings-for-maximum-free-time-i

Trie

0014-longest-common-prefix
0386-lexicographical-numbers
0440-k-th-smallest-in-lexicographical-order
1350-remove-sub-folders-from-the-filesystem
2079-delete-duplicate-folders-in-system
3309-count-prefix-and-suffix-pairs-i

Sorting

0015-3sum
0016-3sum-closest
0049-group-anagrams
0075-sort-colors
0088-merge-sorted-array
0164-maximum-gap
0368-largest-divisible-subset
0594-longest-harmonious-subsequence
0628-maximum-product-of-three-numbers
0632-smallest-range-covering-elements-from-k-lists
1129-longest-string-chain
1478-maximum-number-of-events-that-can-be-attended
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1851-maximum-number-of-events-that-can-be-attended-ii
2042-maximum-product-difference-between-two-pairs
2160-minimum-operations-to-make-a-uni-value-grid
2387-partition-array-such-that-maximum-difference-is-k
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2479-meeting-rooms-iii
2502-sort-the-people
2681-put-marbles-in-bags
2689-rearranging-fruits
2699-count-the-number-of-fair-pairs
2888-minimum-index-of-a-valid-split
3001-apply-operations-to-maximize-score
3219-make-lexicographically-smallest-array-by-swapping-elements
3241-divide-array-into-arrays-with-max-difference
3307-find-the-maximum-sum-of-node-values
3321-type-of-triangle
3360-minimum-deletions-to-make-string-k-special
3430-count-days-without-meetings
3647-zero-array-transformation-iii

Stack

0020-valid-parentheses
0042-trapping-rain-water
0085-maximal-rectangle
0094-binary-tree-inorder-traversal
0145-binary-tree-postorder-traversal
0150-evaluate-reverse-polish-notation
0682-baseball-game
0776-n-ary-tree-postorder-traversal
0957-minimum-add-to-make-parentheses-valid
1002-maximum-width-ramp
1128-remove-all-adjacent-duplicates-in-string
1197-parsing-a-boolean-expression
1570-final-prices-with-a-special-discount-in-a-shop
1818-maximum-score-from-removing-substrings
2021-remove-all-occurrences-of-a-substring
2095-minimum-number-of-swaps-to-make-the-string-balanced
2221-check-if-a-parentheses-string-can-be-valid
2456-construct-smallest-number-from-di-string
2520-using-a-robot-to-print-the-lexicographically-smallest-string
2800-minimum-string-length-after-removing-substrings
3001-apply-operations-to-maximize-score
3181-find-building-where-alice-and-bob-can-meet
3445-lexicographically-minimum-string-after-removing-stars
3447-clear-digits
3860-resulting-string-after-adjacent-removals

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string
1524-string-matching-in-an-array
3309-count-prefix-and-suffix-pairs-i

Bit Manipulation

0029-divide-two-integers
0067-add-binary
0078-subsets
0190-reverse-bits
0191-number-of-1-bits
0405-convert-a-number-to-hexadecimal
0934-bitwise-ors-of-subarrays
1610-xor-operation-in-an-array
2059-unique-length-3-palindromic-subsequences
2308-divide-array-into-equal-pairs
2400-minimum-score-after-removals-on-a-tree
2478-longest-nice-subarray
2503-longest-subarray-with-maximum-bitwise-and
2509-minimize-xor
2533-bitwise-xor-of-all-pairings
2766-find-the-prefix-common-array-of-two-arrays
2792-neighboring-bitwise-xor
3307-find-the-maximum-sum-of-node-values
3600-find-the-k-th-character-in-string-game-i
3601-find-the-k-th-character-in-string-game-ii

Monotonic Stack

0042-trapping-rain-water
0085-maximal-rectangle
1002-maximum-width-ramp
1570-final-prices-with-a-special-discount-in-a-shop
3001-apply-operations-to-maximize-score
3181-find-building-where-alice-and-bob-can-meet

Simulation

0043-multiply-strings
0067-add-binary
0258-add-digits
0682-baseball-game
1667-find-kth-bit-in-nth-binary-string
2021-remove-all-occurrences-of-a-substring
2260-divide-a-string-into-groups-of-size-k
2265-partition-array-according-to-given-pivot
2288-count-operations-to-obtain-zero
2479-meeting-rooms-iii
2551-apply-operations-to-an-array
2800-minimum-string-length-after-removing-substrings
3434-find-the-number-of-distinct-colors-among-the-balls
3447-clear-digits
3600-find-the-k-th-character-in-string-game-i
3790-fruits-into-baskets-ii
3860-resulting-string-after-adjacent-removals

Memoization

0070-climbing-stairs
2028-the-earliest-and-latest-rounds-where-players-compete
2395-longest-binary-subsequence-less-than-or-equal-to-k

Backtracking

0022-generate-parentheses
0078-subsets
0079-word-search
0494-target-sum
1160-letter-tile-possibilities
1516-the-k-th-lexicographical-string-of-all-happy-strings-of-length-n
2140-longest-subsequence-repeated-k-times
2456-construct-smallest-number-from-di-string

Tree

0094-binary-tree-inorder-traversal
0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0108-convert-sorted-array-to-binary-search-tree
0110-balanced-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0145-binary-tree-postorder-traversal
0297-serialize-and-deserialize-binary-tree
0449-serialize-and-deserialize-bst
0776-n-ary-tree-postorder-traversal
0988-flip-equivalent-binary-trees
1218-lowest-common-ancestor-of-deepest-leaves
2400-minimum-score-after-removals-on-a-tree
2493-reverse-odd-levels-of-binary-tree
2677-cousins-in-binary-tree-ii
3058-maximum-number-of-k-divisible-components
3307-find-the-maximum-sum-of-node-values
3439-find-minimum-diameter-after-merging-two-trees
3645-maximize-the-number-of-target-nodes-after-connecting-trees-ii

Binary Tree

0094-binary-tree-inorder-traversal
0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0108-convert-sorted-array-to-binary-search-tree
0110-balanced-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0145-binary-tree-postorder-traversal
0297-serialize-and-deserialize-binary-tree
0449-serialize-and-deserialize-bst
0988-flip-equivalent-binary-trees
1218-lowest-common-ancestor-of-deepest-leaves
2493-reverse-odd-levels-of-binary-tree
2677-cousins-in-binary-tree-ii

Number Theory

0258-add-digits
0950-x-of-a-kind-in-a-deck-of-cards
2083-three-divisors
2610-closest-prime-numbers-in-range
2903-insert-greatest-common-divisors-in-linked-list
3001-apply-operations-to-maximize-score

Heap (Priority Queue)

0407-trapping-rain-water-ii
0632-smallest-range-covering-elements-from-k-lists
0892-shortest-subarray-with-sum-at-least-k
1478-maximum-number-of-events-that-can-be-attended
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
2054-the-number-of-the-smallest-unoccupied-chair
2434-design-a-number-container-system
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2479-meeting-rooms-iii
2681-put-marbles-in-bags
3181-find-building-where-alice-and-bob-can-meet
3445-lexicographically-minimum-string-after-removing-stars
3647-zero-array-transformation-iii

Interactive

0374-guess-number-higher-or-lower
0873-guess-the-word

Queue

0892-shortest-subarray-with-sum-at-least-k

Prefix Sum

0892-shortest-subarray-with-sum-at-least-k
1537-maximum-score-after-splitting-a-string
1693-sum-of-all-odd-length-subarrays
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
2059-unique-length-3-palindromic-subsequences
2229-maximum-fruits-harvested-after-at-most-k-steps
2358-number-of-ways-to-split-array
2465-shifting-letters-ii
2691-count-vowel-strings-in-ranges
3618-find-the-original-typed-string-ii
3639-zero-array-transformation-i
3643-zero-array-transformation-ii
3647-zero-array-transformation-iii
3761-maximum-difference-between-even-and-odd-frequency-ii
3789-maximize-subarrays-after-removing-one-conflicting-pair

Monotonic Queue

0892-shortest-subarray-with-sum-at-least-k

Graph

0684-redundant-connection
1424-maximum-candies-you-can-get-from-boxes
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1558-course-schedule-iv
2246-maximum-employees-to-be-invited-to-a-meeting
2438-find-closest-node-to-given-two-nodes
2583-divide-nodes-into-the-maximum-number-of-groups
2793-count-the-number-of-complete-components
3189-find-champion-ii
3439-find-minimum-diameter-after-merging-two-trees
3517-shortest-distance-after-road-addition-queries-i

Binary Indexed Tree

3181-find-building-where-alice-and-bob-can-meet

Segment Tree

3181-find-building-where-alice-and-bob-can-meet
3789-maximize-subarrays-after-removing-one-conflicting-pair
3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii

Database

0175-combine-two-tables
0181-employees-earning-more-than-their-managers
0182-duplicate-emails
0595-big-countries
1258-article-views-i
1908-recyclable-and-low-fat-products

Binary Search Tree

0108-convert-sorted-array-to-binary-search-tree
0449-serialize-and-deserialize-bst

Rolling Hash

3309-count-prefix-and-suffix-pairs-i

Hash Function

2079-delete-duplicate-folders-in-system
3309-count-prefix-and-suffix-pairs-i

Counting

0594-longest-harmonious-subsequence
0950-x-of-a-kind-in-a-deck-of-cards
1160-letter-tile-possibilities
1341-split-a-string-in-balanced-strings
1396-count-servers-that-communicate
1502-construct-k-palindrome-strings
1510-find-lucky-integer-in-an-array
1915-check-if-one-string-swap-can-make-strings-equal
2140-longest-subsequence-repeated-k-times
2237-longest-palindrome-by-concatenating-two-letter-words
2308-divide-array-into-equal-pairs
2448-count-number-of-bad-pairs
3360-minimum-deletions-to-make-string-k-special
3455-minimum-length-of-string-after-operations
3753-maximum-difference-between-even-and-odd-frequency-i
3754-maximum-manhattan-distance-after-k-changes
3872-find-most-frequent-vowel-and-consonant

Brainteaser

0292-nim-game
2481-strictly-palindromic-number
2503-longest-subarray-with-maximum-bitwise-and
2533-bitwise-xor-of-all-pairings

Shortest Path

1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid

Topological Sort

1558-course-schedule-iv
2246-maximum-employees-to-be-invited-to-a-meeting

Game Theory

0292-nim-game
0873-guess-the-word

Design

0297-serialize-and-deserialize-binary-tree
0449-serialize-and-deserialize-bst
1995-finding-pairs-with-a-certain-sum
2434-design-a-number-container-system

Ordered Set

2434-design-a-number-container-system
3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii

Enumeration

1656-count-good-triplets
2083-three-divisors
2140-longest-subsequence-repeated-k-times
2998-count-symmetric-integers
3548-find-the-count-of-good-integers
3683-find-the-lexicographically-largest-string-from-the-box-i
3741-reschedule-meetings-for-maximum-free-time-ii
3761-maximum-difference-between-even-and-odd-frequency-ii
3789-maximize-subarrays-after-removing-one-conflicting-pair

Geometry

1395-minimum-time-visiting-all-points

Combinatorics

3548-find-the-count-of-good-integers
3682-count-the-number-of-arrays-with-k-matching-adjacent-elements

Bucket Sort

0164-maximum-gap

Radix Sort

0164-maximum-gap