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
0015-3sum
0018-4sum
0026-remove-duplicates-from-sorted-array
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0041-first-missing-positive
0046-permutations
0048-rotate-image
0049-group-anagrams
0053-maximum-subarray
0054-spiral-matrix
0056-merge-intervals
0057-insert-interval
0059-spiral-matrix-ii
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0075-sort-colors
0079-word-search
0080-remove-duplicates-from-sorted-array-ii
0081-search-in-rotated-sorted-array-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
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0128-longest-consecutive-sequence
0130-surrounded-regions
0136-single-number
0137-single-number-ii
0150-evaluate-reverse-polish-notation
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0189-rotate-array
0200-number-of-islands
0204-count-primes
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0229-majority-element-ii
0238-product-of-array-except-self
0240-search-a-2d-matrix-ii
0260-single-number-iii
0268-missing-number
0274-h-index
0275-h-index-ii
0283-move-zeroes
0284-peeking-iterator
0287-find-the-duplicate-number
0289-game-of-life
0329-longest-increasing-path-in-a-matrix
0347-top-k-frequent-elements
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0380-insert-delete-getrandom-o1
0381-insert-delete-getrandom-o1-duplicates-allowed
0384-shuffle-an-array
0396-rotate-function
0399-evaluate-division
0413-arithmetic-slices
0414-third-maximum-number
0417-pacific-atlantic-water-flow
0419-battleships-in-a-board
0442-find-all-duplicates-in-an-array
0448-find-all-numbers-disappeared-in-an-array
0455-assign-cookies
0457-circular-array-loop
0485-max-consecutive-ones
0498-diagonal-traverse
0503-next-greater-element-ii
0529-minesweeper
0540-single-element-in-a-sorted-array
0561-array-partition
0566-reshape-the-matrix
0575-distribute-candies
0594-longest-harmonious-subsequence
0654-maximum-binary-tree
0690-employee-importance
0692-top-k-frequent-words
0695-max-area-of-island
0720-longest-word-in-dictionary
0729-my-calendar-i
0739-daily-temperatures
0753-open-the-lock
0772-construct-quad-tree
0816-design-hashset
0817-design-hashmap
0822-unique-morse-code-words
0825-max-increase-to-keep-city-skyline
0835-linked-list-components
0852-friends-of-appropriate-ages
0859-design-circular-deque
0860-design-circular-queue
0861-flipping-an-image
0881-loud-and-rich
0891-score-after-flipping-matrix
0894-random-pick-with-blacklist
0898-transpose-matrix
0912-random-pick-with-weight
0914-random-point-in-non-overlapping-rectangles
0936-rle-iterator
1032-satisfiability-of-equality-equations
1036-rotting-oranges
1050-construct-binary-search-tree-from-preorder-traversal
1072-next-greater-node-in-linked-list
1073-number-of-enclaves
1171-shortest-path-in-binary-matrix
1207-delete-nodes-and-return-forest
1325-path-with-maximum-probability
1350-remove-sub-folders-from-the-filesystem
1380-number-of-closed-islands
1407-group-the-people-given-the-group-size-they-belong-to
1436-get-watched-videos-by-your-friends
1477-product-of-the-last-k-numbers
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1497-design-a-stack-with-increment-operation
1510-find-lucky-integer-in-an-array
1582-design-browser-history
1706-min-cost-to-connect-all-points
1753-path-with-minimum-effort
1995-finding-pairs-with-a-certain-sum
2038-nearest-exit-from-entrance-in-maze
2144-maximum-difference-between-increasing-elements
2151-the-time-when-the-network-becomes-idle
2175-count-nodes-with-the-highest-score
2189-maximum-path-quality-of-a-graph
2237-longest-palindrome-by-concatenating-two-letter-words
2306-create-binary-tree-from-descriptions
2320-find-all-k-distant-indices-in-an-array
2375-minimum-obstacle-removal-to-reach-corner
2445-reachable-nodes-with-restrictions
2525-count-number-of-distinct-integers-after-reverse-operations
2724-convert-an-array-into-a-2d-array-with-conditions
3194-find-words-containing-character
3235-minimum-cost-to-convert-string-i
3321-type-of-triangle
3501-delete-nodes-from-linked-list-present-in-array
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii
3748-sort-matrix-by-diagonals
3849-equal-sum-grid-partition-i
3863-power-grid-maintenance

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
0215-kth-largest-element-in-an-array
0240-search-a-2d-matrix-ii
0347-top-k-frequent-elements
0654-maximum-binary-tree
0772-construct-quad-tree
1285-balance-a-binary-search-tree

Sorting

0015-3sum
0018-4sum
0049-group-anagrams
0056-merge-intervals
0075-sort-colors
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0229-majority-element-ii
0242-valid-anagram
0268-missing-number
0274-h-index
0347-top-k-frequent-elements
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0389-find-the-difference
0414-third-maximum-number
0451-sort-characters-by-frequency
0455-assign-cookies
0561-array-partition
0594-longest-harmonious-subsequence
0692-top-k-frequent-words
0720-longest-word-in-dictionary
0852-friends-of-appropriate-ages
0894-random-pick-with-blacklist
1029-vertical-order-traversal-of-a-binary-tree
1427-all-elements-in-two-binary-search-trees
1436-get-watched-videos-by-your-friends
2646-kth-largest-sum-in-a-binary-tree
3321-type-of-triangle
3748-sort-matrix-by-diagonals

Heap (Priority Queue)

0023-merge-k-sorted-lists
0215-kth-largest-element-in-an-array
0347-top-k-frequent-elements
0451-sort-characters-by-frequency
0692-top-k-frequent-words
0744-network-delay-time
0803-cheapest-flights-within-k-stops
1325-path-with-maximum-probability
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1753-path-with-minimum-effort
2375-minimum-obstacle-removal-to-reach-corner
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii
3863-power-grid-maintenance

Quickselect

0215-kth-largest-element-in-an-array
0347-top-k-frequent-elements

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
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
0146-lru-cache
0160-intersection-of-two-linked-lists
0187-repeated-dna-sequences
0202-happy-number
0208-implement-trie-prefix-tree
0217-contains-duplicate
0229-majority-element-ii
0242-valid-anagram
0268-missing-number
0290-word-pattern
0299-bulls-and-cows
0347-top-k-frequent-elements
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0380-insert-delete-getrandom-o1
0381-insert-delete-getrandom-o1-duplicates-allowed
0383-ransom-note
0387-first-unique-character-in-a-string
0389-find-the-difference
0398-random-pick-index
0409-longest-palindrome
0423-reconstruct-original-digits-from-english
0442-find-all-duplicates-in-an-array
0448-find-all-numbers-disappeared-in-an-array
0451-sort-characters-by-frequency
0457-circular-array-loop
0508-most-frequent-subtree-sum
0535-encode-and-decode-tinyurl
0575-distribute-candies
0594-longest-harmonious-subsequence
0677-map-sum-pairs
0690-employee-importance
0692-top-k-frequent-words
0720-longest-word-in-dictionary
0753-open-the-lock
0782-jewels-and-stones
0816-design-hashset
0817-design-hashmap
0822-unique-morse-code-words
0835-linked-list-components
0893-all-nodes-distance-k-in-binary-tree
0894-random-pick-with-blacklist
0896-smallest-subtree-with-all-the-deepest-nodes
0913-random-flip-matrix
0931-maximum-frequency-stack
1029-vertical-order-traversal-of-a-binary-tree
1207-delete-nodes-and-return-forest
1218-lowest-common-ancestor-of-deepest-leaves
1387-find-elements-in-a-contaminated-binary-tree
1407-group-the-people-given-the-group-size-they-belong-to
1436-get-watched-videos-by-your-friends
1469-minimum-number-of-steps-to-make-two-strings-anagram
1510-find-lucky-integer-in-an-array
1512-design-underground-system
1722-throne-inheritance
1995-finding-pairs-with-a-certain-sum
2237-longest-palindrome-by-concatenating-two-letter-words
2293-minimum-number-of-steps-to-make-two-strings-anagram-ii
2306-create-binary-tree-from-descriptions
2445-reachable-nodes-with-restrictions
2455-node-with-highest-edge-score
2461-amount-of-time-for-binary-tree-to-be-infected
2525-count-number-of-distinct-integers-after-reverse-operations
2677-cousins-in-binary-tree-ii
2724-convert-an-array-into-a-2d-array-with-conditions
3501-delete-nodes-from-linked-list-present-in-array
3753-maximum-difference-between-even-and-odd-frequency-i
3863-power-grid-maintenance

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0020-valid-parentheses
0022-generate-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string
0043-multiply-strings
0049-group-anagrams
0058-length-of-last-word
0065-valid-number
0079-word-search
0127-word-ladder
0165-compare-version-numbers
0187-repeated-dna-sequences
0208-implement-trie-prefix-tree
0224-basic-calculator
0227-basic-calculator-ii
0242-valid-anagram
0290-word-pattern
0297-serialize-and-deserialize-binary-tree
0299-bulls-and-cows
0345-reverse-vowels-of-a-string
0383-ransom-note
0387-first-unique-character-in-a-string
0389-find-the-difference
0399-evaluate-division
0409-longest-palindrome
0423-reconstruct-original-digits-from-english
0443-string-compression
0449-serialize-and-deserialize-bst
0451-sort-characters-by-frequency
0481-magical-string
0535-encode-and-decode-tinyurl
0537-complex-number-multiplication
0557-reverse-words-in-a-string-iii
0606-construct-string-from-binary-tree
0649-dota2-senate
0657-robot-return-to-origin
0677-map-sum-pairs
0692-top-k-frequent-words
0720-longest-word-in-dictionary
0742-to-lower-case
0753-open-the-lock
0782-jewels-and-stones
0822-unique-morse-code-words
1030-smallest-string-starting-from-leaf
1032-satisfiability-of-equality-equations
1093-recover-a-tree-from-preorder-traversal
1302-delete-characters-to-make-fancy-string
1350-remove-sub-folders-from-the-filesystem
1469-minimum-number-of-steps-to-make-two-strings-anagram
1512-design-underground-system
2237-longest-palindrome-by-concatenating-two-letter-words
2260-divide-a-string-into-groups-of-size-k
2293-minimum-number-of-steps-to-make-two-strings-anagram-ii
3194-find-words-containing-character
3235-minimum-cost-to-convert-string-i
3379-score-of-a-string
3396-valid-word
3617-find-the-original-typed-string-i
3753-maximum-difference-between-even-and-odd-frequency-i

Counting

0229-majority-element-ii
0299-bulls-and-cows
0347-top-k-frequent-elements
0383-ransom-note
0387-first-unique-character-in-a-string
0451-sort-characters-by-frequency
0594-longest-harmonious-subsequence
0692-top-k-frequent-words
0936-rle-iterator
1469-minimum-number-of-steps-to-make-two-strings-anagram
1510-find-lucky-integer-in-an-array
2237-longest-palindrome-by-concatenating-two-letter-words
2293-minimum-number-of-steps-to-make-two-strings-anagram-ii
2525-count-number-of-distinct-integers-after-reverse-operations
3753-maximum-difference-between-even-and-odd-frequency-i

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
0222-count-complete-tree-nodes
0240-search-a-2d-matrix-ii
0268-missing-number
0275-h-index-ii
0278-first-bad-version
0287-find-the-duplicate-number
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0367-valid-perfect-square
0374-guess-number-higher-or-lower
0540-single-element-in-a-sorted-array
0729-my-calendar-i
0852-friends-of-appropriate-ages
0894-random-pick-with-blacklist
0912-random-pick-with-weight
0914-random-point-in-non-overlapping-rectangles
1753-path-with-minimum-effort

Two Pointers

0005-longest-palindromic-substring
0015-3sum
0018-4sum
0026-remove-duplicates-from-sorted-array
0028-find-the-index-of-the-first-occurrence-in-a-string
0061-rotate-list
0075-sort-colors
0080-remove-duplicates-from-sorted-array-ii
0082-remove-duplicates-from-sorted-list-ii
0086-partition-list
0141-linked-list-cycle
0142-linked-list-cycle-ii
0143-reorder-list
0160-intersection-of-two-linked-lists
0165-compare-version-numbers
0189-rotate-array
0202-happy-number
0234-palindrome-linked-list
0283-move-zeroes
0287-find-the-duplicate-number
0345-reverse-vowels-of-a-string
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0443-string-compression
0455-assign-cookies
0457-circular-array-loop
0481-magical-string
0528-swapping-nodes-in-a-linked-list
0557-reverse-words-in-a-string-iii
0852-friends-of-appropriate-ages
0861-flipping-an-image
2216-delete-the-middle-node-of-a-linked-list
2320-find-all-k-distant-indices-in-an-array

Bit Manipulation

0029-divide-two-integers
0136-single-number
0137-single-number-ii
0187-repeated-dna-sequences
0222-count-complete-tree-nodes
0231-power-of-two
0260-single-number-iii
0268-missing-number
0287-find-the-duplicate-number
0338-counting-bits
0371-sum-of-two-integers
0389-find-the-difference
0476-number-complement
0861-flipping-an-image
0891-score-after-flipping-matrix
3600-find-the-k-th-character-in-string-game-i

Math

0029-divide-two-integers
0043-multiply-strings
0048-rotate-image
0060-permutation-sequence
0069-sqrtx
0096-unique-binary-search-trees
0150-evaluate-reverse-polish-notation
0189-rotate-array
0202-happy-number
0204-count-primes
0223-rectangle-area
0224-basic-calculator
0227-basic-calculator-ii
0231-power-of-two
0268-missing-number
0292-nim-game
0357-count-numbers-with-unique-digits
0367-valid-perfect-square
0371-sum-of-two-integers
0380-insert-delete-getrandom-o1
0381-insert-delete-getrandom-o1-duplicates-allowed
0382-linked-list-random-node
0384-shuffle-an-array
0396-rotate-function
0398-random-pick-index
0423-reconstruct-original-digits-from-english
0445-add-two-numbers-ii
0537-complex-number-multiplication
0894-random-pick-with-blacklist
0903-implement-rand10-using-rand7
0912-random-pick-with-weight
0913-random-flip-matrix
0914-random-point-in-non-overlapping-rectangles
1013-fibonacci-number
1411-convert-binary-number-in-a-linked-list-to-integer
1448-maximum-69-number
1477-product-of-the-last-k-numbers
2525-count-number-of-distinct-integers-after-reverse-operations
2704-maximum-difference-by-remapping-a-digit
2871-double-a-number-represented-as-a-linked-list
2903-insert-greatest-common-divisors-in-linked-list
3172-divisible-and-non-divisible-sums-difference
3321-type-of-triangle
3600-find-the-k-th-character-in-string-game-i

Dynamic Programming

0005-longest-palindromic-substring
0022-generate-parentheses
0053-maximum-subarray
0095-unique-binary-search-trees-ii
0096-unique-binary-search-trees
0118-pascals-triangle
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0329-longest-increasing-path-in-a-matrix
0338-counting-bits
0357-count-numbers-with-unique-digits
0396-rotate-function
0413-arithmetic-slices
0803-cheapest-flights-within-k-stops
1013-fibonacci-number
1456-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance

Backtracking

0022-generate-parentheses
0046-permutations
0079-word-search
0095-unique-binary-search-trees-ii
0357-count-numbers-with-unique-digits
0813-all-paths-from-source-to-target
1030-smallest-string-starting-from-leaf
2189-maximum-path-quality-of-a-graph

Bucket Sort

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

Stack

0020-valid-parentheses
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
0173-binary-search-tree-iterator
0224-basic-calculator
0225-implement-stack-using-queues
0227-basic-calculator-ii
0234-palindrome-linked-list
0341-flatten-nested-list-iterator
0445-add-two-numbers-ii
0503-next-greater-element-ii
0654-maximum-binary-tree
0739-daily-temperatures
0931-maximum-frequency-stack
1050-construct-binary-search-tree-from-preorder-traversal
1072-next-greater-node-in-linked-list
1497-design-a-stack-with-increment-operation
1582-design-browser-history
2871-double-a-number-represented-as-a-linked-list

Monotonic Stack

0503-next-greater-element-ii
0654-maximum-binary-tree
0739-daily-temperatures
1050-construct-binary-search-tree-from-preorder-traversal
1072-next-greater-node-in-linked-list

Linked List

0021-merge-two-sorted-lists
0023-merge-k-sorted-lists
0024-swap-nodes-in-pairs
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
0117-populating-next-right-pointers-in-each-node-ii
0138-copy-list-with-random-pointer
0141-linked-list-cycle
0142-linked-list-cycle-ii
0143-reorder-list
0146-lru-cache
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
0382-linked-list-random-node
0445-add-two-numbers-ii
0528-swapping-nodes-in-a-linked-list
0725-split-linked-list-in-parts
0816-design-hashset
0817-design-hashmap
0835-linked-list-components
0838-design-linked-list
0859-design-circular-deque
0860-design-circular-queue
1072-next-greater-node-in-linked-list
1411-convert-binary-number-in-a-linked-list-to-integer
1484-linked-list-in-binary-tree
1582-design-browser-history
1765-merge-in-between-linked-lists
2216-delete-the-middle-node-of-a-linked-list
2299-merge-nodes-in-between-zeros
2871-double-a-number-represented-as-a-linked-list
2903-insert-greatest-common-divisors-in-linked-list
3501-delete-nodes-from-linked-list-present-in-array

Matrix

0048-rotate-image
0054-spiral-matrix
0059-spiral-matrix-ii
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0079-word-search
0130-surrounded-regions
0200-number-of-islands
0240-search-a-2d-matrix-ii
0289-game-of-life
0329-longest-increasing-path-in-a-matrix
0417-pacific-atlantic-water-flow
0419-battleships-in-a-board
0498-diagonal-traverse
0529-minesweeper
0566-reshape-the-matrix
0695-max-area-of-island
0772-construct-quad-tree
0825-max-increase-to-keep-city-skyline
0861-flipping-an-image
0891-score-after-flipping-matrix
0898-transpose-matrix
1036-rotting-oranges
1073-number-of-enclaves
1171-shortest-path-in-binary-matrix
1380-number-of-closed-islands
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1753-path-with-minimum-effort
2038-nearest-exit-from-entrance-in-maze
2375-minimum-obstacle-removal-to-reach-corner
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii
3748-sort-matrix-by-diagonals
3849-equal-sum-grid-partition-i

Recursion

0021-merge-two-sorted-lists
0024-swap-nodes-in-pairs
0060-permutation-sequence
0143-reorder-list
0203-remove-linked-list-elements
0206-reverse-linked-list
0224-basic-calculator
0231-power-of-two
0234-palindrome-linked-list
1013-fibonacci-number
3600-find-the-k-th-character-in-string-game-i

Memoization

0329-longest-increasing-path-in-a-matrix
1013-fibonacci-number

Merge Sort

0023-merge-k-sorted-lists

Simulation

0043-multiply-strings
0054-spiral-matrix
0059-spiral-matrix-ii
0289-game-of-life
0498-diagonal-traverse
0537-complex-number-multiplication
0566-reshape-the-matrix
0657-robot-return-to-origin
0861-flipping-an-image
0898-transpose-matrix
2260-divide-a-string-into-groups-of-size-k
2299-merge-nodes-in-between-zeros
3600-find-the-k-th-character-in-string-game-i

Enumeration

0204-count-primes
3849-equal-sum-grid-partition-i

Number Theory

0204-count-primes
2903-insert-greatest-common-divisors-in-linked-list

Counting Sort

0274-h-index
0561-array-partition

String Matching

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

Geometry

0223-rectangle-area

Queue

0225-implement-stack-using-queues
0341-flatten-nested-list-iterator
0387-first-unique-character-in-a-string
0649-dota2-senate
0859-design-circular-deque
0860-design-circular-queue

Greedy

0122-best-time-to-buy-and-sell-stock-ii
0409-longest-palindrome
0455-assign-cookies
0561-array-partition
0649-dota2-senate
0825-max-increase-to-keep-city-skyline
0891-score-after-flipping-matrix
1285-balance-a-binary-search-tree
1407-group-the-people-given-the-group-size-they-belong-to
1448-maximum-69-number
2237-longest-palindrome-by-concatenating-two-letter-words
2704-maximum-difference-by-remapping-a-digit

Prefix Sum

0238-product-of-array-except-self
0912-random-pick-with-weight
0914-random-point-in-non-overlapping-rectangles
1477-product-of-the-last-k-numbers
3271-count-the-number-of-houses-at-a-certain-distance-i
3849-equal-sum-grid-partition-i

Depth-First Search

0079-word-search
0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0099-recover-binary-search-tree
0100-same-tree
0104-maximum-depth-of-binary-tree
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
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
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0236-lowest-common-ancestor-of-a-binary-tree
0297-serialize-and-deserialize-binary-tree
0329-longest-increasing-path-in-a-matrix
0341-flatten-nested-list-iterator
0399-evaluate-division
0417-pacific-atlantic-water-flow
0419-battleships-in-a-board
0449-serialize-and-deserialize-bst
0508-most-frequent-subtree-sum
0513-find-bottom-left-tree-value
0515-find-largest-value-in-each-tree-row
0529-minesweeper
0538-convert-bst-to-greater-tree
0547-number-of-provinces
0606-construct-string-from-binary-tree
0623-add-one-row-to-tree
0655-print-binary-tree
0669-trim-a-binary-search-tree
0690-employee-importance
0695-max-area-of-island
0744-network-delay-time
0801-is-graph-bipartite
0803-cheapest-flights-within-k-stops
0813-all-paths-from-source-to-target
0820-find-eventual-safe-states
0832-binary-tree-pruning
0871-keys-and-rooms
0881-loud-and-rich
0893-all-nodes-distance-k-in-binary-tree
0896-smallest-subtree-with-all-the-deepest-nodes
0922-possible-bipartition
0988-flip-equivalent-binary-trees
1029-vertical-order-traversal-of-a-binary-tree
1030-smallest-string-starting-from-leaf
1073-number-of-enclaves
1092-maximum-difference-between-node-and-ancestor
1093-recover-a-tree-from-preorder-traversal
1114-binary-search-tree-to-greater-sum-tree
1116-maximum-level-sum-of-a-binary-tree
1120-flower-planting-with-no-adjacent
1207-delete-nodes-and-return-forest
1218-lowest-common-ancestor-of-deepest-leaves
1243-sum-of-nodes-with-even-valued-grandparent
1254-deepest-leaves-sum
1275-validate-binary-tree-nodes
1285-balance-a-binary-search-tree
1350-remove-sub-folders-from-the-filesystem
1380-number-of-closed-islands
1387-find-elements-in-a-contaminated-binary-tree
1427-all-elements-in-two-binary-search-trees
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1442-number-of-operations-to-make-network-connected
1450-delete-leaves-with-a-given-value
1484-linked-list-in-binary-tree
1492-time-needed-to-inform-all-employees
1544-count-good-nodes-in-binary-tree
1558-course-schedule-iv
1576-reorder-routes-to-make-all-paths-lead-to-the-city-zero
1722-throne-inheritance
1753-path-with-minimum-effort
2175-count-nodes-with-the-highest-score
2347-count-nodes-equal-to-average-of-subtree
2403-count-unreachable-pairs-of-nodes-in-an-undirected-graph
2438-find-closest-node-to-given-two-nodes
2445-reachable-nodes-with-restrictions
2461-amount-of-time-for-binary-tree-to-be-infected
2493-reverse-odd-levels-of-binary-tree
2582-minimum-score-of-a-path-between-two-cities
2677-cousins-in-binary-tree-ii
2793-count-the-number-of-complete-components
3729-unit-conversion-i
3863-power-grid-maintenance

Sliding Window

0003-longest-substring-without-repeating-characters
0187-repeated-dna-sequences
0413-arithmetic-slices
0594-longest-harmonious-subsequence

Design

0146-lru-cache
0155-min-stack
0173-binary-search-tree-iterator
0208-implement-trie-prefix-tree
0225-implement-stack-using-queues
0284-peeking-iterator
0297-serialize-and-deserialize-binary-tree
0341-flatten-nested-list-iterator
0380-insert-delete-getrandom-o1
0381-insert-delete-getrandom-o1-duplicates-allowed
0384-shuffle-an-array
0449-serialize-and-deserialize-bst
0535-encode-and-decode-tinyurl
0677-map-sum-pairs
0729-my-calendar-i
0816-design-hashset
0817-design-hashmap
0838-design-linked-list
0859-design-circular-deque
0860-design-circular-queue
0931-maximum-frequency-stack
0936-rle-iterator
0955-complete-binary-tree-inserter
1387-find-elements-in-a-contaminated-binary-tree
1477-product-of-the-last-k-numbers
1497-design-a-stack-with-increment-operation
1512-design-underground-system
1582-design-browser-history
1722-throne-inheritance
1995-finding-pairs-with-a-certain-sum

Randomized

0380-insert-delete-getrandom-o1
0381-insert-delete-getrandom-o1-duplicates-allowed
0382-linked-list-random-node
0384-shuffle-an-array
0398-random-pick-index
0894-random-pick-with-blacklist
0903-implement-rand10-using-rand7
0912-random-pick-with-weight
0913-random-flip-matrix
0914-random-point-in-non-overlapping-rectangles

Ordered Set

0729-my-calendar-i
0914-random-point-in-non-overlapping-rectangles
0931-maximum-frequency-stack
3863-power-grid-maintenance

Graph

0133-clone-graph
0207-course-schedule
0210-course-schedule-ii
0329-longest-increasing-path-in-a-matrix
0399-evaluate-division
0547-number-of-provinces
0744-network-delay-time
0801-is-graph-bipartite
0803-cheapest-flights-within-k-stops
0813-all-paths-from-source-to-target
0820-find-eventual-safe-states
0871-keys-and-rooms
0881-loud-and-rich
0922-possible-bipartition
1032-satisfiability-of-equality-equations
1120-flower-planting-with-no-adjacent
1229-shortest-path-with-alternating-colors
1275-validate-binary-tree-nodes
1325-path-with-maximum-probability
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1436-get-watched-videos-by-your-friends
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
1576-reorder-routes-to-make-all-paths-lead-to-the-city-zero
1661-minimum-number-of-vertices-to-reach-all-nodes
1706-min-cost-to-connect-all-points
1738-maximal-network-rank
1916-find-center-of-star-graph
2151-the-time-when-the-network-becomes-idle
2189-maximum-path-quality-of-a-graph
2375-minimum-obstacle-removal-to-reach-corner
2403-count-unreachable-pairs-of-nodes-in-an-undirected-graph
2438-find-closest-node-to-given-two-nodes
2445-reachable-nodes-with-restrictions
2455-node-with-highest-edge-score
2582-minimum-score-of-a-path-between-two-cities
2793-count-the-number-of-complete-components
3189-find-champion-ii
3235-minimum-cost-to-convert-string-i
3271-count-the-number-of-houses-at-a-certain-distance-i
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii
3729-unit-conversion-i
3863-power-grid-maintenance

Reservoir Sampling

0382-linked-list-random-node
0398-random-pick-index
0913-random-flip-matrix
0914-random-point-in-non-overlapping-rectangles

Interactive

0278-first-bad-version
0374-guess-number-higher-or-lower

Rejection Sampling

0903-implement-rand10-using-rand7

Probability and Statistics

0903-implement-rand10-using-rand7

Union Find

0128-longest-consecutive-sequence
0130-surrounded-regions
0200-number-of-islands
0399-evaluate-division
0547-number-of-provinces
0695-max-area-of-island
0801-is-graph-bipartite
0922-possible-bipartition
1032-satisfiability-of-equality-equations
1073-number-of-enclaves
1275-validate-binary-tree-nodes
1380-number-of-closed-islands
1442-number-of-operations-to-make-network-connected
1706-min-cost-to-connect-all-points
1753-path-with-minimum-effort
2403-count-unreachable-pairs-of-nodes-in-an-undirected-graph
2445-reachable-nodes-with-restrictions
2582-minimum-score-of-a-path-between-two-cities
2793-count-the-number-of-complete-components
3863-power-grid-maintenance

Hash Function

0187-repeated-dna-sequences
0535-encode-and-decode-tinyurl
0816-design-hashset
0817-design-hashmap

Rolling Hash

0187-repeated-dna-sequences

Iterator

0173-binary-search-tree-iterator
0284-peeking-iterator
0341-flatten-nested-list-iterator
0936-rle-iterator

Trie

0208-implement-trie-prefix-tree
0677-map-sum-pairs
0692-top-k-frequent-words
0720-longest-word-in-dictionary
1350-remove-sub-folders-from-the-filesystem

Segment Tree

0729-my-calendar-i

Brainteaser

0292-nim-game

Game Theory

0292-nim-game

Doubly-Linked List

0146-lru-cache
1582-design-browser-history

Tree

0094-binary-tree-inorder-traversal
0095-unique-binary-search-trees-ii
0096-unique-binary-search-trees
0098-validate-binary-search-tree
0099-recover-binary-search-tree
0100-same-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
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0129-sum-root-to-leaf-numbers
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0173-binary-search-tree-iterator
0199-binary-tree-right-side-view
0222-count-complete-tree-nodes
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0236-lowest-common-ancestor-of-a-binary-tree
0297-serialize-and-deserialize-binary-tree
0341-flatten-nested-list-iterator
0449-serialize-and-deserialize-bst
0450-delete-node-in-a-bst
0508-most-frequent-subtree-sum
0513-find-bottom-left-tree-value
0515-find-largest-value-in-each-tree-row
0538-convert-bst-to-greater-tree
0606-construct-string-from-binary-tree
0623-add-one-row-to-tree
0654-maximum-binary-tree
0655-print-binary-tree
0669-trim-a-binary-search-tree
0690-employee-importance
0764-n-ary-tree-level-order-traversal
0772-construct-quad-tree
0784-insert-into-a-binary-search-tree
0832-binary-tree-pruning
0893-all-nodes-distance-k-in-binary-tree
0896-smallest-subtree-with-all-the-deepest-nodes
0955-complete-binary-tree-inserter
0988-flip-equivalent-binary-trees
0998-check-completeness-of-a-binary-tree
1029-vertical-order-traversal-of-a-binary-tree
1030-smallest-string-starting-from-leaf
1040-maximum-binary-tree-ii
1050-construct-binary-search-tree-from-preorder-traversal
1092-maximum-difference-between-node-and-ancestor
1093-recover-a-tree-from-preorder-traversal
1114-binary-search-tree-to-greater-sum-tree
1116-maximum-level-sum-of-a-binary-tree
1207-delete-nodes-and-return-forest
1218-lowest-common-ancestor-of-deepest-leaves
1243-sum-of-nodes-with-even-valued-grandparent
1254-deepest-leaves-sum
1275-validate-binary-tree-nodes
1285-balance-a-binary-search-tree
1387-find-elements-in-a-contaminated-binary-tree
1427-all-elements-in-two-binary-search-trees
1450-delete-leaves-with-a-given-value
1484-linked-list-in-binary-tree
1492-time-needed-to-inform-all-employees
1544-count-good-nodes-in-binary-tree
1722-throne-inheritance
1731-even-odd-tree
2175-count-nodes-with-the-highest-score
2306-create-binary-tree-from-descriptions
2347-count-nodes-equal-to-average-of-subtree
2445-reachable-nodes-with-restrictions
2461-amount-of-time-for-binary-tree-to-be-infected
2493-reverse-odd-levels-of-binary-tree
2558-minimum-number-of-operations-to-sort-a-binary-tree-by-level
2646-kth-largest-sum-in-a-binary-tree
2677-cousins-in-binary-tree-ii

Binary Tree

0094-binary-tree-inorder-traversal
0095-unique-binary-search-trees-ii
0096-unique-binary-search-trees
0098-validate-binary-search-tree
0099-recover-binary-search-tree
0100-same-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
0114-flatten-binary-tree-to-linked-list
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0129-sum-root-to-leaf-numbers
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0173-binary-search-tree-iterator
0199-binary-tree-right-side-view
0222-count-complete-tree-nodes
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0236-lowest-common-ancestor-of-a-binary-tree
0297-serialize-and-deserialize-binary-tree
0449-serialize-and-deserialize-bst
0450-delete-node-in-a-bst
0508-most-frequent-subtree-sum
0513-find-bottom-left-tree-value
0515-find-largest-value-in-each-tree-row
0538-convert-bst-to-greater-tree
0606-construct-string-from-binary-tree
0623-add-one-row-to-tree
0654-maximum-binary-tree
0655-print-binary-tree
0669-trim-a-binary-search-tree
0784-insert-into-a-binary-search-tree
0832-binary-tree-pruning
0893-all-nodes-distance-k-in-binary-tree
0896-smallest-subtree-with-all-the-deepest-nodes
0955-complete-binary-tree-inserter
0988-flip-equivalent-binary-trees
0998-check-completeness-of-a-binary-tree
1029-vertical-order-traversal-of-a-binary-tree
1030-smallest-string-starting-from-leaf
1040-maximum-binary-tree-ii
1050-construct-binary-search-tree-from-preorder-traversal
1092-maximum-difference-between-node-and-ancestor
1093-recover-a-tree-from-preorder-traversal
1114-binary-search-tree-to-greater-sum-tree
1116-maximum-level-sum-of-a-binary-tree
1207-delete-nodes-and-return-forest
1218-lowest-common-ancestor-of-deepest-leaves
1243-sum-of-nodes-with-even-valued-grandparent
1254-deepest-leaves-sum
1275-validate-binary-tree-nodes
1285-balance-a-binary-search-tree
1387-find-elements-in-a-contaminated-binary-tree
1427-all-elements-in-two-binary-search-trees
1450-delete-leaves-with-a-given-value
1484-linked-list-in-binary-tree
1544-count-good-nodes-in-binary-tree
1731-even-odd-tree
2175-count-nodes-with-the-highest-score
2306-create-binary-tree-from-descriptions
2347-count-nodes-equal-to-average-of-subtree
2461-amount-of-time-for-binary-tree-to-be-infected
2493-reverse-odd-levels-of-binary-tree
2558-minimum-number-of-operations-to-sort-a-binary-tree-by-level
2646-kth-largest-sum-in-a-binary-tree
2677-cousins-in-binary-tree-ii

Breadth-First Search

0100-same-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
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
0297-serialize-and-deserialize-binary-tree
0329-longest-increasing-path-in-a-matrix
0399-evaluate-division
0417-pacific-atlantic-water-flow
0449-serialize-and-deserialize-bst
0513-find-bottom-left-tree-value
0515-find-largest-value-in-each-tree-row
0529-minesweeper
0547-number-of-provinces
0623-add-one-row-to-tree
0655-print-binary-tree
0690-employee-importance
0695-max-area-of-island
0744-network-delay-time
0753-open-the-lock
0764-n-ary-tree-level-order-traversal
0801-is-graph-bipartite
0803-cheapest-flights-within-k-stops
0813-all-paths-from-source-to-target
0820-find-eventual-safe-states
0871-keys-and-rooms
0893-all-nodes-distance-k-in-binary-tree
0896-smallest-subtree-with-all-the-deepest-nodes
0922-possible-bipartition
0955-complete-binary-tree-inserter
0998-check-completeness-of-a-binary-tree
1029-vertical-order-traversal-of-a-binary-tree
1036-rotting-oranges
1073-number-of-enclaves
1116-maximum-level-sum-of-a-binary-tree
1120-flower-planting-with-no-adjacent
1171-shortest-path-in-binary-matrix
1218-lowest-common-ancestor-of-deepest-leaves
1229-shortest-path-with-alternating-colors
1243-sum-of-nodes-with-even-valued-grandparent
1254-deepest-leaves-sum
1275-validate-binary-tree-nodes
1380-number-of-closed-islands
1387-find-elements-in-a-contaminated-binary-tree
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1436-get-watched-videos-by-your-friends
1442-number-of-operations-to-make-network-connected
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1492-time-needed-to-inform-all-employees
1544-count-good-nodes-in-binary-tree
1558-course-schedule-iv
1576-reorder-routes-to-make-all-paths-lead-to-the-city-zero
1731-even-odd-tree
1753-path-with-minimum-effort
2038-nearest-exit-from-entrance-in-maze
2151-the-time-when-the-network-becomes-idle
2375-minimum-obstacle-removal-to-reach-corner
2403-count-unreachable-pairs-of-nodes-in-an-undirected-graph
2445-reachable-nodes-with-restrictions
2461-amount-of-time-for-binary-tree-to-be-infected
2493-reverse-odd-levels-of-binary-tree
2558-minimum-number-of-operations-to-sort-a-binary-tree-by-level
2582-minimum-score-of-a-path-between-two-cities
2646-kth-largest-sum-in-a-binary-tree
2677-cousins-in-binary-tree-ii
2793-count-the-number-of-complete-components
3271-count-the-number-of-houses-at-a-certain-distance-i
3729-unit-conversion-i
3863-power-grid-maintenance

Binary Search Tree

0095-unique-binary-search-trees-ii
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
0173-binary-search-tree-iterator
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
0538-convert-bst-to-greater-tree
0669-trim-a-binary-search-tree
0784-insert-into-a-binary-search-tree
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

Data Stream

1477-product-of-the-last-k-numbers
1582-design-browser-history

Topological Sort

0207-course-schedule
0210-course-schedule-ii
0329-longest-increasing-path-in-a-matrix
0820-find-eventual-safe-states
0881-loud-and-rich
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1558-course-schedule-iv

Shortest Path

0399-evaluate-division
0744-network-delay-time
0803-cheapest-flights-within-k-stops
1325-path-with-maximum-probability
1456-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
2375-minimum-obstacle-removal-to-reach-corner
3235-minimum-cost-to-convert-string-i
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii

Minimum Spanning Tree

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