raju096

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

LeetCode Topics

Array

0015-3sum
0039-combination-sum
0041-first-missing-positive
0042-trapping-rain-water
0045-jump-game-ii
0047-permutations-ii
0049-group-anagrams
0053-maximum-subarray
0054-spiral-matrix
0055-jump-game
0059-spiral-matrix-ii
0063-unique-paths-ii
0075-sort-colors
0078-subsets
0079-word-search
0088-merge-sorted-array
0090-subsets-ii
0122-best-time-to-buy-and-sell-stock-ii
0130-surrounded-regions
0136-single-number
0137-single-number-ii
0139-word-break
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0179-largest-number
0200-number-of-islands
0209-minimum-size-subarray-sum
0215-kth-largest-element-in-an-array
0219-contains-duplicate-ii
0221-maximal-square
0229-majority-element-ii
0260-single-number-iii
0268-missing-number
0287-find-the-duplicate-number
0324-wiggle-sort-ii
0334-increasing-triplet-subsequence
0363-max-sum-of-rectangle-no-larger-than-k
0442-find-all-duplicates-in-an-array
0455-assign-cookies
0462-minimum-moves-to-equal-array-elements-ii
0486-predict-the-winner
0539-minimum-time-difference
0540-single-element-in-a-sorted-array
0560-subarray-sum-equals-k
0561-array-partition
0605-can-place-flowers
0632-smallest-range-covering-elements-from-k-lists
0643-maximum-average-subarray-i
0646-maximum-length-of-pair-chain
0658-find-k-closest-elements
0665-non-decreasing-array
0713-subarray-product-less-than-k
0729-my-calendar-i
0731-my-calendar-ii
0814-smallest-rotation-with-highest-score
0824-number-of-lines-to-write-string
0854-making-a-large-island
0876-hand-of-straights
0878-shifting-letters
0882-peak-index-in-a-mountain-array
0906-walking-robot-simulation
0909-stone-game
0940-fruit-into-baskets
0948-sort-an-array
0952-word-subsets
0966-binary-subarrays-with-sum
1002-maximum-width-ramp
1034-subarrays-with-k-different-integers
1036-rotting-oranges
1072-next-greater-node-in-linked-list
1184-car-pooling
1206-corporate-flight-bookings
1350-remove-sub-folders-from-the-filesystem
1364-tuple-with-same-product
1370-count-number-of-nice-subarrays
1392-find-the-difference-of-two-arrays
1407-group-the-people-given-the-group-size-they-belong-to
1435-xor-queries-of-a-subarray
1445-number-of-sub-arrays-of-size-k-and-average-greater-than-or-equal-to-threshold
1476-count-negative-numbers-in-a-sorted-matrix
1482-how-many-numbers-are-smaller-than-the-current-number
1524-string-matching-in-an-array
1556-make-two-arrays-equal-by-reversing-subarrays
1586-longest-subarray-of-1s-after-deleting-one-element
1615-range-sum-of-sorted-subarray-sums
1620-check-if-array-pairs-are-divisible-by-k
1635-number-of-good-pairs
1786-count-the-number-of-consistent-strings
1803-average-waiting-time
1878-check-if-array-is-sorted-and-rotated
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1927-maximum-ascending-subarray-sum
1945-finding-the-users-active-minutes
2026-merge-triplets-to-form-target-triplet
2035-count-sub-islands
2038-nearest-exit-from-entrance-in-maze
2058-concatenation-of-array
2077-largest-number-after-mutating-substring
2094-remove-stones-to-minimize-the-total
2129-number-of-pairs-of-interchangeable-rectangles
2145-grid-game
2148-minimum-number-of-moves-to-seat-everyone
2155-find-missing-observations
2170-count-number-of-maximum-bitwise-or-subsets
2229-maximum-fruits-harvested-after-at-most-k-steps
2244-number-of-laser-beams-in-a-bank
2245-destroying-asteroids
2265-partition-array-according-to-given-pivot
2292-counting-words-with-a-given-prefix
2310-minimum-operations-to-halve-array-sum
2338-minimum-consecutive-cards-to-pick-up
2375-minimum-obstacle-removal-to-reach-corner
2378-sender-with-largest-word-count
2465-shifting-letters-ii
2494-sum-of-prefix-scores-of-strings
2502-sort-the-people
2503-longest-subarray-with-maximum-bitwise-and
2543-most-popular-video-creator
2581-divide-players-into-teams-of-equal-skill
2586-longest-square-streak-in-an-array
2616-maximal-score-after-applying-k-operations
2655-rearrange-array-to-maximize-prefix-score
2691-count-vowel-strings-in-ranges
2724-convert-an-array-into-a-2d-array-with-conditions
2727-number-of-senior-citizens
2755-extra-characters-in-a-string
2766-find-the-prefix-common-array-of-two-arrays
2794-maximum-number-of-moves-in-a-grid
2917-count-pairs-whose-sum-is-less-than-target
3093-sum-of-values-at-indices-with-k-set-bits
3193-maximum-strong-pair-xor-i
3291-find-if-array-can-be-sorted
3309-count-prefix-and-suffix-pairs-i
3332-minimum-operations-to-exceed-threshold-value-ii
3427-special-array-ii
3428-find-the-xor-of-numbers-which-appear-twice
3429-special-array-i
3558-find-a-safe-walk-through-a-grid
3627-find-minimum-time-to-reach-last-room-i

Bit Manipulation

0078-subsets
0090-subsets-ii
0136-single-number
0137-single-number-ii
0187-repeated-dna-sequences
0231-power-of-two
0260-single-number-iii
0268-missing-number
0287-find-the-duplicate-number
0342-power-of-four
0371-sum-of-two-integers
0389-find-the-difference
0397-integer-replacement
0461-hamming-distance
0693-binary-number-with-alternating-bits
1054-complement-of-base-10-integer
1435-xor-queries-of-a-subarray
1444-number-of-steps-to-reduce-a-number-to-zero
1786-count-the-number-of-consistent-strings
2059-unique-length-3-palindromic-subsequences
2170-count-number-of-maximum-bitwise-or-subsets
2503-longest-subarray-with-maximum-bitwise-and
2766-find-the-prefix-common-array-of-two-arrays
3093-sum-of-values-at-indices-with-k-set-bits
3193-maximum-strong-pair-xor-i
3291-find-if-array-can-be-sorted
3428-find-the-xor-of-numbers-which-appear-twice

Database

0183-customers-who-never-order
0595-big-countries
0596-classes-more-than-5-students

Greedy

0045-jump-game-ii
0055-jump-game
0122-best-time-to-buy-and-sell-stock-ii
0179-largest-number
0316-remove-duplicate-letters
0324-wiggle-sort-ii
0334-increasing-triplet-subsequence
0397-integer-replacement
0409-longest-palindrome
0455-assign-cookies
0561-array-partition
0605-can-place-flowers
0632-smallest-range-covering-elements-from-k-lists
0646-maximum-length-of-pair-chain
0670-maximum-swap
0778-reorganize-string
0876-hand-of-straights
1303-minimum-moves-to-reach-target-score
1304-longest-happy-string
1502-construct-k-palindrome-strings
1770-minimum-deletions-to-make-character-frequencies-unique
1782-smallest-string-with-a-given-numeric-value
1879-maximum-score-from-removing-stones
2026-merge-triplets-to-form-target-triplet
2077-largest-number-after-mutating-substring
2094-remove-stones-to-minimize-the-total
2148-minimum-number-of-moves-to-seat-everyone
2245-destroying-asteroids
2310-minimum-operations-to-halve-array-sum
2572-append-characters-to-string-to-make-subsequence
2616-maximal-score-after-applying-k-operations
2655-rearrange-array-to-maximize-prefix-score
3195-separate-black-and-white-balls

Sorting

0015-3sum
0049-group-anagrams
0075-sort-colors
0088-merge-sorted-array
0179-largest-number
0215-kth-largest-element-in-an-array
0229-majority-element-ii
0242-valid-anagram
0268-missing-number
0324-wiggle-sort-ii
0389-find-the-difference
0451-sort-characters-by-frequency
0455-assign-cookies
0462-minimum-moves-to-equal-array-elements-ii
0539-minimum-time-difference
0561-array-partition
0632-smallest-range-covering-elements-from-k-lists
0646-maximum-length-of-pair-chain
0658-find-k-closest-elements
0778-reorganize-string
0807-custom-sort-string
0876-hand-of-straights
0948-sort-an-array
1184-car-pooling
1482-how-many-numbers-are-smaller-than-the-current-number
1556-make-two-arrays-equal-by-reversing-subarrays
1615-range-sum-of-sorted-subarray-sums
1770-minimum-deletions-to-make-character-frequencies-unique
2148-minimum-number-of-moves-to-seat-everyone
2245-destroying-asteroids
2502-sort-the-people
2543-most-popular-video-creator
2581-divide-players-into-teams-of-equal-skill
2586-longest-square-streak-in-an-array
2655-rearrange-array-to-maximize-prefix-score
2917-count-pairs-whose-sum-is-less-than-target
3291-find-if-array-can-be-sorted

Backtracking

0017-letter-combinations-of-a-phone-number
0039-combination-sum
0047-permutations-ii
0077-combinations
0078-subsets
0079-word-search
0090-subsets-ii
0113-path-sum-ii
0126-word-ladder-ii
0357-count-numbers-with-unique-digits
2170-count-number-of-maximum-bitwise-or-subsets

Math

0012-integer-to-roman
0050-powx-n
0070-climbing-stairs
0231-power-of-two
0241-different-ways-to-add-parentheses
0268-missing-number
0326-power-of-three
0342-power-of-four
0357-count-numbers-with-unique-digits
0371-sum-of-two-integers
0390-elimination-game
0445-add-two-numbers-ii
0462-minimum-moves-to-equal-array-elements-ii
0486-predict-the-winner
0539-minimum-time-difference
0564-find-the-closest-palindrome
0592-fraction-addition-and-subtraction
0633-sum-of-square-numbers
0670-maximum-swap
0909-stone-game
1013-fibonacci-number
1303-minimum-moves-to-reach-target-score
1370-count-number-of-nice-subarrays
1444-number-of-steps-to-reduce-a-number-to-zero
1585-the-kth-factor-of-n
1635-number-of-good-pairs
1879-maximum-score-from-removing-stones
2129-number-of-pairs-of-interchangeable-rectangles
2155-find-missing-observations
2244-number-of-laser-beams-in-a-bank
2288-count-operations-to-obtain-zero

Recursion

0050-powx-n
0231-power-of-two
0241-different-ways-to-add-parentheses
0326-power-of-three
0342-power-of-four
0390-elimination-game
0486-predict-the-winner
1013-fibonacci-number

Matrix

0054-spiral-matrix
0059-spiral-matrix-ii
0063-unique-paths-ii
0079-word-search
0130-surrounded-regions
0200-number-of-islands
0221-maximal-square
0363-max-sum-of-rectangle-no-larger-than-k
0854-making-a-large-island
1036-rotting-oranges
1476-count-negative-numbers-in-a-sorted-matrix
2035-count-sub-islands
2038-nearest-exit-from-entrance-in-maze
2145-grid-game
2244-number-of-laser-beams-in-a-bank
2375-minimum-obstacle-removal-to-reach-corner
2794-maximum-number-of-moves-in-a-grid
3558-find-a-safe-walk-through-a-grid
3627-find-minimum-time-to-reach-last-room-i

Simulation

0054-spiral-matrix
0059-spiral-matrix-ii
0592-fraction-addition-and-subtraction
0906-walking-robot-simulation
1184-car-pooling
1803-average-waiting-time
2058-concatenation-of-array
2076-sum-of-digits-of-string-after-convert
2155-find-missing-observations
2265-partition-array-according-to-given-pivot
2288-count-operations-to-obtain-zero
2299-merge-nodes-in-between-zeros
2800-minimum-string-length-after-removing-substrings
3332-minimum-operations-to-exceed-threshold-value-ii

Dynamic Programming

0042-trapping-rain-water
0045-jump-game-ii
0053-maximum-subarray
0055-jump-game
0063-unique-paths-ii
0070-climbing-stairs
0122-best-time-to-buy-and-sell-stock-ii
0139-word-break
0221-maximal-square
0241-different-ways-to-add-parentheses
0357-count-numbers-with-unique-digits
0397-integer-replacement
0486-predict-the-winner
0646-maximum-length-of-pair-chain
0664-strange-printer
0909-stone-game
1013-fibonacci-number
1586-longest-subarray-of-1s-after-deleting-one-element
2586-longest-square-streak-in-an-array
2755-extra-characters-in-a-string
2794-maximum-number-of-moves-in-a-grid

Memoization

0070-climbing-stairs
0139-word-break
0241-different-ways-to-add-parentheses
0397-integer-replacement
1013-fibonacci-number

Two Pointers

0015-3sum
0042-trapping-rain-water
0075-sort-colors
0088-merge-sorted-array
0151-reverse-words-in-a-string
0167-two-sum-ii-input-array-is-sorted
0287-find-the-duplicate-number
0443-string-compression
0455-assign-cookies
0567-permutation-in-string
0633-sum-of-square-numbers
0658-find-k-closest-elements
1615-range-sum-of-sorted-subarray-sums
2265-partition-array-according-to-given-pivot
2572-append-characters-to-string-to-make-subsequence
2581-divide-players-into-teams-of-equal-skill
2917-count-pairs-whose-sum-is-less-than-target
3195-separate-black-and-white-balls

String

0003-longest-substring-without-repeating-characters
0012-integer-to-roman
0017-letter-combinations-of-a-phone-number
0049-group-anagrams
0079-word-search
0126-word-ladder-ii
0127-word-ladder
0139-word-break
0151-reverse-words-in-a-string
0179-largest-number
0187-repeated-dna-sequences
0214-shortest-palindrome
0241-different-ways-to-add-parentheses
0242-valid-anagram
0290-word-pattern
0316-remove-duplicate-letters
0383-ransom-note
0389-find-the-difference
0409-longest-palindrome
0443-string-compression
0451-sort-characters-by-frequency
0535-encode-and-decode-tinyurl
0539-minimum-time-difference
0564-find-the-closest-palindrome
0567-permutation-in-string
0592-fraction-addition-and-subtraction
0664-strange-printer
0778-reorganize-string
0782-jewels-and-stones
0807-custom-sort-string
0824-number-of-lines-to-write-string
0878-shifting-letters
0920-uncommon-words-from-two-sentences
0952-word-subsets
1304-longest-happy-string
1350-remove-sub-folders-from-the-filesystem
1502-construct-k-palindrome-strings
1524-string-matching-in-an-array
1537-maximum-score-after-splitting-a-string
1567-maximum-number-of-vowels-in-a-substring-of-given-length
1770-minimum-deletions-to-make-character-frequencies-unique
1782-smallest-string-with-a-given-numeric-value
1786-count-the-number-of-consistent-strings
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1915-check-if-one-string-swap-can-make-strings-equal
2053-check-if-all-characters-have-equal-number-of-occurrences
2059-unique-length-3-palindromic-subsequences
2076-sum-of-digits-of-string-after-convert
2077-largest-number-after-mutating-substring
2244-number-of-laser-beams-in-a-bank
2292-counting-words-with-a-given-prefix
2378-sender-with-largest-word-count
2465-shifting-letters-ii
2492-length-of-the-longest-alphabetical-continuous-substring
2494-sum-of-prefix-scores-of-strings
2502-sort-the-people
2543-most-popular-video-creator
2572-append-characters-to-string-to-make-subsequence
2691-count-vowel-strings-in-ranges
2727-number-of-senior-citizens
2755-extra-characters-in-a-string
2800-minimum-string-length-after-removing-substrings
3174-minimum-number-of-changes-to-make-binary-string-beautiful
3195-separate-black-and-white-balls
3309-count-prefix-and-suffix-pairs-i
3412-permutation-difference-between-two-strings
3451-string-compression-iii

Game Theory

0486-predict-the-winner
0909-stone-game

Hash Table

0003-longest-substring-without-repeating-characters
0012-integer-to-roman
0017-letter-combinations-of-a-phone-number
0041-first-missing-positive
0049-group-anagrams
0126-word-ladder-ii
0127-word-ladder
0139-word-break
0187-repeated-dna-sequences
0219-contains-duplicate-ii
0229-majority-element-ii
0242-valid-anagram
0268-missing-number
0290-word-pattern
0383-ransom-note
0389-find-the-difference
0409-longest-palindrome
0442-find-all-duplicates-in-an-array
0451-sort-characters-by-frequency
0535-encode-and-decode-tinyurl
0560-subarray-sum-equals-k
0567-permutation-in-string
0632-smallest-range-covering-elements-from-k-lists
0778-reorganize-string
0782-jewels-and-stones
0807-custom-sort-string
0876-hand-of-straights
0906-walking-robot-simulation
0920-uncommon-words-from-two-sentences
0940-fruit-into-baskets
0952-word-subsets
0966-binary-subarrays-with-sum
1034-subarrays-with-k-different-integers
1364-tuple-with-same-product
1370-count-number-of-nice-subarrays
1392-find-the-difference-of-two-arrays
1407-group-the-people-given-the-group-size-they-belong-to
1482-how-many-numbers-are-smaller-than-the-current-number
1502-construct-k-palindrome-strings
1556-make-two-arrays-equal-by-reversing-subarrays
1620-check-if-array-pairs-are-divisible-by-k
1635-number-of-good-pairs
1770-minimum-deletions-to-make-character-frequencies-unique
1786-count-the-number-of-consistent-strings
1915-check-if-one-string-swap-can-make-strings-equal
1945-finding-the-users-active-minutes
2053-check-if-all-characters-have-equal-number-of-occurrences
2059-unique-length-3-palindromic-subsequences
2129-number-of-pairs-of-interchangeable-rectangles
2338-minimum-consecutive-cards-to-pick-up
2378-sender-with-largest-word-count
2502-sort-the-people
2543-most-popular-video-creator
2581-divide-players-into-teams-of-equal-skill
2586-longest-square-streak-in-an-array
2677-cousins-in-binary-tree-ii
2724-convert-an-array-into-a-2d-array-with-conditions
2755-extra-characters-in-a-string
2766-find-the-prefix-common-array-of-two-arrays
3193-maximum-strong-pair-xor-i
3412-permutation-difference-between-two-strings
3428-find-the-xor-of-numbers-which-appear-twice

Binary Search

0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0209-minimum-size-subarray-sum
0268-missing-number
0287-find-the-duplicate-number
0363-max-sum-of-rectangle-no-larger-than-k
0540-single-element-in-a-sorted-array
0633-sum-of-square-numbers
0658-find-k-closest-elements
0729-my-calendar-i
0731-my-calendar-ii
0882-peak-index-in-a-mountain-array
1476-count-negative-numbers-in-a-sorted-matrix
1615-range-sum-of-sorted-subarray-sums
2229-maximum-fruits-harvested-after-at-most-k-steps
2586-longest-square-streak-in-an-array
2917-count-pairs-whose-sum-is-less-than-target
3427-special-array-ii

Sliding Window

0003-longest-substring-without-repeating-characters
0187-repeated-dna-sequences
0209-minimum-size-subarray-sum
0219-contains-duplicate-ii
0567-permutation-in-string
0632-smallest-range-covering-elements-from-k-lists
0643-maximum-average-subarray-i
0658-find-k-closest-elements
0713-subarray-product-less-than-k
0940-fruit-into-baskets
0966-binary-subarrays-with-sum
1034-subarrays-with-k-different-integers
1370-count-number-of-nice-subarrays
1445-number-of-sub-arrays-of-size-k-and-average-greater-than-or-equal-to-threshold
1567-maximum-number-of-vowels-in-a-substring-of-given-length
1586-longest-subarray-of-1s-after-deleting-one-element
2229-maximum-fruits-harvested-after-at-most-k-steps
2338-minimum-consecutive-cards-to-pick-up
3193-maximum-strong-pair-xor-i

Counting

0229-majority-element-ii
0383-ransom-note
0451-sort-characters-by-frequency
0778-reorganize-string
0920-uncommon-words-from-two-sentences
1034-subarrays-with-k-different-integers
1364-tuple-with-same-product
1482-how-many-numbers-are-smaller-than-the-current-number
1502-construct-k-palindrome-strings
1620-check-if-array-pairs-are-divisible-by-k
1635-number-of-good-pairs
1786-count-the-number-of-consistent-strings
1915-check-if-one-string-swap-can-make-strings-equal
2053-check-if-all-characters-have-equal-number-of-occurrences
2129-number-of-pairs-of-interchangeable-rectangles
2378-sender-with-largest-word-count
2494-sum-of-prefix-scores-of-strings

Design

0535-encode-and-decode-tinyurl
0729-my-calendar-i
0731-my-calendar-ii

Hash Function

0187-repeated-dna-sequences
0214-shortest-palindrome
0535-encode-and-decode-tinyurl
3309-count-prefix-and-suffix-pairs-i

Stack

0042-trapping-rain-water
0094-binary-tree-inorder-traversal
0144-binary-tree-preorder-traversal
0316-remove-duplicate-letters
0445-add-two-numbers-ii
0776-n-ary-tree-postorder-traversal
1002-maximum-width-ramp
1072-next-greater-node-in-linked-list
2800-minimum-string-length-after-removing-substrings

Tree

0094-binary-tree-inorder-traversal
0113-path-sum-ii
0129-sum-root-to-leaf-numbers
0144-binary-tree-preorder-traversal
0513-find-bottom-left-tree-value
0515-find-largest-value-in-each-tree-row
0776-n-ary-tree-postorder-traversal
0988-flip-equivalent-binary-trees
1484-linked-list-in-binary-tree
2677-cousins-in-binary-tree-ii

Depth-First Search

0094-binary-tree-inorder-traversal
0113-path-sum-ii
0129-sum-root-to-leaf-numbers
0130-surrounded-regions
0144-binary-tree-preorder-traversal
0200-number-of-islands
0207-course-schedule
0386-lexicographical-numbers
0513-find-bottom-left-tree-value
0515-find-largest-value-in-each-tree-row
0684-redundant-connection
0776-n-ary-tree-postorder-traversal
0820-find-eventual-safe-states
0854-making-a-large-island
0988-flip-equivalent-binary-trees
1300-critical-connections-in-a-network
1350-remove-sub-folders-from-the-filesystem
1484-linked-list-in-binary-tree
2035-count-sub-islands
2439-longest-cycle-in-a-graph
2677-cousins-in-binary-tree-ii
2793-count-the-number-of-complete-components

Trie

0139-word-break
0386-lexicographical-numbers
1350-remove-sub-folders-from-the-filesystem
2494-sum-of-prefix-scores-of-strings
2755-extra-characters-in-a-string
3193-maximum-strong-pair-xor-i
3309-count-prefix-and-suffix-pairs-i

Prefix Sum

0209-minimum-size-subarray-sum
0363-max-sum-of-rectangle-no-larger-than-k
0560-subarray-sum-equals-k
0731-my-calendar-ii
0814-smallest-rotation-with-highest-score
0878-shifting-letters
0966-binary-subarrays-with-sum
1184-car-pooling
1206-corporate-flight-bookings
1435-xor-queries-of-a-subarray
1537-maximum-score-after-splitting-a-string
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
2059-unique-length-3-palindromic-subsequences
2145-grid-game
2229-maximum-fruits-harvested-after-at-most-k-steps
2465-shifting-letters-ii
2655-rearrange-array-to-maximize-prefix-score
2691-count-vowel-strings-in-ranges
3427-special-array-ii

Heap (Priority Queue)

0023-merge-k-sorted-lists
0215-kth-largest-element-in-an-array
0451-sort-characters-by-frequency
0632-smallest-range-covering-elements-from-k-lists
0658-find-k-closest-elements
0778-reorganize-string
0948-sort-an-array
1184-car-pooling
1304-longest-happy-string
1879-maximum-score-from-removing-stones
2094-remove-stones-to-minimize-the-total
2310-minimum-operations-to-halve-array-sum
2375-minimum-obstacle-removal-to-reach-corner
2543-most-popular-video-creator
2616-maximal-score-after-applying-k-operations
3332-minimum-operations-to-exceed-threshold-value-ii
3558-find-a-safe-walk-through-a-grid
3627-find-minimum-time-to-reach-last-room-i

Breadth-First Search

0126-word-ladder-ii
0127-word-ladder
0130-surrounded-regions
0200-number-of-islands
0207-course-schedule
0513-find-bottom-left-tree-value
0515-find-largest-value-in-each-tree-row
0684-redundant-connection
0820-find-eventual-safe-states
0854-making-a-large-island
1036-rotting-oranges
1484-linked-list-in-binary-tree
2035-count-sub-islands
2038-nearest-exit-from-entrance-in-maze
2375-minimum-obstacle-removal-to-reach-corner
2671-shortest-cycle-in-a-graph
2677-cousins-in-binary-tree-ii
2793-count-the-number-of-complete-components
3558-find-a-safe-walk-through-a-grid

Union Find

0130-surrounded-regions
0200-number-of-islands
0684-redundant-connection
0854-making-a-large-island
2035-count-sub-islands
2793-count-the-number-of-complete-components

Monotonic Stack

0042-trapping-rain-water
0316-remove-duplicate-letters
1002-maximum-width-ramp
1072-next-greater-node-in-linked-list

Linked List

0023-merge-k-sorted-lists
0237-delete-node-in-a-linked-list
0445-add-two-numbers-ii
1072-next-greater-node-in-linked-list
1484-linked-list-in-binary-tree
2299-merge-nodes-in-between-zeros

Binary Tree

0094-binary-tree-inorder-traversal
0113-path-sum-ii
0129-sum-root-to-leaf-numbers
0144-binary-tree-preorder-traversal
0513-find-bottom-left-tree-value
0515-find-largest-value-in-each-tree-row
0988-flip-equivalent-binary-trees
1484-linked-list-in-binary-tree
2677-cousins-in-binary-tree-ii

Brainteaser

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

Bucket Sort

0451-sort-characters-by-frequency
0948-sort-an-array

Rolling Hash

0187-repeated-dna-sequences
0214-shortest-palindrome
3309-count-prefix-and-suffix-pairs-i

String Matching

0214-shortest-palindrome
1524-string-matching-in-an-array
2292-counting-words-with-a-given-prefix
3309-count-prefix-and-suffix-pairs-i

Graph

0207-course-schedule
0684-redundant-connection
0820-find-eventual-safe-states
1300-critical-connections-in-a-network
1916-find-center-of-star-graph
2375-minimum-obstacle-removal-to-reach-corner
2439-longest-cycle-in-a-graph
2671-shortest-cycle-in-a-graph
2793-count-the-number-of-complete-components
3558-find-a-safe-walk-through-a-grid
3627-find-minimum-time-to-reach-last-room-i

Divide and Conquer

0023-merge-k-sorted-lists
0053-maximum-subarray
0215-kth-largest-element-in-an-array
0324-wiggle-sort-ii
0948-sort-an-array

Quickselect

0215-kth-largest-element-in-an-array
0324-wiggle-sort-ii

Segment Tree

0729-my-calendar-i
0731-my-calendar-ii

Ordered Set

0363-max-sum-of-rectangle-no-larger-than-k
0729-my-calendar-i
0731-my-calendar-ii

Counting Sort

0561-array-partition
0948-sort-an-array

Merge Sort

0023-merge-k-sorted-lists
0948-sort-an-array

Radix Sort

0948-sort-an-array

Enumeration

2170-count-number-of-maximum-bitwise-or-subsets

Number Theory

1585-the-kth-factor-of-n
2129-number-of-pairs-of-interchangeable-rectangles

Biconnected Component

1300-critical-connections-in-a-network

Topological Sort

0207-course-schedule
0820-find-eventual-safe-states
2439-longest-cycle-in-a-graph

Shortest Path

2375-minimum-obstacle-removal-to-reach-corner
3558-find-a-safe-walk-through-a-grid
3627-find-minimum-time-to-reach-last-room-i