LeetCode

Collection of LeetCode questions to ace the coding interview! - Created using LeetHub

LeetCode Topics

Math

0048-rotate-image
0050-powx-n
0062-unique-paths
0070-climbing-stairs
0096-unique-binary-search-trees
0189-rotate-array
0204-count-primes
0231-power-of-two
0268-missing-number
0326-power-of-three
0368-largest-divisible-subset
1013-fibonacci-number
1236-n-th-tribonacci-number
1477-product-of-the-last-k-numbers
1500-count-largest-group
1529-max-difference-you-can-get-from-changing-an-integer
1889-check-if-number-is-a-sum-of-powers-of-three
1993-sum-of-all-subset-xor-totals
2050-count-good-numbers
2457-count-special-integers
2575-minimum-cuts-to-divide-a-circle
2610-closest-prime-numbers-in-range
2649-count-total-number-of-colored-cells
2704-maximum-difference-by-remapping-a-digit
2998-count-symmetric-integers
3172-divisible-and-non-divisible-sums-difference
3201-distribute-candies-among-children-ii
3227-find-missing-and-repeated-values
3243-count-the-number-of-powerful-integers
3321-type-of-triangle
3548-find-the-count-of-good-integers
3600-find-the-k-th-character-in-string-game-i
3601-find-the-k-th-character-in-string-game-ii
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-ii
3754-maximum-manhattan-distance-after-k-changes

Dynamic Programming

0005-longest-palindromic-substring
0045-jump-game-ii
0053-maximum-subarray
0055-jump-game
0062-unique-paths
0063-unique-paths-ii
0064-minimum-path-sum
0070-climbing-stairs
0095-unique-binary-search-trees-ii
0096-unique-binary-search-trees
0118-pascals-triangle
0119-pascals-triangle-ii
0120-triangle
0121-best-time-to-buy-and-sell-stock
0198-house-robber
0213-house-robber-ii
0300-longest-increasing-subsequence
0329-longest-increasing-path-in-a-matrix
0338-counting-bits
0368-largest-divisible-subset
0377-combination-sum-iv
0392-is-subsequence
0416-partition-equal-subset-sum
0747-min-cost-climbing-stairs
0806-domino-and-tromino-tiling
0868-push-dominoes
0943-sum-of-subarray-minimums
0967-minimum-falling-path-sum
1013-fibonacci-number
1236-n-th-tribonacci-number
1511-count-number-of-teams
1851-maximum-number-of-events-that-can-be-attended-ii
1986-largest-color-value-in-a-directed-graph
2067-maximum-number-of-points-with-cost
2078-maximum-compatibility-score-sum
2090-number-of-ways-to-arrive-at-destination
2108-minimize-the-difference-between-target-and-chosen-elements
2267-minimum-difference-in-sums-after-removal-of-elements
2395-longest-binary-subsequence-less-than-or-equal-to-k
2457-count-special-integers
3142-longest-unequal-adjacent-groups-subsequence-ii
3143-longest-unequal-adjacent-groups-subsequence-i
3243-count-the-number-of-powerful-integers
3307-find-the-maximum-sum-of-node-values
3345-find-the-sum-of-the-power-of-all-subsequences
3490-find-the-maximum-length-of-valid-subsequence-i
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-ii

Memoization

0070-climbing-stairs
0329-longest-increasing-path-in-a-matrix
1013-fibonacci-number
1236-n-th-tribonacci-number
1986-largest-color-value-in-a-directed-graph
2395-longest-binary-subsequence-less-than-or-equal-to-k

Recursion

0050-powx-n
0231-power-of-two
0326-power-of-three
1013-fibonacci-number
2050-count-good-numbers
3600-find-the-k-th-character-in-string-game-i
3601-find-the-k-th-character-in-string-game-ii

Array

0001-two-sum
0015-3sum
0018-4sum
0026-remove-duplicates-from-sorted-array
0031-next-permutation
0045-jump-game-ii
0048-rotate-image
0053-maximum-subarray
0055-jump-game
0056-merge-intervals
0063-unique-paths-ii
0064-minimum-path-sum
0073-set-matrix-zeroes
0075-sort-colors
0078-subsets
0079-word-search
0088-merge-sorted-array
0118-pascals-triangle
0119-pascals-triangle-ii
0120-triangle
0121-best-time-to-buy-and-sell-stock
0128-longest-consecutive-sequence
0130-surrounded-regions
0135-candy
0153-find-minimum-in-rotated-sorted-array
0169-majority-element
0189-rotate-array
0198-house-robber
0204-count-primes
0209-minimum-size-subarray-sum
0213-house-robber-ii
0229-majority-element-ii
0238-product-of-array-except-self
0268-missing-number
0283-move-zeroes
0300-longest-increasing-subsequence
0329-longest-increasing-path-in-a-matrix
0368-largest-divisible-subset
0373-find-k-pairs-with-smallest-sums
0377-combination-sum-iv
0407-trapping-rain-water-ii
0416-partition-equal-subset-sum
0496-next-greater-element-i
0560-subarray-sum-equals-k
0594-longest-harmonious-subsequence
0747-min-cost-climbing-stairs
0940-fruit-into-baskets
0943-sum-of-subarray-minimums
0945-snakes-and-ladders
0967-minimum-falling-path-sum
1049-minimum-domino-rotations-for-equal-row
1073-number-of-enclaves
1227-number-of-equivalent-domino-pairs
1293-three-consecutive-odds
1350-remove-sub-folders-from-the-filesystem
1424-maximum-candies-you-can-get-from-boxes
1477-product-of-the-last-k-numbers
1478-maximum-number-of-events-that-can-be-attended
1511-count-number-of-teams
1616-minimum-difference-between-largest-and-smallest-value-in-three-moves
1656-count-good-triplets
1813-maximum-erasure-value
1851-maximum-number-of-events-that-can-be-attended-ii
1993-sum-of-all-subset-xor-totals
2038-nearest-exit-from-entrance-in-maze
2048-build-array-from-permutation
2067-maximum-number-of-points-with-cost
2078-maximum-compatibility-score-sum
2108-minimize-the-difference-between-target-and-chosen-elements
2144-maximum-difference-between-increasing-elements
2150-kth-smallest-product-of-two-sorted-arrays
2180-maximum-number-of-tasks-you-can-assign
2215-finding-3-digit-even-numbers
2237-longest-palindrome-by-concatenating-two-letter-words
2249-count-the-hidden-sequences
2265-partition-array-according-to-given-pivot
2267-minimum-difference-in-sums-after-removal-of-elements
2271-rearrange-array-elements-by-sign
2277-count-equal-and-divisible-pairs-in-an-array
2316-count-hills-and-valleys-in-an-array
2320-find-all-k-distant-indices-in-an-array
2387-partition-array-such-that-maximum-difference-is-k
2498-smallest-subarrays-with-maximum-bitwise-or
2503-longest-subarray-with-maximum-bitwise-and
2591-frog-jump-ii
2614-maximum-count-of-positive-integer-and-negative-integer
2626-count-the-number-of-good-subarrays
2689-rearranging-fruits
2699-count-the-number-of-fair-pairs
2720-minimize-the-maximum-difference-of-pairs
2856-count-complete-subarrays-in-an-array
2915-count-of-interesting-subarrays
3142-longest-unequal-adjacent-groups-subsequence-ii
3143-longest-unequal-adjacent-groups-subsequence-i
3152-maximum-value-of-an-ordered-triplet-ii
3171-minimum-equal-sum-of-two-arrays-after-replacing-zeros
3194-find-words-containing-character
3213-count-subarrays-where-max-element-appears-at-least-k-times
3227-find-missing-and-repeated-values
3241-divide-array-into-arrays-with-max-difference
3307-find-the-maximum-sum-of-node-values
3321-type-of-triangle
3345-find-the-sum-of-the-power-of-all-subsequences
3483-alternating-groups-ii
3490-find-the-maximum-length-of-valid-subsequence-i
3621-minimum-operations-to-make-array-values-equal-to-k
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii
3639-zero-array-transformation-i
3643-zero-array-transformation-ii
3647-zero-array-transformation-iii
3656-minimum-number-of-operations-to-make-elements-in-array-distinct
3685-count-subarrays-of-length-three-with-a-condition
3747-maximum-difference-between-adjacent-elements-in-a-circular-array
3789-maximize-subarrays-after-removing-one-conflicting-pair

Design

1477-product-of-the-last-k-numbers

Data Stream

1477-product-of-the-last-k-numbers

Prefix Sum

0209-minimum-size-subarray-sum
0238-product-of-array-except-self
0560-subarray-sum-equals-k
1477-product-of-the-last-k-numbers
2249-count-the-hidden-sequences
2915-count-of-interesting-subarrays
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

String

0005-longest-palindromic-substring
0038-count-and-say
0076-minimum-window-substring
0079-word-search
0392-is-subsequence
0551-student-attendance-record-i
0696-count-binary-substrings
0868-push-dominoes
1058-lexicographically-smallest-equivalent-string
1302-delete-characters-to-make-fancy-string
1350-remove-sub-folders-from-the-filesystem
1371-minimum-remove-to-make-valid-parentheses
1460-number-of-substrings-containing-all-three-characters
1567-maximum-number-of-vowels-in-a-substring-of-given-length
1818-maximum-score-from-removing-substrings
1894-merge-strings-alternately
2140-longest-subsequence-repeated-k-times
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
2456-construct-smallest-number-from-di-string
2463-minimum-recolors-to-get-k-consecutive-black-blocks
2520-using-a-robot-to-print-the-lexicographically-smallest-string
3142-longest-unequal-adjacent-groups-subsequence-ii
3143-longest-unequal-adjacent-groups-subsequence-i
3194-find-words-containing-character
3243-count-the-number-of-powerful-integers
3360-minimum-deletions-to-make-string-k-special
3396-valid-word
3445-lexicographically-minimum-string-after-removing-stars
3569-count-of-substrings-containing-every-vowel-and-k-consonants-ii
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-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

Backtracking

0078-subsets
0079-word-search
0095-unique-binary-search-trees-ii
1993-sum-of-all-subset-xor-totals
2078-maximum-compatibility-score-sum
2140-longest-subsequence-repeated-k-times
2456-construct-smallest-number-from-di-string

Stack

0496-next-greater-element-i
0943-sum-of-subarray-minimums
1371-minimum-remove-to-make-valid-parentheses
1818-maximum-score-from-removing-substrings
2456-construct-smallest-number-from-di-string
2520-using-a-robot-to-print-the-lexicographically-smallest-string
3445-lexicographically-minimum-string-after-removing-stars

Greedy

0045-jump-game-ii
0055-jump-game
0135-candy
1049-minimum-domino-rotations-for-equal-row
1478-maximum-number-of-events-that-can-be-attended
1529-max-difference-you-can-get-from-changing-an-integer
1616-minimum-difference-between-largest-and-smallest-value-in-three-moves
1818-maximum-score-from-removing-substrings
2140-longest-subsequence-repeated-k-times
2180-maximum-number-of-tasks-you-can-assign
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
2520-using-a-robot-to-print-the-lexicographically-smallest-string
2591-frog-jump-ii
2689-rearranging-fruits
2704-maximum-difference-by-remapping-a-digit
2720-minimize-the-maximum-difference-of-pairs
3143-longest-unequal-adjacent-groups-subsequence-i
3171-minimum-equal-sum-of-two-arrays-after-replacing-zeros
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

Two Pointers

0005-longest-palindromic-substring
0015-3sum
0018-4sum
0026-remove-duplicates-from-sorted-array
0031-next-permutation
0075-sort-colors
0088-merge-sorted-array
0189-rotate-array
0283-move-zeroes
0392-is-subsequence
0696-count-binary-substrings
0868-push-dominoes
1894-merge-strings-alternately
2265-partition-array-according-to-given-pivot
2271-rearrange-array-elements-by-sign
2320-find-all-k-distant-indices-in-an-array
2699-count-the-number-of-fair-pairs
3683-find-the-lexicographically-largest-string-from-the-box-i

Simulation

2048-build-array-from-permutation
2260-divide-a-string-into-groups-of-size-k
2265-partition-array-according-to-given-pivot
2271-rearrange-array-elements-by-sign
3600-find-the-k-th-character-in-string-game-i

Hash Table

0001-two-sum
0073-set-matrix-zeroes
0076-minimum-window-substring
0128-longest-consecutive-sequence
0169-majority-element
0229-majority-element-ii
0268-missing-number
0496-next-greater-element-i
0560-subarray-sum-equals-k
0594-longest-harmonious-subsequence
0940-fruit-into-baskets
1218-lowest-common-ancestor-of-deepest-leaves
1227-number-of-equivalent-domino-pairs
1460-number-of-substrings-containing-all-three-characters
1500-count-largest-group
1813-maximum-erasure-value
1986-largest-color-value-in-a-directed-graph
2215-finding-3-digit-even-numbers
2237-longest-palindrome-by-concatenating-two-letter-words
2520-using-a-robot-to-print-the-lexicographically-smallest-string
2626-count-the-number-of-good-subarrays
2689-rearranging-fruits
2856-count-complete-subarrays-in-an-array
2915-count-of-interesting-subarrays
3227-find-missing-and-repeated-values
3360-minimum-deletions-to-make-string-k-special
3445-lexicographically-minimum-string-after-removing-stars
3548-find-the-count-of-good-integers
3569-count-of-substrings-containing-every-vowel-and-k-consonants-ii
3621-minimum-operations-to-make-array-values-equal-to-k
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-ii
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

Matrix

0048-rotate-image
0063-unique-paths-ii
0064-minimum-path-sum
0073-set-matrix-zeroes
0079-word-search
0130-surrounded-regions
0329-longest-increasing-path-in-a-matrix
0407-trapping-rain-water-ii
0945-snakes-and-ladders
0967-minimum-falling-path-sum
1073-number-of-enclaves
2038-nearest-exit-from-entrance-in-maze
2067-maximum-number-of-points-with-cost
2108-minimize-the-difference-between-target-and-chosen-elements
3227-find-missing-and-repeated-values
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii

Number Theory

0204-count-primes
2610-closest-prime-numbers-in-range

Geometry

2575-minimum-cuts-to-divide-a-circle

Sliding Window

0076-minimum-window-substring
0209-minimum-size-subarray-sum
0594-longest-harmonious-subsequence
0940-fruit-into-baskets
1460-number-of-substrings-containing-all-three-characters
1567-maximum-number-of-vowels-in-a-substring-of-given-length
1813-maximum-erasure-value
2463-minimum-recolors-to-get-k-consecutive-black-blocks
2498-smallest-subarrays-with-maximum-bitwise-or
2626-count-the-number-of-good-subarrays
2856-count-complete-subarrays-in-an-array
3213-count-subarrays-where-max-element-appears-at-least-k-times
3483-alternating-groups-ii
3569-count-of-substrings-containing-every-vowel-and-k-consonants-ii
3761-maximum-difference-between-even-and-odd-frequency-ii

Binary Search

0153-find-minimum-in-rotated-sorted-array
0209-minimum-size-subarray-sum
0268-missing-number
0300-longest-increasing-subsequence
1851-maximum-number-of-events-that-can-be-attended-ii
2150-kth-smallest-product-of-two-sorted-arrays
2180-maximum-number-of-tasks-you-can-assign
2498-smallest-subarrays-with-maximum-bitwise-or
2591-frog-jump-ii
2614-maximum-count-of-positive-integer-and-negative-integer
2699-count-the-number-of-fair-pairs
2720-minimize-the-maximum-difference-of-pairs
3643-zero-array-transformation-ii
3881-minimize-maximum-component-cost
3908-minimum-time-for-k-connected-components

Counting

0169-majority-element
0229-majority-element-ii
0594-longest-harmonious-subsequence
1227-number-of-equivalent-domino-pairs
1986-largest-color-value-in-a-directed-graph
2140-longest-subsequence-repeated-k-times
2237-longest-palindrome-by-concatenating-two-letter-words
2614-maximum-count-of-positive-integer-and-negative-integer
3360-minimum-deletions-to-make-string-k-special
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-ii
3753-maximum-difference-between-even-and-odd-frequency-i
3754-maximum-manhattan-distance-after-k-changes

Database

0175-combine-two-tables
0177-nth-highest-salary
0178-rank-scores
0180-consecutive-numbers
0182-duplicate-emails
0183-customers-who-never-order
0584-find-customer-referee
0595-big-countries

Bit Manipulation

0078-subsets
0231-power-of-two
0268-missing-number
0338-counting-bits
1993-sum-of-all-subset-xor-totals
2078-maximum-compatibility-score-sum
2498-smallest-subarrays-with-maximum-bitwise-or
2503-longest-subarray-with-maximum-bitwise-and
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

Combinatorics

0062-unique-paths
1993-sum-of-all-subset-xor-totals
3201-distribute-candies-among-children-ii
3548-find-the-count-of-good-integers

Enumeration

0204-count-primes
1656-count-good-triplets
1993-sum-of-all-subset-xor-totals
2140-longest-subsequence-repeated-k-times
2215-finding-3-digit-even-numbers
2998-count-symmetric-integers
3201-distribute-candies-among-children-ii
3548-find-the-count-of-good-integers
3683-find-the-lexicographically-largest-string-from-the-box-i
3761-maximum-difference-between-even-and-odd-frequency-ii
3789-maximize-subarrays-after-removing-one-conflicting-pair

Sorting

0015-3sum
0018-4sum
0056-merge-intervals
0075-sort-colors
0088-merge-sorted-array
0169-majority-element
0229-majority-element-ii
0268-missing-number
0368-largest-divisible-subset
0594-longest-harmonious-subsequence
1478-maximum-number-of-events-that-can-be-attended
1616-minimum-difference-between-largest-and-smallest-value-in-three-moves
1851-maximum-number-of-events-that-can-be-attended-ii
2180-maximum-number-of-tasks-you-can-assign
2215-finding-3-digit-even-numbers
2387-partition-array-such-that-maximum-difference-is-k
2689-rearranging-fruits
2699-count-the-number-of-fair-pairs
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
3647-zero-array-transformation-iii
3881-minimize-maximum-component-cost
3908-minimum-time-for-k-connected-components

Tree

0095-unique-binary-search-trees-ii
0096-unique-binary-search-trees
0100-same-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0107-binary-tree-level-order-traversal-ii
0116-populating-next-right-pointers-in-each-node
0543-diameter-of-binary-tree
1218-lowest-common-ancestor-of-deepest-leaves
3307-find-the-maximum-sum-of-node-values
3633-maximize-the-number-of-target-nodes-after-connecting-trees-i
3645-maximize-the-number-of-target-nodes-after-connecting-trees-ii

Depth-First Search

0079-word-search
0100-same-tree
0116-populating-next-right-pointers-in-each-node
0130-surrounded-regions
0207-course-schedule
0210-course-schedule-ii
0310-minimum-height-trees
0329-longest-increasing-path-in-a-matrix
0332-reconstruct-itinerary
0386-lexicographical-numbers
0543-diameter-of-binary-tree
0684-redundant-connection
0744-network-delay-time
0801-is-graph-bipartite
0820-find-eventual-safe-states
1073-number-of-enclaves
1218-lowest-common-ancestor-of-deepest-leaves
1350-remove-sub-folders-from-the-filesystem
1558-course-schedule-iv
2438-find-closest-node-to-given-two-nodes
3633-maximize-the-number-of-target-nodes-after-connecting-trees-i
3645-maximize-the-number-of-target-nodes-after-connecting-trees-ii

Breadth-First Search

0100-same-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0107-binary-tree-level-order-traversal-ii
0116-populating-next-right-pointers-in-each-node
0130-surrounded-regions
0207-course-schedule
0210-course-schedule-ii
0310-minimum-height-trees
0329-longest-increasing-path-in-a-matrix
0407-trapping-rain-water-ii
0684-redundant-connection
0744-network-delay-time
0801-is-graph-bipartite
0820-find-eventual-safe-states
0945-snakes-and-ladders
1073-number-of-enclaves
1218-lowest-common-ancestor-of-deepest-leaves
1424-maximum-candies-you-can-get-from-boxes
1558-course-schedule-iv
2038-nearest-exit-from-entrance-in-maze
3633-maximize-the-number-of-target-nodes-after-connecting-trees-i
3645-maximize-the-number-of-target-nodes-after-connecting-trees-ii

Binary Tree

0095-unique-binary-search-trees-ii
0096-unique-binary-search-trees
0100-same-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0107-binary-tree-level-order-traversal-ii
0116-populating-next-right-pointers-in-each-node
0543-diameter-of-binary-tree
1218-lowest-common-ancestor-of-deepest-leaves

Queue

2180-maximum-number-of-tasks-you-can-assign

Monotonic Queue

2180-maximum-number-of-tasks-you-can-assign

Graph

0207-course-schedule
0210-course-schedule-ii
0310-minimum-height-trees
0329-longest-increasing-path-in-a-matrix
0332-reconstruct-itinerary
0684-redundant-connection
0744-network-delay-time
0801-is-graph-bipartite
0820-find-eventual-safe-states
1424-maximum-candies-you-can-get-from-boxes
1558-course-schedule-iv
1986-largest-color-value-in-a-directed-graph
2090-number-of-ways-to-arrive-at-destination
2438-find-closest-node-to-given-two-nodes
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii
3881-minimize-maximum-component-cost
3908-minimum-time-for-k-connected-components

Heap (Priority Queue)

0373-find-k-pairs-with-smallest-sums
0407-trapping-rain-water-ii
0744-network-delay-time
1478-maximum-number-of-events-that-can-be-attended
2267-minimum-difference-in-sums-after-removal-of-elements
3445-lexicographically-minimum-string-after-removing-stars
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii
3647-zero-array-transformation-iii

Shortest Path

0744-network-delay-time
2090-number-of-ways-to-arrive-at-destination
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii

Bitmask

2078-maximum-compatibility-score-sum

Divide and Conquer

0053-maximum-subarray
0169-majority-element

Topological Sort

0207-course-schedule
0210-course-schedule-ii
0310-minimum-height-trees
0329-longest-increasing-path-in-a-matrix
0820-find-eventual-safe-states
1558-course-schedule-iv
1986-largest-color-value-in-a-directed-graph
2090-number-of-ways-to-arrive-at-destination

Linked List

0116-populating-next-right-pointers-in-each-node

Binary Search Tree

0095-unique-binary-search-trees-ii
0096-unique-binary-search-trees

Union Find

0128-longest-consecutive-sequence
0130-surrounded-regions
0684-redundant-connection
0801-is-graph-bipartite
1058-lexicographically-smallest-equivalent-string
1073-number-of-enclaves
3881-minimize-maximum-component-cost
3908-minimum-time-for-k-connected-components

Trie

0386-lexicographical-numbers
1350-remove-sub-folders-from-the-filesystem

Binary Indexed Tree

1511-count-number-of-teams

Segment Tree

1511-count-number-of-teams
3789-maximize-subarrays-after-removing-one-conflicting-pair

Eulerian Circuit

0332-reconstruct-itinerary

Monotonic Stack

0496-next-greater-element-i
0943-sum-of-subarray-minimums

Brainteaser

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