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
0031-next-permutation
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0039-combination-sum
0040-combination-sum-ii
0048-rotate-image
0053-maximum-subarray
0054-spiral-matrix
0063-unique-paths-ii
0064-minimum-path-sum
0074-search-a-2d-matrix
0075-sort-colors
0078-subsets
0081-search-in-rotated-sorted-array-ii
0090-subsets-ii
0120-triangle
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0123-best-time-to-buy-and-sell-stock-iii
0128-longest-consecutive-sequence
0130-surrounded-regions
0152-maximum-product-subarray
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0169-majority-element
0188-best-time-to-buy-and-sell-stock-iv
0189-rotate-array
0198-house-robber
0200-number-of-islands
0213-house-robber-ii
0215-kth-largest-element-in-an-array
0216-combination-sum-iii
0240-search-a-2d-matrix-ii
0300-longest-increasing-subsequence
0309-best-time-to-buy-and-sell-stock-with-cooldown
0312-burst-balloons
0322-coin-change
0354-russian-doll-envelopes
0368-largest-divisible-subset
0410-split-array-largest-sum
0416-partition-equal-subset-sum
0455-assign-cookies
0494-target-sum
0518-coin-change-ii
0523-continuous-subarray-sum
0540-single-element-in-a-sorted-array
0542-01-matrix
0560-subarray-sum-equals-k
0621-task-scheduler
0673-number-of-longest-increasing-subsequence
0704-binary-search
0721-accounts-merge
0733-flood-fill
0747-min-cost-climbing-stairs
0819-minimum-swaps-to-make-sequences-increasing
0827-making-a-large-island
0876-hand-of-straights
0882-peak-index-in-a-mountain-array
0890-lemonade-change
0907-koko-eating-bananas
0930-binary-subarrays-with-sum
0931-minimum-falling-path-sum
0974-subarray-sums-divisible-by-k
0992-subarrays-with-k-different-integers
0994-rotting-oranges
0997-find-the-town-judge
1020-number-of-enclaves
1034-subarrays-with-k-different-integers
1046-max-consecutive-ones-iii
1048-longest-string-chain
1050-construct-binary-search-tree-from-preorder-traversal
1056-capacity-to-ship-packages-within-d-days
1091-shortest-path-in-binary-matrix
1111-minimum-score-triangulation-of-polygon
1408-find-the-smallest-divisor-given-a-threshold
1503-reducing-dishes
1538-maximum-points-you-can-obtain-from-cards
1547-minimum-cost-to-cut-a-stick
1594-maximum-non-negative-product-in-a-matrix
1605-minimum-number-of-days-to-make-m-bouquets
1631-path-with-minimum-effort
1646-kth-missing-positive-number
1658-minimum-operations-to-reduce-x-to-zero
1877-minimize-maximum-pair-sum-in-array
1952-minimum-sideway-jumps
2047-find-a-peak-element-ii
2271-rearrange-array-elements-by-sign
2943-maximize-area-of-square-hole-in-grid
3314-construct-the-minimum-bitwise-array-i
3315-construct-the-minimum-bitwise-array-ii
3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii
3546-equal-sum-grid-partition-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
0035-search-insert-position
0074-search-a-2d-matrix
0081-search-in-rotated-sorted-array-ii
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0240-search-a-2d-matrix-ii
0300-longest-increasing-subsequence
0354-russian-doll-envelopes
0410-split-array-largest-sum
0540-single-element-in-a-sorted-array
0704-binary-search
0882-peak-index-in-a-mountain-array
0907-koko-eating-bananas
1046-max-consecutive-ones-iii
1056-capacity-to-ship-packages-within-d-days
1408-find-the-smallest-divisor-given-a-threshold
1605-minimum-number-of-days-to-make-m-bouquets
1631-path-with-minimum-effort
1646-kth-missing-positive-number
1658-minimum-operations-to-reduce-x-to-zero
2047-find-a-peak-element-ii

Dynamic Programming

0005-longest-palindromic-substring
0010-regular-expression-matching
0022-generate-parentheses
0044-wildcard-matching
0053-maximum-subarray
0062-unique-paths
0063-unique-paths-ii
0064-minimum-path-sum
0070-climbing-stairs
0072-edit-distance
0115-distinct-subsequences
0120-triangle
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0123-best-time-to-buy-and-sell-stock-iii
0124-binary-tree-maximum-path-sum
0132-palindrome-partitioning-ii
0152-maximum-product-subarray
0188-best-time-to-buy-and-sell-stock-iv
0198-house-robber
0213-house-robber-ii
0300-longest-increasing-subsequence
0309-best-time-to-buy-and-sell-stock-with-cooldown
0312-burst-balloons
0322-coin-change
0354-russian-doll-envelopes
0368-largest-divisible-subset
0410-split-array-largest-sum
0416-partition-equal-subset-sum
0494-target-sum
0516-longest-palindromic-subsequence
0518-coin-change-ii
0542-01-matrix
0583-delete-operation-for-two-strings
0673-number-of-longest-increasing-subsequence
0747-min-cost-climbing-stairs
0787-cheapest-flights-within-k-stops
0819-minimum-swaps-to-make-sequences-increasing
0931-minimum-falling-path-sum
1048-longest-string-chain
1092-shortest-common-supersequence
1111-minimum-score-triangulation-of-polygon
1143-longest-common-subsequence
1312-minimum-insertion-steps-to-make-a-string-palindrome
1334-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance
1503-reducing-dishes
1547-minimum-cost-to-cut-a-stick
1594-maximum-non-negative-product-in-a-matrix
1952-minimum-sideway-jumps
1976-number-of-ways-to-arrive-at-destination

Greedy

0044-wildcard-matching
0122-best-time-to-buy-and-sell-stock-ii
0410-split-array-largest-sum
0455-assign-cookies
0621-task-scheduler
0876-hand-of-straights
0890-lemonade-change
1503-reducing-dishes
1877-minimize-maximum-pair-sum-in-array
1952-minimum-sideway-jumps
2032-largest-odd-number-in-string

Prefix Sum

0410-split-array-largest-sum
0523-continuous-subarray-sum
0560-subarray-sum-equals-k
0930-binary-subarrays-with-sum
0974-subarray-sums-divisible-by-k
1046-max-consecutive-ones-iii
1538-maximum-points-you-can-obtain-from-cards
1658-minimum-operations-to-reduce-x-to-zero
3546-equal-sum-grid-partition-i

Divide and Conquer

0004-median-of-two-sorted-arrays
0023-merge-k-sorted-lists
0053-maximum-subarray
0148-sort-list
0169-majority-element
0215-kth-largest-element-in-an-array
0240-search-a-2d-matrix-ii

Math

0002-add-two-numbers
0048-rotate-image
0050-powx-n
0062-unique-paths
0070-climbing-stairs
0189-rotate-array
0368-largest-divisible-subset
0523-continuous-subarray-sum
2032-largest-odd-number-in-string
2050-count-good-numbers

Two Pointers

0005-longest-palindromic-substring
0019-remove-nth-node-from-end-of-list
0028-find-the-index-of-the-first-occurrence-in-a-string
0031-next-permutation
0075-sort-colors
0141-linked-list-cycle
0142-linked-list-cycle-ii
0148-sort-list
0151-reverse-words-in-a-string
0160-intersection-of-two-linked-lists
0189-rotate-array
0234-palindrome-linked-list
0455-assign-cookies
0696-count-binary-substrings
0908-middle-of-the-linked-list
0953-reverse-only-letters
1048-longest-string-chain
1877-minimize-maximum-pair-sum-in-array
2216-delete-the-middle-node-of-a-linked-list
2271-rearrange-array-elements-by-sign

Matrix

0048-rotate-image
0054-spiral-matrix
0063-unique-paths-ii
0064-minimum-path-sum
0074-search-a-2d-matrix
0130-surrounded-regions
0200-number-of-islands
0240-search-a-2d-matrix-ii
0542-01-matrix
0733-flood-fill
0827-making-a-large-island
0931-minimum-falling-path-sum
0994-rotting-oranges
1020-number-of-enclaves
1091-shortest-path-in-binary-matrix
1594-maximum-non-negative-product-in-a-matrix
1631-path-with-minimum-effort
2047-find-a-peak-element-ii
3546-equal-sum-grid-partition-i

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0017-letter-combinations-of-a-phone-number
0076-minimum-window-substring
0128-longest-consecutive-sequence
0141-linked-list-cycle
0142-linked-list-cycle-ii
0146-lru-cache
0160-intersection-of-two-linked-lists
0169-majority-element
0205-isomorphic-strings
0242-valid-anagram
0424-longest-repeating-character-replacement
0451-sort-characters-by-frequency
0523-continuous-subarray-sum
0560-subarray-sum-equals-k
0621-task-scheduler
0721-accounts-merge
0876-hand-of-straights
0893-all-nodes-distance-k-in-binary-tree
0930-binary-subarrays-with-sum
0974-subarray-sums-divisible-by-k
0992-subarrays-with-k-different-integers
0997-find-the-town-judge
1029-vertical-order-traversal-of-a-binary-tree
1034-subarrays-with-k-different-integers
1048-longest-string-chain
1358-number-of-substrings-containing-all-three-characters
1460-number-of-substrings-containing-all-three-characters
1658-minimum-operations-to-reduce-x-to-zero
1890-sum-of-beauty-of-all-substrings
3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii

Sorting

0075-sort-colors
0148-sort-list
0169-majority-element
0215-kth-largest-element-in-an-array
0242-valid-anagram
0354-russian-doll-envelopes
0368-largest-divisible-subset
0451-sort-characters-by-frequency
0455-assign-cookies
0621-task-scheduler
0721-accounts-merge
0876-hand-of-straights
1029-vertical-order-traversal-of-a-binary-tree
1048-longest-string-chain
1503-reducing-dishes
1547-minimum-cost-to-cut-a-stick
1877-minimize-maximum-pair-sum-in-array
2943-maximize-area-of-square-hole-in-grid

Counting

0169-majority-element
0451-sort-characters-by-frequency
0621-task-scheduler
0992-subarrays-with-k-different-integers
1034-subarrays-with-k-different-integers
1890-sum-of-beauty-of-all-substrings

Simulation

0054-spiral-matrix
2271-rearrange-array-elements-by-sign
3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii

Union Find

0128-longest-consecutive-sequence
0130-surrounded-regions
0785-is-graph-bipartite
1020-number-of-enclaves
1319-number-of-operations-to-make-network-connected
1631-path-with-minimum-effort

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0010-regular-expression-matching
0014-longest-common-prefix
0017-letter-combinations-of-a-phone-number
0022-generate-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string
0044-wildcard-matching
0072-edit-distance
0076-minimum-window-substring
0115-distinct-subsequences
0132-palindrome-partitioning-ii
0151-reverse-words-in-a-string
0205-isomorphic-strings
0214-shortest-palindrome
0242-valid-anagram
0424-longest-repeating-character-replacement
0451-sort-characters-by-frequency
0516-longest-palindromic-subsequence
0583-delete-operation-for-two-strings
0696-count-binary-substrings
0721-accounts-merge
0812-rotate-string
0953-reverse-only-letters
1048-longest-string-chain
1092-shortest-common-supersequence
1143-longest-common-subsequence
1312-minimum-insertion-steps-to-make-a-string-palindrome
1358-number-of-substrings-containing-all-three-characters
1392-longest-happy-prefix
1460-number-of-substrings-containing-all-three-characters
1737-maximum-nesting-depth-of-the-parentheses
1890-sum-of-beauty-of-all-substrings
2032-largest-odd-number-in-string

Trie

0014-longest-common-prefix

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string
0214-shortest-palindrome
0812-rotate-string
1392-longest-happy-prefix

Heap (Priority Queue)

0023-merge-k-sorted-lists
0215-kth-largest-element-in-an-array
0451-sort-characters-by-frequency
0621-task-scheduler
0787-cheapest-flights-within-k-stops
0789-kth-largest-element-in-a-stream
1631-path-with-minimum-effort
3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii

Bucket Sort

0451-sort-characters-by-frequency

Stack

0114-flatten-binary-tree-to-linked-list
0234-palindrome-linked-list
1050-construct-binary-search-tree-from-preorder-traversal
1737-maximum-nesting-depth-of-the-parentheses

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0023-merge-k-sorted-lists
0114-flatten-binary-tree-to-linked-list
0141-linked-list-cycle
0142-linked-list-cycle-ii
0146-lru-cache
0148-sort-list
0160-intersection-of-two-linked-lists
0206-reverse-linked-list
0234-palindrome-linked-list
0237-delete-node-in-a-linked-list
0328-odd-even-linked-list
0908-middle-of-the-linked-list
2216-delete-the-middle-node-of-a-linked-list
3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii

Recursion

0002-add-two-numbers
0010-regular-expression-matching
0044-wildcard-matching
0050-powx-n
0206-reverse-linked-list
0234-palindrome-linked-list
2050-count-good-numbers

Merge Sort

0023-merge-k-sorted-lists
0148-sort-list

Backtracking

0017-letter-combinations-of-a-phone-number
0022-generate-parentheses
0039-combination-sum
0040-combination-sum-ii
0078-subsets
0090-subsets-ii
0216-combination-sum-iii
0494-target-sum

Bit Manipulation

0078-subsets
0090-subsets-ii
3314-construct-the-minimum-bitwise-array-i
3315-construct-the-minimum-bitwise-array-ii

Sliding Window

0003-longest-substring-without-repeating-characters
0076-minimum-window-substring
0424-longest-repeating-character-replacement
0930-binary-subarrays-with-sum
0992-subarrays-with-k-different-integers
1034-subarrays-with-k-different-integers
1046-max-consecutive-ones-iii
1358-number-of-substrings-containing-all-three-characters
1460-number-of-substrings-containing-all-three-characters
1538-maximum-points-you-can-obtain-from-cards
1658-minimum-operations-to-reduce-x-to-zero

Tree

0098-validate-binary-search-tree
0100-same-tree
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0110-balanced-binary-tree
0114-flatten-binary-tree-to-linked-list
0124-binary-tree-maximum-path-sum
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0236-lowest-common-ancestor-of-a-binary-tree
0450-delete-node-in-a-bst
0543-diameter-of-binary-tree
0662-maximum-width-of-binary-tree
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree
0789-kth-largest-element-in-a-stream
0893-all-nodes-distance-k-in-binary-tree
1029-vertical-order-traversal-of-a-binary-tree
1050-construct-binary-search-tree-from-preorder-traversal

Depth-First Search

0098-validate-binary-search-tree
0100-same-tree
0104-maximum-depth-of-binary-tree
0110-balanced-binary-tree
0114-flatten-binary-tree-to-linked-list
0124-binary-tree-maximum-path-sum
0130-surrounded-regions
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
0543-diameter-of-binary-tree
0662-maximum-width-of-binary-tree
0721-accounts-merge
0733-flood-fill
0785-is-graph-bipartite
0787-cheapest-flights-within-k-stops
0802-find-eventual-safe-states
0827-making-a-large-island
0893-all-nodes-distance-k-in-binary-tree
1020-number-of-enclaves
1029-vertical-order-traversal-of-a-binary-tree
1319-number-of-operations-to-make-network-connected
1631-path-with-minimum-effort

Breadth-First Search

0100-same-tree
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0130-surrounded-regions
0200-number-of-islands
0207-course-schedule
0210-course-schedule-ii
0322-coin-change
0542-01-matrix
0662-maximum-width-of-binary-tree
0721-accounts-merge
0733-flood-fill
0785-is-graph-bipartite
0787-cheapest-flights-within-k-stops
0802-find-eventual-safe-states
0827-making-a-large-island
0893-all-nodes-distance-k-in-binary-tree
0994-rotting-oranges
1020-number-of-enclaves
1029-vertical-order-traversal-of-a-binary-tree
1091-shortest-path-in-binary-matrix
1319-number-of-operations-to-make-network-connected
1631-path-with-minimum-effort

Binary Tree

0098-validate-binary-search-tree
0100-same-tree
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0110-balanced-binary-tree
0114-flatten-binary-tree-to-linked-list
0124-binary-tree-maximum-path-sum
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0236-lowest-common-ancestor-of-a-binary-tree
0450-delete-node-in-a-bst
0543-diameter-of-binary-tree
0662-maximum-width-of-binary-tree
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree
0789-kth-largest-element-in-a-stream
0893-all-nodes-distance-k-in-binary-tree
1029-vertical-order-traversal-of-a-binary-tree
1050-construct-binary-search-tree-from-preorder-traversal

Binary Search Tree

0098-validate-binary-search-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0450-delete-node-in-a-bst
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree
0789-kth-largest-element-in-a-stream
1050-construct-binary-search-tree-from-preorder-traversal

Monotonic Stack

1050-construct-binary-search-tree-from-preorder-traversal

Quickselect

0215-kth-largest-element-in-an-array

Design

0146-lru-cache
0789-kth-largest-element-in-a-stream

Data Stream

0789-kth-largest-element-in-a-stream

Database

0175-combine-two-tables
0176-second-highest-salary
0177-nth-highest-salary
0181-employees-earning-more-than-their-managers
0182-duplicate-emails

Graph

0207-course-schedule
0210-course-schedule-ii
0785-is-graph-bipartite
0787-cheapest-flights-within-k-stops
0802-find-eventual-safe-states
1319-number-of-operations-to-make-network-connected
1334-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance

Topological Sort

0207-course-schedule
0210-course-schedule-ii
0802-find-eventual-safe-states
1976-number-of-ways-to-arrive-at-destination

Shortest Path

0787-cheapest-flights-within-k-stops
1334-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance
1976-number-of-ways-to-arrive-at-destination

Memoization

0070-climbing-stairs

Rolling Hash

0214-shortest-palindrome
1392-longest-happy-prefix

Hash Function

0214-shortest-palindrome
1392-longest-happy-prefix

Binary Indexed Tree

0673-number-of-longest-increasing-subsequence

Segment Tree

0673-number-of-longest-increasing-subsequence

Graph Theory

0785-is-graph-bipartite
0997-find-the-town-judge
1319-number-of-operations-to-make-network-connected
1976-number-of-ways-to-arrive-at-destination

Union-Find

0200-number-of-islands
0721-accounts-merge
0785-is-graph-bipartite
0827-making-a-large-island
1319-number-of-operations-to-make-network-connected
1631-path-with-minimum-effort

Doubly-Linked List

0146-lru-cache
3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii

Ordered Set

3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii

Combinatorics

0062-unique-paths

Enumeration

3546-equal-sum-grid-partition-i

Longest Common Subsequence

1092-shortest-common-supersequence