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

LeetCode Topics

Array

0001-two-sum
0011-container-with-most-water
0015-3sum
0026-remove-duplicates-from-sorted-array
0033-search-in-rotated-sorted-array
0036-valid-sudoku
0039-combination-sum
0040-combination-sum-ii
0041-first-missing-positive
0045-jump-game-ii
0046-permutations
0049-group-anagrams
0051-n-queens
0053-maximum-subarray
0055-jump-game
0074-search-a-2d-matrix
0078-subsets
0079-word-search
0090-subsets-ii
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0120-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
0139-word-break
0150-evaluate-reverse-polish-notation
0153-find-minimum-in-rotated-sorted-array
0167-two-sum-ii-input-array-is-sorted
0169-majority-element
0189-rotate-array
0198-house-robber
0200-number-of-islands
0213-house-robber-ii
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0238-product-of-array-except-self
0268-missing-number
0283-move-zeroes
0287-find-the-duplicate-number
0309-best-time-to-buy-and-sell-stock-with-cooldown
0322-coin-change
0334-increasing-triplet-subsequence
0347-top-k-frequent-elements
0416-partition-equal-subset-sum
0417-pacific-atlantic-water-flow
0463-island-perimeter
0473-matchsticks-to-square
0485-max-consecutive-ones
0494-target-sum
0518-coin-change-ii
0621-task-scheduler
0695-max-area-of-island
0698-partition-to-k-equal-sum-subsets
0721-accounts-merge
0733-flood-fill
0747-min-cost-climbing-stairs
0753-open-the-lock
0792-binary-search
0905-length-of-longest-fibonacci-subsequence
0907-koko-eating-bananas
0917-boats-to-save-people
0990-verifying-an-alien-dictionary
1014-k-closest-points-to-origin
1039-find-the-town-judge
1127-last-stone-weight
1130-last-stone-weight-ii
1171-shortest-path-in-binary-matrix
1184-car-pooling
1993-sum-of-all-subset-xor-totals
2432-number-of-zero-filled-subarrays
3621-minimum-operations-to-make-array-values-equal-to-k
3656-minimum-number-of-operations-to-make-elements-in-array-distinct
3788-maximum-unique-subarray-sum-after-deletion
3809-properties-graph

Two Pointers

0005-longest-palindromic-substring
0011-container-with-most-water
0015-3sum
0019-remove-nth-node-from-end-of-list
0026-remove-duplicates-from-sorted-array
0125-valid-palindrome
0141-linked-list-cycle
0143-reorder-list
0151-reverse-words-in-a-string
0167-two-sum-ii-input-array-is-sorted
0189-rotate-array
0283-move-zeroes
0287-find-the-duplicate-number
0295-find-median-from-data-stream
0392-is-subsequence
0567-permutation-in-string
0647-palindromic-substrings
0917-boats-to-save-people

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0017-letter-combinations-of-a-phone-number
0036-valid-sudoku
0041-first-missing-positive
0049-group-anagrams
0076-minimum-window-substring
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0128-longest-consecutive-sequence
0138-copy-list-with-random-pointer
0139-word-break
0141-linked-list-cycle
0169-majority-element
0208-implement-trie-prefix-tree
0217-contains-duplicate
0242-valid-anagram
0268-missing-number
0347-top-k-frequent-elements
0355-design-twitter
0424-longest-repeating-character-replacement
0567-permutation-in-string
0621-task-scheduler
0721-accounts-merge
0753-open-the-lock
0778-reorganize-string
0905-length-of-longest-fibonacci-subsequence
0990-verifying-an-alien-dictionary
1039-find-the-town-judge
1160-letter-tile-possibilities
3621-minimum-operations-to-make-array-values-equal-to-k
3656-minimum-number-of-operations-to-make-elements-in-array-distinct
3788-maximum-unique-subarray-sum-after-deletion
3809-properties-graph

Math

0002-add-two-numbers
0062-unique-paths
0070-climbing-stairs
0150-evaluate-reverse-polish-notation
0189-rotate-array
0268-missing-number
0279-perfect-squares
1014-k-closest-points-to-origin
1993-sum-of-all-subset-xor-totals
2432-number-of-zero-filled-subarrays
2998-count-symmetric-integers

Binary Search

0033-search-in-rotated-sorted-array
0074-search-a-2d-matrix
0153-find-minimum-in-rotated-sorted-array
0167-two-sum-ii-input-array-is-sorted
0268-missing-number
0287-find-the-duplicate-number
0792-binary-search
0907-koko-eating-bananas

Bit Manipulation

0078-subsets
0090-subsets-ii
0136-single-number
0191-number-of-1-bits
0268-missing-number
0287-find-the-duplicate-number
0338-counting-bits
0473-matchsticks-to-square
0698-partition-to-k-equal-sum-subsets
1993-sum-of-all-subset-xor-totals

Sorting

0015-3sum
0049-group-anagrams
0169-majority-element
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0242-valid-anagram
0268-missing-number
0295-find-median-from-data-stream
0347-top-k-frequent-elements
0621-task-scheduler
0721-accounts-merge
0778-reorganize-string
0917-boats-to-save-people
1014-k-closest-points-to-origin
1184-car-pooling

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0006-zigzag-conversion
0014-longest-common-prefix
0017-letter-combinations-of-a-phone-number
0020-valid-parentheses
0022-generate-parentheses
0049-group-anagrams
0076-minimum-window-substring
0079-word-search
0091-decode-ways
0125-valid-palindrome
0131-palindrome-partitioning
0139-word-break
0151-reverse-words-in-a-string
0208-implement-trie-prefix-tree
0242-valid-anagram
0297-serialize-and-deserialize-binary-tree
0392-is-subsequence
0424-longest-repeating-character-replacement
0567-permutation-in-string
0647-palindromic-substrings
0721-accounts-merge
0753-open-the-lock
0778-reorganize-string
0990-verifying-an-alien-dictionary
1160-letter-tile-possibilities
1250-longest-common-subsequence
1304-longest-happy-string

Divide and Conquer

0023-merge-k-sorted-lists
0053-maximum-subarray
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0169-majority-element
0191-number-of-1-bits
0215-kth-largest-element-in-an-array
0347-top-k-frequent-elements
1014-k-closest-points-to-origin

Heap (Priority Queue)

0023-merge-k-sorted-lists
0215-kth-largest-element-in-an-array
0295-find-median-from-data-stream
0347-top-k-frequent-elements
0355-design-twitter
0621-task-scheduler
0778-reorganize-string
0789-kth-largest-element-in-a-stream
1014-k-closest-points-to-origin
1127-last-stone-weight
1184-car-pooling
1304-longest-happy-string

Bucket Sort

0347-top-k-frequent-elements

Counting

0169-majority-element
0347-top-k-frequent-elements
0621-task-scheduler
0778-reorganize-string
1160-letter-tile-possibilities

Quickselect

0215-kth-largest-element-in-an-array
0347-top-k-frequent-elements
1014-k-closest-points-to-origin

Prefix Sum

0238-product-of-array-except-self
1184-car-pooling

Matrix

0036-valid-sudoku
0074-search-a-2d-matrix
0079-word-search
0130-surrounded-regions
0200-number-of-islands
0417-pacific-atlantic-water-flow
0463-island-perimeter
0695-max-area-of-island
0733-flood-fill
1171-shortest-path-in-binary-matrix

Union Find

0128-longest-consecutive-sequence
0130-surrounded-regions
0200-number-of-islands
0547-number-of-provinces
0684-redundant-connection
0695-max-area-of-island
0721-accounts-merge
2121-find-if-path-exists-in-graph
3809-properties-graph

Dynamic Programming

0005-longest-palindromic-substring
0022-generate-parentheses
0045-jump-game-ii
0053-maximum-subarray
0055-jump-game
0062-unique-paths
0070-climbing-stairs
0091-decode-ways
0120-triangle
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0124-binary-tree-maximum-path-sum
0131-palindrome-partitioning
0139-word-break
0198-house-robber
0213-house-robber-ii
0279-perfect-squares
0309-best-time-to-buy-and-sell-stock-with-cooldown
0322-coin-change
0338-counting-bits
0392-is-subsequence
0416-partition-equal-subset-sum
0473-matchsticks-to-square
0494-target-sum
0518-coin-change-ii
0647-palindromic-substrings
0698-partition-to-k-equal-sum-subsets
0747-min-cost-climbing-stairs
0905-length-of-longest-fibonacci-subsequence
1130-last-stone-weight-ii
1250-longest-common-subsequence

Sliding Window

0003-longest-substring-without-repeating-characters
0076-minimum-window-substring
0424-longest-repeating-character-replacement
0567-permutation-in-string

Stack

0020-valid-parentheses
0094-binary-tree-inorder-traversal
0143-reorder-list
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0150-evaluate-reverse-polish-notation

Backtracking

0017-letter-combinations-of-a-phone-number
0022-generate-parentheses
0039-combination-sum
0040-combination-sum-ii
0046-permutations
0051-n-queens
0052-n-queens-ii
0077-combinations
0078-subsets
0079-word-search
0090-subsets-ii
0131-palindrome-partitioning
0473-matchsticks-to-square
0494-target-sum
0698-partition-to-k-equal-sum-subsets
0813-all-paths-from-source-to-target
1160-letter-tile-possibilities
1993-sum-of-all-subset-xor-totals

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0023-merge-k-sorted-lists
0138-copy-list-with-random-pointer
0141-linked-list-cycle
0143-reorder-list
0206-reverse-linked-list
0355-design-twitter

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0143-reorder-list
0206-reverse-linked-list

Tree

0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0100-same-tree
0102-binary-tree-level-order-traversal
0104-maximum-depth-of-binary-tree
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0110-balanced-binary-tree
0124-binary-tree-maximum-path-sum
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0199-binary-tree-right-side-view
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0297-serialize-and-deserialize-binary-tree
0450-delete-node-in-a-bst
0543-diameter-of-binary-tree
0572-subtree-of-another-tree
0617-merge-two-binary-trees
0784-insert-into-a-binary-search-tree
0789-kth-largest-element-in-a-stream
1544-count-good-nodes-in-binary-tree

Depth-First Search

0079-word-search
0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0100-same-tree
0104-maximum-depth-of-binary-tree
0110-balanced-binary-tree
0124-binary-tree-maximum-path-sum
0130-surrounded-regions
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
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0297-serialize-and-deserialize-binary-tree
0417-pacific-atlantic-water-flow
0463-island-perimeter
0543-diameter-of-binary-tree
0547-number-of-provinces
0572-subtree-of-another-tree
0617-merge-two-binary-trees
0684-redundant-connection
0695-max-area-of-island
0721-accounts-merge
0733-flood-fill
0813-all-paths-from-source-to-target
0871-keys-and-rooms
1544-count-good-nodes-in-binary-tree
2121-find-if-path-exists-in-graph
3809-properties-graph

Breadth-First Search

0100-same-tree
0102-binary-tree-level-order-traversal
0104-maximum-depth-of-binary-tree
0130-surrounded-regions
0199-binary-tree-right-side-view
0200-number-of-islands
0207-course-schedule
0210-course-schedule-ii
0226-invert-binary-tree
0279-perfect-squares
0297-serialize-and-deserialize-binary-tree
0322-coin-change
0417-pacific-atlantic-water-flow
0463-island-perimeter
0547-number-of-provinces
0617-merge-two-binary-trees
0684-redundant-connection
0695-max-area-of-island
0721-accounts-merge
0733-flood-fill
0753-open-the-lock
0813-all-paths-from-source-to-target
0871-keys-and-rooms
1171-shortest-path-in-binary-matrix
1544-count-good-nodes-in-binary-tree
2121-find-if-path-exists-in-graph
3809-properties-graph

Binary Tree

0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0100-same-tree
0102-binary-tree-level-order-traversal
0104-maximum-depth-of-binary-tree
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0110-balanced-binary-tree
0124-binary-tree-maximum-path-sum
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0199-binary-tree-right-side-view
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0297-serialize-and-deserialize-binary-tree
0450-delete-node-in-a-bst
0543-diameter-of-binary-tree
0572-subtree-of-another-tree
0617-merge-two-binary-trees
0784-insert-into-a-binary-search-tree
0789-kth-largest-element-in-a-stream
1544-count-good-nodes-in-binary-tree

String Matching

0572-subtree-of-another-tree

Hash Function

0572-subtree-of-another-tree

Geometry

1014-k-closest-points-to-origin

Design

0208-implement-trie-prefix-tree
0295-find-median-from-data-stream
0297-serialize-and-deserialize-binary-tree
0355-design-twitter
0789-kth-largest-element-in-a-stream

Trie

0014-longest-common-prefix
0139-word-break
0208-implement-trie-prefix-tree

Graph

0207-course-schedule
0210-course-schedule-ii
0547-number-of-provinces
0684-redundant-connection
0813-all-paths-from-source-to-target
0871-keys-and-rooms
1039-find-the-town-judge
1661-minimum-number-of-vertices-to-reach-all-nodes
2121-find-if-path-exists-in-graph
3809-properties-graph

Simulation

1184-car-pooling

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
0784-insert-into-a-binary-search-tree
0789-kth-largest-element-in-a-stream

Data Stream

0295-find-median-from-data-stream
0789-kth-largest-element-in-a-stream

Greedy

0011-container-with-most-water
0045-jump-game-ii
0055-jump-game
0122-best-time-to-buy-and-sell-stock-ii
0334-increasing-triplet-subsequence
0621-task-scheduler
0778-reorganize-string
0917-boats-to-save-people
1304-longest-happy-string
3788-maximum-unique-subarray-sum-after-deletion

Topological Sort

0207-course-schedule
0210-course-schedule-ii

Combinatorics

0062-unique-paths
1993-sum-of-all-subset-xor-totals

Enumeration

1993-sum-of-all-subset-xor-totals
2998-count-symmetric-integers

Bitmask

0473-matchsticks-to-square
0698-partition-to-k-equal-sum-subsets

Memoization

0070-climbing-stairs
0139-word-break
0698-partition-to-k-equal-sum-subsets

Merge Sort

0023-merge-k-sorted-lists