Leetcode

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

LeetCode Topics

Array

0011-container-with-most-water
0015-3sum
0026-remove-duplicates-from-sorted-array
0035-search-insert-position
0036-valid-sudoku
0039-combination-sum
0045-jump-game-ii
0048-rotate-image
0049-group-anagrams
0053-maximum-subarray
0054-spiral-matrix
0055-jump-game
0056-merge-intervals
0057-insert-interval
0063-unique-paths-ii
0064-minimum-path-sum
0066-plus-one
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0079-word-search
0080-remove-duplicates-from-sorted-array-ii
0088-merge-sorted-array
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0128-longest-consecutive-sequence
0130-surrounded-regions
0134-gas-station
0136-single-number
0137-single-number-ii
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
0209-minimum-size-subarray-sum
0215-kth-largest-element-in-an-array
0221-maximal-square
0238-product-of-array-except-self
0274-h-index
0289-game-of-life
0300-longest-increasing-subsequence
0322-coin-change
0373-find-k-pairs-with-smallest-sums
0380-insert-delete-getrandom-o1
0399-evaluate-division
0452-minimum-number-of-arrows-to-burst-balloons
0772-construct-quad-tree
0945-snakes-and-ladders
0954-maximum-sum-circular-subarray

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
0028-find-the-index-of-the-first-occurrence-in-a-string
0061-rotate-list
0080-remove-duplicates-from-sorted-array-ii
0082-remove-duplicates-from-sorted-list-ii
0086-partition-list
0088-merge-sorted-array
0125-valid-palindrome
0141-linked-list-cycle
0148-sort-list
0151-reverse-words-in-a-string
0167-two-sum-ii-input-array-is-sorted
0189-rotate-array
0392-is-subsequence

Math

0002-add-two-numbers
0009-palindrome-number
0012-integer-to-roman
0048-rotate-image
0066-plus-one
0069-sqrtx
0070-climbing-stairs
0150-evaluate-reverse-polish-notation
0172-factorial-trailing-zeroes
0189-rotate-array
0380-insert-delete-getrandom-o1

Dynamic Programming

0005-longest-palindromic-substring
0022-generate-parentheses
0045-jump-game-ii
0053-maximum-subarray
0055-jump-game
0063-unique-paths-ii
0064-minimum-path-sum
0070-climbing-stairs
0072-edit-distance
0097-interleaving-string
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0139-word-break
0198-house-robber
0221-maximal-square
0300-longest-increasing-subsequence
0322-coin-change
0392-is-subsequence
0954-maximum-sum-circular-subarray

Greedy

0011-container-with-most-water
0045-jump-game-ii
0055-jump-game
0122-best-time-to-buy-and-sell-stock-ii
0134-gas-station
0452-minimum-number-of-arrows-to-burst-balloons

Sorting

0015-3sum
0049-group-anagrams
0056-merge-intervals
0088-merge-sorted-array
0148-sort-list
0169-majority-element
0215-kth-largest-element-in-an-array
0274-h-index
0452-minimum-number-of-arrows-to-burst-balloons

Counting Sort

0169-majority-element
0274-h-index

Hash Table

0003-longest-substring-without-repeating-characters
0012-integer-to-roman
0017-letter-combinations-of-a-phone-number
0036-valid-sudoku
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
0128-longest-consecutive-sequence
0133-clone-graph
0138-copy-list-with-random-pointer
0139-word-break
0141-linked-list-cycle
0146-lru-cache
0169-majority-element
0205-isomorphic-strings
0208-implement-trie-prefix-tree
0290-word-pattern
0380-insert-delete-getrandom-o1
0433-minimum-genetic-mutation

Design

0146-lru-cache
0155-min-stack
0173-binary-search-tree-iterator
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0380-insert-delete-getrandom-o1

Randomized

0380-insert-delete-getrandom-o1

Prefix Sum

0209-minimum-size-subarray-sum
0238-product-of-array-except-self

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0006-zigzag-conversion
0012-integer-to-roman
0017-letter-combinations-of-a-phone-number
0022-generate-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string
0049-group-anagrams
0071-simplify-path
0072-edit-distance
0079-word-search
0097-interleaving-string
0125-valid-palindrome
0139-word-break
0151-reverse-words-in-a-string
0205-isomorphic-strings
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure
0290-word-pattern
0392-is-subsequence
0399-evaluate-division
0433-minimum-genetic-mutation

Binary Search

0035-search-insert-position
0069-sqrtx
0074-search-a-2d-matrix
0153-find-minimum-in-rotated-sorted-array
0167-two-sum-ii-input-array-is-sorted
0209-minimum-size-subarray-sum
0222-count-complete-tree-nodes
0300-longest-increasing-subsequence

Sliding Window

0003-longest-substring-without-repeating-characters
0209-minimum-size-subarray-sum

Matrix

0036-valid-sudoku
0048-rotate-image
0054-spiral-matrix
0063-unique-paths-ii
0064-minimum-path-sum
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0079-word-search
0130-surrounded-regions
0200-number-of-islands
0221-maximal-square
0289-game-of-life
0772-construct-quad-tree
0945-snakes-and-ladders

Simulation

0054-spiral-matrix
0289-game-of-life

Union Find

0128-longest-consecutive-sequence
0130-surrounded-regions
0200-number-of-islands
0399-evaluate-division

Stack

0071-simplify-path
0114-flatten-binary-tree-to-linked-list
0150-evaluate-reverse-polish-notation
0155-min-stack
0173-binary-search-tree-iterator

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0061-rotate-list
0082-remove-duplicates-from-sorted-list-ii
0086-partition-list
0092-reverse-linked-list-ii
0114-flatten-binary-tree-to-linked-list
0117-populating-next-right-pointers-in-each-node-ii
0138-copy-list-with-random-pointer
0141-linked-list-cycle
0146-lru-cache
0148-sort-list

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists

Doubly-Linked List

0146-lru-cache

Tree

0098-validate-binary-search-tree
0100-same-tree
0101-symmetric-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
0112-path-sum
0114-flatten-binary-tree-to-linked-list
0117-populating-next-right-pointers-in-each-node-ii
0129-sum-root-to-leaf-numbers
0173-binary-search-tree-iterator
0199-binary-tree-right-side-view
0222-count-complete-tree-nodes
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0236-lowest-common-ancestor-of-a-binary-tree
0530-minimum-absolute-difference-in-bst
0637-average-of-levels-in-binary-tree
0772-construct-quad-tree

Depth-First Search

0079-word-search
0098-validate-binary-search-tree
0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0112-path-sum
0114-flatten-binary-tree-to-linked-list
0117-populating-next-right-pointers-in-each-node-ii
0129-sum-root-to-leaf-numbers
0130-surrounded-regions
0133-clone-graph
0199-binary-tree-right-side-view
0200-number-of-islands
0207-course-schedule
0210-course-schedule-ii
0211-design-add-and-search-words-data-structure
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0236-lowest-common-ancestor-of-a-binary-tree
0399-evaluate-division
0530-minimum-absolute-difference-in-bst
0637-average-of-levels-in-binary-tree

Breadth-First Search

0100-same-tree
0101-symmetric-tree
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0112-path-sum
0117-populating-next-right-pointers-in-each-node-ii
0130-surrounded-regions
0133-clone-graph
0199-binary-tree-right-side-view
0200-number-of-islands
0207-course-schedule
0210-course-schedule-ii
0226-invert-binary-tree
0322-coin-change
0399-evaluate-division
0433-minimum-genetic-mutation
0530-minimum-absolute-difference-in-bst
0637-average-of-levels-in-binary-tree
0945-snakes-and-ladders

Binary Tree

0098-validate-binary-search-tree
0100-same-tree
0101-symmetric-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
0112-path-sum
0114-flatten-binary-tree-to-linked-list
0117-populating-next-right-pointers-in-each-node-ii
0129-sum-root-to-leaf-numbers
0173-binary-search-tree-iterator
0199-binary-tree-right-side-view
0222-count-complete-tree-nodes
0226-invert-binary-tree
0230-kth-smallest-element-in-a-bst
0236-lowest-common-ancestor-of-a-binary-tree
0530-minimum-absolute-difference-in-bst
0637-average-of-levels-in-binary-tree

Divide and Conquer

0053-maximum-subarray
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0148-sort-list
0169-majority-element
0191-number-of-1-bits
0215-kth-largest-element-in-an-array
0772-construct-quad-tree
0954-maximum-sum-circular-subarray

Binary Search Tree

0098-validate-binary-search-tree
0173-binary-search-tree-iterator
0230-kth-smallest-element-in-a-bst
0530-minimum-absolute-difference-in-bst

Iterator

0173-binary-search-tree-iterator

Bit Manipulation

0136-single-number
0137-single-number-ii
0191-number-of-1-bits
0201-bitwise-and-of-numbers-range
0222-count-complete-tree-nodes

Graph

0133-clone-graph
0207-course-schedule
0210-course-schedule-ii
0399-evaluate-division

Shortest Path

0399-evaluate-division

Topological Sort

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

Trie

0139-word-break
0208-implement-trie-prefix-tree
0211-design-add-and-search-words-data-structure

Backtracking

0017-letter-combinations-of-a-phone-number
0022-generate-parentheses
0039-combination-sum
0077-combinations
0079-word-search

Merge Sort

0148-sort-list

Queue

0954-maximum-sum-circular-subarray

Monotonic Queue

0954-maximum-sum-circular-subarray

Heap (Priority Queue)

0215-kth-largest-element-in-an-array
0373-find-k-pairs-with-smallest-sums

Quickselect

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

Memoization

0070-climbing-stairs
0139-word-break

String Matching

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

Database

0196-delete-duplicate-emails
0197-rising-temperature
0596-classes-with-at-least-5-students
0619-biggest-single-number
0620-not-boring-movies
1135-customers-who-bought-all-products
1161-project-employees-i
1182-game-play-analysis-iv
1292-immediate-food-delivery-ii
1317-monthly-transactions-i
1338-queries-quality-and-percentage
1390-average-selling-price
1415-students-and-examinations
1462-list-the-products-ordered-in-a-period
1625-group-sold-products-by-the-date
1664-find-users-with-valid-e-mails
1670-patients-with-a-condition
1724-customer-who-visited-but-did-not-make-any-transactions
1773-percentage-of-users-attended-a-contest
1801-average-time-of-process-per-machine
1827-invalid-tweets
1877-find-followers-count
1882-the-number-of-employees-which-report-to-each-employee
1908-recyclable-and-low-fat-products
1942-primary-department-for-each-employee
2127-employees-whose-manager-left-the-company