leetcode

LeetCode Topics

Array

0001-two-sum
0011-container-with-most-water
0016-3sum-closest
0039-combination-sum
0048-rotate-image
0051-n-queens
0053-maximum-subarray
0054-spiral-matrix
0056-merge-intervals
0057-insert-interval
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0075-sort-colors
0079-word-search
0081-search-in-rotated-sorted-array-ii
0085-maximal-rectangle
0088-merge-sorted-array
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0118-pascals-triangle
0119-pascals-triangle-ii
0121-best-time-to-buy-and-sell-stock
0128-longest-consecutive-sequence
0136-single-number
0162-find-peak-element
0169-majority-element
0200-number-of-islands
0217-contains-duplicate
0238-product-of-array-except-self
0240-search-a-2d-matrix-ii
0268-missing-number
0287-find-the-duplicate-number
0300-longest-increasing-subsequence
0347-top-k-frequent-elements
0373-find-k-pairs-with-smallest-sums
0378-kth-smallest-element-in-a-sorted-matrix
0407-trapping-rain-water-ii
0417-pacific-atlantic-water-flow
0435-non-overlapping-intervals
0442-find-all-duplicates-in-an-array
0448-find-all-numbers-disappeared-in-an-array
0452-minimum-number-of-arrows-to-burst-balloons
0581-shortest-unsorted-continuous-subarray
0621-task-scheduler
0630-course-schedule-iii
0654-maximum-binary-tree
0713-subarray-product-less-than-k
0735-asteroid-collision
0745-find-smallest-letter-greater-than-target
0792-binary-search
0808-number-of-matching-subsequences
0860-design-circular-queue
0882-peak-index-in-a-mountain-array
0940-fruit-into-baskets
1014-k-closest-points-to-origin
1019-squares-of-a-sorted-array
1028-interval-list-intersections
1137-height-checker
1396-count-servers-that-communicate
1476-count-negative-numbers-in-a-sorted-matrix
1482-minimum-number-of-days-to-make-m-bouquets
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1878-check-if-array-is-sorted-and-rotated
2145-grid-game
2533-bitwise-xor-of-all-pairings
2685-first-completely-painted-row-or-column
2766-find-the-prefix-common-array-of-two-arrays
2792-neighboring-bitwise-xor
3219-make-lexicographically-smallest-array-by-swapping-elements
3227-find-missing-and-repeated-values

Binary Search

0074-search-a-2d-matrix
0081-search-in-rotated-sorted-array-ii
0162-find-peak-element
0240-search-a-2d-matrix-ii
0268-missing-number
0278-first-bad-version
0287-find-the-duplicate-number
0300-longest-increasing-subsequence
0378-kth-smallest-element-in-a-sorted-matrix
0713-subarray-product-less-than-k
0745-find-smallest-letter-greater-than-target
0792-binary-search
0808-number-of-matching-subsequences
0882-peak-index-in-a-mountain-array
1476-count-negative-numbers-in-a-sorted-matrix
1482-minimum-number-of-days-to-make-m-bouquets

Math

0002-add-two-numbers
0013-roman-to-integer
0048-rotate-image
0050-powx-n
0268-missing-number
0804-rotated-digits
1014-k-closest-points-to-origin
3227-find-missing-and-repeated-values

Dynamic Programming

0022-generate-parentheses
0053-maximum-subarray
0085-maximal-rectangle
0118-pascals-triangle
0119-pascals-triangle-ii
0121-best-time-to-buy-and-sell-stock
0300-longest-increasing-subsequence
0338-counting-bits
0435-non-overlapping-intervals
0804-rotated-digits
0808-number-of-matching-subsequences

Interactive

0278-first-bad-version

Matrix

0048-rotate-image
0054-spiral-matrix
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0079-word-search
0085-maximal-rectangle
0200-number-of-islands
0240-search-a-2d-matrix-ii
0378-kth-smallest-element-in-a-sorted-matrix
0407-trapping-rain-water-ii
0417-pacific-atlantic-water-flow
1396-count-servers-that-communicate
1476-count-negative-numbers-in-a-sorted-matrix
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
2145-grid-game
2685-first-completely-painted-row-or-column
3227-find-missing-and-repeated-values

String

0003-longest-substring-without-repeating-characters
0006-zigzag-conversion
0013-roman-to-integer
0017-letter-combinations-of-a-phone-number
0022-generate-parentheses
0071-simplify-path
0079-word-search
0208-implement-trie-prefix-tree
0297-serialize-and-deserialize-binary-tree
0409-longest-palindrome
0424-longest-repeating-character-replacement
0451-sort-characters-by-frequency
0520-detect-capital
0567-permutation-in-string
0742-to-lower-case
0782-jewels-and-stones
0808-number-of-matching-subsequences
0851-goat-latin
0874-backspace-string-compare
1320-remove-all-adjacent-duplicates-in-string-ii
2059-unique-length-3-palindromic-subsequences
2304-cells-in-a-range-on-an-excel-sheet
3455-minimum-length-of-string-after-operations

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0013-roman-to-integer
0017-letter-combinations-of-a-phone-number
0073-set-matrix-zeroes
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0128-longest-consecutive-sequence
0133-clone-graph
0141-linked-list-cycle
0142-linked-list-cycle-ii
0169-majority-element
0208-implement-trie-prefix-tree
0217-contains-duplicate
0268-missing-number
0347-top-k-frequent-elements
0409-longest-palindrome
0424-longest-repeating-character-replacement
0442-find-all-duplicates-in-an-array
0448-find-all-numbers-disappeared-in-an-array
0451-sort-characters-by-frequency
0567-permutation-in-string
0621-task-scheduler
0782-jewels-and-stones
0808-number-of-matching-subsequences
0940-fruit-into-baskets
2059-unique-length-3-palindromic-subsequences
2685-first-completely-painted-row-or-column
2766-find-the-prefix-common-array-of-two-arrays
3227-find-missing-and-repeated-values
3455-minimum-length-of-string-after-operations

Greedy

0011-container-with-most-water
0409-longest-palindrome
0435-non-overlapping-intervals
0452-minimum-number-of-arrows-to-burst-balloons
0581-shortest-unsorted-continuous-subarray
0621-task-scheduler
0630-course-schedule-iii
2509-minimize-xor

Sorting

0016-3sum-closest
0056-merge-intervals
0075-sort-colors
0088-merge-sorted-array
0148-sort-list
0169-majority-element
0217-contains-duplicate
0268-missing-number
0347-top-k-frequent-elements
0378-kth-smallest-element-in-a-sorted-matrix
0435-non-overlapping-intervals
0451-sort-characters-by-frequency
0452-minimum-number-of-arrows-to-burst-balloons
0581-shortest-unsorted-continuous-subarray
0621-task-scheduler
0630-course-schedule-iii
0808-number-of-matching-subsequences
1014-k-closest-points-to-origin
1019-squares-of-a-sorted-array
1137-height-checker
3219-make-lexicographically-smallest-array-by-swapping-elements

Counting Sort

0169-majority-element
0347-top-k-frequent-elements
0451-sort-characters-by-frequency
0621-task-scheduler
1137-height-checker
1396-count-servers-that-communicate
3455-minimum-length-of-string-after-operations

Bit Manipulation

0136-single-number
0268-missing-number
0287-find-the-duplicate-number
0338-counting-bits
2059-unique-length-3-palindromic-subsequences
2509-minimize-xor
2533-bitwise-xor-of-all-pairings
2766-find-the-prefix-common-array-of-two-arrays
2792-neighboring-bitwise-xor

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0024-swap-nodes-in-pairs
0061-rotate-list
0083-remove-duplicates-from-sorted-list
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0141-linked-list-cycle
0142-linked-list-cycle-ii
0143-reorder-list
0148-sort-list
0203-remove-linked-list-elements
0234-palindrome-linked-list
0328-odd-even-linked-list
0860-design-circular-queue
0908-middle-of-the-linked-list

Two Pointers

0011-container-with-most-water
0016-3sum-closest
0019-remove-nth-node-from-end-of-list
0061-rotate-list
0075-sort-colors
0088-merge-sorted-array
0141-linked-list-cycle
0142-linked-list-cycle-ii
0143-reorder-list
0148-sort-list
0234-palindrome-linked-list
0287-find-the-duplicate-number
0567-permutation-in-string
0581-shortest-unsorted-continuous-subarray
0874-backspace-string-compare
0908-middle-of-the-linked-list
1019-squares-of-a-sorted-array
1028-interval-list-intersections

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0024-swap-nodes-in-pairs
0050-powx-n
0143-reorder-list
0203-remove-linked-list-elements
0234-palindrome-linked-list

Stack

0071-simplify-path
0085-maximal-rectangle
0094-binary-tree-inorder-traversal
0143-reorder-list
0234-palindrome-linked-list
0581-shortest-unsorted-continuous-subarray
0654-maximum-binary-tree
0735-asteroid-collision
0874-backspace-string-compare
0937-online-stock-span
1320-remove-all-adjacent-duplicates-in-string-ii

Tree

0094-binary-tree-inorder-traversal
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
0107-binary-tree-level-order-traversal-ii
0110-balanced-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0113-path-sum-ii
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0129-sum-root-to-leaf-numbers
0199-binary-tree-right-side-view
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0236-lowest-common-ancestor-of-a-binary-tree
0297-serialize-and-deserialize-binary-tree
0543-diameter-of-binary-tree
0617-merge-two-binary-trees
0637-average-of-levels-in-binary-tree
0654-maximum-binary-tree

Depth-First Search

0079-word-search
0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0110-balanced-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0113-path-sum-ii
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0129-sum-root-to-leaf-numbers
0133-clone-graph
0199-binary-tree-right-side-view
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
0297-serialize-and-deserialize-binary-tree
0417-pacific-atlantic-water-flow
0543-diameter-of-binary-tree
0617-merge-two-binary-trees
0637-average-of-levels-in-binary-tree
0820-find-eventual-safe-states
1396-count-servers-that-communicate
2246-maximum-employees-to-be-invited-to-a-meeting

Binary Tree

0094-binary-tree-inorder-traversal
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
0107-binary-tree-level-order-traversal-ii
0110-balanced-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0113-path-sum-ii
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0129-sum-root-to-leaf-numbers
0199-binary-tree-right-side-view
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0236-lowest-common-ancestor-of-a-binary-tree
0297-serialize-and-deserialize-binary-tree
0543-diameter-of-binary-tree
0617-merge-two-binary-trees
0637-average-of-levels-in-binary-tree
0654-maximum-binary-tree

Simulation

0054-spiral-matrix
0735-asteroid-collision
0874-backspace-string-compare

Design

0208-implement-trie-prefix-tree
0297-serialize-and-deserialize-binary-tree
0860-design-circular-queue
0937-online-stock-span

Queue

0860-design-circular-queue

Monotonic Stack

0085-maximal-rectangle
0581-shortest-unsorted-continuous-subarray
0654-maximum-binary-tree
0937-online-stock-span

Data Stream

0937-online-stock-span

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
0107-binary-tree-level-order-traversal-ii
0111-minimum-depth-of-binary-tree
0112-path-sum
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0133-clone-graph
0199-binary-tree-right-side-view
0200-number-of-islands
0207-course-schedule
0210-course-schedule-ii
0297-serialize-and-deserialize-binary-tree
0407-trapping-rain-water-ii
0417-pacific-atlantic-water-flow
0617-merge-two-binary-trees
0637-average-of-levels-in-binary-tree
0820-find-eventual-safe-states
1396-count-servers-that-communicate
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid

Union Find

0128-longest-consecutive-sequence
0200-number-of-islands
1396-count-servers-that-communicate
3219-make-lexicographically-smallest-array-by-swapping-elements

Binary Search Tree

0098-validate-binary-search-tree
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree

Graph

0133-clone-graph
0207-course-schedule
0210-course-schedule-ii
0820-find-eventual-safe-states
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
2246-maximum-employees-to-be-invited-to-a-meeting

Prefix Sum

0238-product-of-array-except-self
0713-subarray-product-less-than-k
2059-unique-length-3-palindromic-subsequences
2145-grid-game

Topological Sort

0207-course-schedule
0210-course-schedule-ii
0820-find-eventual-safe-states
2246-maximum-employees-to-be-invited-to-a-meeting

Divide and Conquer

0053-maximum-subarray
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0148-sort-list
0169-majority-element
0240-search-a-2d-matrix-ii
0347-top-k-frequent-elements
0654-maximum-binary-tree
1014-k-closest-points-to-origin

Backtracking

0017-letter-combinations-of-a-phone-number
0022-generate-parentheses
0039-combination-sum
0051-n-queens
0079-word-search
0113-path-sum-ii

Trie

0208-implement-trie-prefix-tree
0808-number-of-matching-subsequences

Heap (Priority Queue)

0347-top-k-frequent-elements
0373-find-k-pairs-with-smallest-sums
0378-kth-smallest-element-in-a-sorted-matrix
0407-trapping-rain-water-ii
0451-sort-characters-by-frequency
0621-task-scheduler
0630-course-schedule-iii
1014-k-closest-points-to-origin
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid

Bucket Sort

0347-top-k-frequent-elements
0451-sort-characters-by-frequency

Quickselect

0347-top-k-frequent-elements
1014-k-closest-points-to-origin

Brainteaser

2533-bitwise-xor-of-all-pairings

Geometry

1014-k-closest-points-to-origin

Database

0197-rising-temperature
0570-managers-with-at-least-5-direct-reports
0577-employee-bonus
0584-find-customer-referee
0596-classes-more-than-5-students
0619-biggest-single-number
1135-customers-who-bought-all-products
1155-product-sales-analysis-iii
1161-project-employees-i
1245-user-activity-for-the-past-30-days-i
1292-immediate-food-delivery-ii
1317-monthly-transactions-i
1338-queries-quality-and-percentage
1390-average-selling-price
1415-students-and-examinations
1509-replace-employee-id-with-the-unique-identifier
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
2087-confirmation-rate

Shortest Path

1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid

Sliding Window

0003-longest-substring-without-repeating-characters
0424-longest-repeating-character-replacement
0567-permutation-in-string
0713-subarray-product-less-than-k
0940-fruit-into-baskets

Merge Sort

0148-sort-list

Line Sweep

1028-interval-list-intersections