LeetCode Topics

Array

0001-two-sum
0004-median-of-two-sorted-arrays
0011-container-with-most-water
0016-3sum-closest
0036-valid-sudoku
0039-combination-sum
0040-combination-sum-ii
0041-first-missing-positive
0048-rotate-image
0051-n-queens
0055-jump-game
0056-merge-intervals
0066-plus-one
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0075-sort-colors
0078-subsets
0084-largest-rectangle-in-histogram
0088-merge-sorted-array
0090-subsets-ii
0108-convert-sorted-array-to-binary-search-tree
0118-pascals-triangle
0120-triangle
0128-longest-consecutive-sequence
0134-gas-station
0137-single-number-ii
0152-maximum-product-subarray
0154-find-minimum-in-rotated-sorted-array-ii
0167-two-sum-ii-input-array-is-sorted
0169-majority-element
0204-count-primes
0209-minimum-size-subarray-sum
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0219-contains-duplicate-ii
0229-majority-element-ii
0240-search-a-2d-matrix-ii
0303-range-sum-query-immutable
0407-trapping-rain-water-ii
0413-arithmetic-slices
0417-pacific-atlantic-water-flow
0442-find-all-duplicates-in-an-array
0448-find-all-numbers-disappeared-in-an-array
0455-assign-cookies
0456-132-pattern
0493-reverse-pairs
0503-next-greater-element-ii
0605-can-place-flowers
0611-valid-triangle-number
0628-maximum-product-of-three-numbers
0713-subarray-product-less-than-k
0735-asteroid-collision
0739-daily-temperatures
0830-largest-triangle-area
0907-koko-eating-bananas
0932-monotonic-array
0934-bitwise-ors-of-subarrays
0940-fruit-into-baskets
0948-sort-an-array
1006-vowel-spellchecker
1018-largest-perimeter-triangle
1072-next-greater-node-in-linked-list
1111-minimum-score-triangulation-of-polygon
1130-last-stone-weight-ii
1184-car-pooling
1206-corporate-flight-bookings
1319-unique-number-of-occurrences
1421-find-numbers-with-even-number-of-digits
1426-find-n-unique-integers-sum-up-to-zero
1510-find-lucky-integer-in-an-array
1538-maximum-points-you-can-obtain-from-cards
1586-longest-subarray-of-1s-after-deleting-one-element
1605-minimum-number-of-days-to-make-m-bouquets
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1706-min-cost-to-connect-all-points
1813-maximum-erasure-value
1834-minimum-number-of-people-to-teach
1917-maximum-average-pass-ratio
1951-find-the-winner-of-the-circular-game
2113-find-the-kth-largest-integer-in-the-array
2170-count-number-of-maximum-bitwise-or-subsets
2316-count-hills-and-valleys-in-an-array
2324-find-triangular-sum-of-an-array
2388-replace-elements-in-an-array
2392-successful-pairs-of-spells-and-potions
2429-design-a-food-rating-system
2498-smallest-subarrays-with-maximum-bitwise-or
2503-longest-subarray-with-maximum-bitwise-and
2585-delete-greatest-value-in-each-row
3227-find-missing-and-repeated-values
3234-double-modular-exponentiation
3242-count-elements-with-maximum-frequency
3461-find-the-minimum-area-to-cover-all-ones-i
3522-find-the-power-of-k-size-subarrays-i
3639-zero-array-transformation-i
3643-zero-array-transformation-ii
3685-count-subarrays-of-length-three-with-a-condition
3788-maximum-unique-subarray-sum-after-deletion
3790-fruits-into-baskets-ii
3794-find-the-minimum-amount-of-time-to-brew-potions
3936-split-array-by-prime-indices

Math

0002-add-two-numbers
0029-divide-two-integers
0048-rotate-image
0062-unique-paths
0066-plus-one
0067-add-binary
0069-sqrtx
0070-climbing-stairs
0166-fraction-to-recurring-decimal
0168-excel-sheet-column-title
0172-factorial-trailing-zeroes
0202-happy-number
0204-count-primes
0231-power-of-two
0292-nim-game
0445-add-two-numbers-ii
0507-perfect-number
0628-maximum-product-of-three-numbers
0830-largest-triangle-area
1018-largest-perimeter-triangle
1421-find-numbers-with-even-number-of-digits
1426-find-n-unique-integers-sum-up-to-zero
1440-convert-integer-to-the-sum-of-two-no-zero-integers
1642-water-bottles
1951-find-the-winner-of-the-circular-game
2050-count-good-numbers
2324-find-triangular-sum-of-an-array
2605-count-anagrams
3227-find-missing-and-repeated-values
3234-double-modular-exponentiation
3279-alice-and-bob-playing-flower-game
3336-water-bottles-ii
3371-harshad-number
3462-vowels-game-in-a-string
3830-find-closest-person
3936-split-array-by-prime-indices

Tree

0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0099-recover-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
0108-convert-sorted-array-to-binary-search-tree
0110-balanced-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0124-binary-tree-maximum-path-sum
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0199-binary-tree-right-side-view
0222-count-complete-tree-nodes
0226-invert-binary-tree
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
0450-delete-node-in-a-bst
0530-minimum-absolute-difference-in-bst
0543-diameter-of-binary-tree
0637-average-of-levels-in-binary-tree
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree
1029-vertical-order-traversal-of-a-binary-tree
2461-amount-of-time-for-binary-tree-to-be-infected

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
0111-minimum-depth-of-binary-tree
0112-path-sum
0199-binary-tree-right-side-view
0226-invert-binary-tree
0297-serialize-and-deserialize-binary-tree
0407-trapping-rain-water-ii
0417-pacific-atlantic-water-flow
0530-minimum-absolute-difference-in-bst
0637-average-of-levels-in-binary-tree
1029-vertical-order-traversal-of-a-binary-tree
2461-amount-of-time-for-binary-tree-to-be-infected

Binary Tree

0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0099-recover-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
0108-convert-sorted-array-to-binary-search-tree
0110-balanced-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0124-binary-tree-maximum-path-sum
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0199-binary-tree-right-side-view
0222-count-complete-tree-nodes
0226-invert-binary-tree
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
0450-delete-node-in-a-bst
0530-minimum-absolute-difference-in-bst
0543-diameter-of-binary-tree
0637-average-of-levels-in-binary-tree
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree
1029-vertical-order-traversal-of-a-binary-tree
2461-amount-of-time-for-binary-tree-to-be-infected

Stack

0084-largest-rectangle-in-histogram
0094-binary-tree-inorder-traversal
0143-reorder-list
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0394-decode-string
0402-remove-k-digits
0445-add-two-numbers-ii
0456-132-pattern
0503-next-greater-element-ii
0735-asteroid-collision
0739-daily-temperatures
0937-online-stock-span
1072-next-greater-node-in-linked-list
1818-maximum-score-from-removing-substrings

Depth-First Search

0094-binary-tree-inorder-traversal
0098-validate-binary-search-tree
0099-recover-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
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
0236-lowest-common-ancestor-of-a-binary-tree
0297-serialize-and-deserialize-binary-tree
0417-pacific-atlantic-water-flow
0530-minimum-absolute-difference-in-bst
0543-diameter-of-binary-tree
0637-average-of-levels-in-binary-tree
1029-vertical-order-traversal-of-a-binary-tree
2461-amount-of-time-for-binary-tree-to-be-infected

Dynamic Programming

0005-longest-palindromic-substring
0022-generate-parentheses
0055-jump-game
0062-unique-paths
0070-climbing-stairs
0118-pascals-triangle
0120-triangle
0124-binary-tree-maximum-path-sum
0131-palindrome-partitioning
0152-maximum-product-subarray
0392-is-subsequence
0413-arithmetic-slices
0934-bitwise-ors-of-subarrays
1111-minimum-score-triangulation-of-polygon
1130-last-stone-weight-ii
1586-longest-subarray-of-1s-after-deleting-one-element

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
0073-set-matrix-zeroes
0128-longest-consecutive-sequence
0166-fraction-to-recurring-decimal
0169-majority-element
0187-repeated-dna-sequences
0202-happy-number
0217-contains-duplicate
0219-contains-duplicate-ii
0229-majority-element-ii
0424-longest-repeating-character-replacement
0438-find-all-anagrams-in-a-string
0442-find-all-duplicates-in-an-array
0448-find-all-numbers-disappeared-in-an-array
0940-fruit-into-baskets
1006-vowel-spellchecker
1029-vertical-order-traversal-of-a-binary-tree
1264-maximum-number-of-words-you-can-type
1319-unique-number-of-occurrences
1460-number-of-substrings-containing-all-three-characters
1510-find-lucky-integer-in-an-array
1813-maximum-erasure-value
1834-minimum-number-of-people-to-teach
2053-check-if-all-characters-have-equal-number-of-occurrences
2388-replace-elements-in-an-array
2429-design-a-food-rating-system
2461-amount-of-time-for-binary-tree-to-be-infected
2605-count-anagrams
3227-find-missing-and-repeated-values
3242-count-elements-with-maximum-frequency
3678-design-task-manager
3788-maximum-unique-subarray-sum-after-deletion
3872-find-most-frequent-vowel-and-consonant

Matrix

0036-valid-sudoku
0048-rotate-image
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0240-search-a-2d-matrix-ii
0407-trapping-rain-water-ii
0417-pacific-atlantic-water-flow
2585-delete-greatest-value-in-each-row
3227-find-missing-and-repeated-values
3461-find-the-minimum-area-to-cover-all-ones-i

Binary Search

0004-median-of-two-sorted-arrays
0069-sqrtx
0074-search-a-2d-matrix
0154-find-minimum-in-rotated-sorted-array-ii
0167-two-sum-ii-input-array-is-sorted
0209-minimum-size-subarray-sum
0222-count-complete-tree-nodes
0240-search-a-2d-matrix-ii
0456-132-pattern
0493-reverse-pairs
0611-valid-triangle-number
0713-subarray-product-less-than-k
0907-koko-eating-bananas
1605-minimum-number-of-days-to-make-m-bouquets
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
2392-successful-pairs-of-spells-and-potions
2498-smallest-subarrays-with-maximum-bitwise-or
3643-zero-array-transformation-ii
3790-fruits-into-baskets-ii

Monotonic Stack

0084-largest-rectangle-in-histogram
0402-remove-k-digits
0456-132-pattern
0503-next-greater-element-ii
0739-daily-temperatures
0937-online-stock-span
1072-next-greater-node-in-linked-list

Ordered Set

0456-132-pattern
0493-reverse-pairs
2429-design-a-food-rating-system
3678-design-task-manager
3790-fruits-into-baskets-ii

Bit Manipulation

0029-divide-two-integers
0067-add-binary
0078-subsets
0090-subsets-ii
0137-single-number-ii
0187-repeated-dna-sequences
0222-count-complete-tree-nodes
0231-power-of-two
0476-number-complement
0934-bitwise-ors-of-subarrays
2170-count-number-of-maximum-bitwise-or-subsets
2498-smallest-subarrays-with-maximum-bitwise-or
2503-longest-subarray-with-maximum-bitwise-and
2837-minimum-operations-to-make-the-integer-zero
3453-generate-binary-strings-without-adjacent-zeros

Sorting

0016-3sum-closest
0056-merge-intervals
0075-sort-colors
0088-merge-sorted-array
0169-majority-element
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0229-majority-element-ii
0455-assign-cookies
0611-valid-triangle-number
0628-maximum-product-of-three-numbers
0948-sort-an-array
1018-largest-perimeter-triangle
1029-vertical-order-traversal-of-a-binary-tree
1184-car-pooling
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
2113-find-the-kth-largest-integer-in-the-array
2392-successful-pairs-of-spells-and-potions
2585-delete-greatest-value-in-each-row
2887-sort-vowels-in-a-string

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0143-reorder-list
0231-power-of-two
0394-decode-string
1951-find-the-winner-of-the-circular-game
2050-count-good-numbers

Queue

1951-find-the-winner-of-the-circular-game

Simulation

0067-add-binary
0735-asteroid-collision
1184-car-pooling
1642-water-bottles
1951-find-the-winner-of-the-circular-game
2260-divide-a-string-into-groups-of-size-k
2324-find-triangular-sum-of-an-array
2388-replace-elements-in-an-array
2585-delete-greatest-value-in-each-row
3234-double-modular-exponentiation
3336-water-bottles-ii
3790-fruits-into-baskets-ii
3794-find-the-minimum-amount-of-time-to-brew-potions

Two Pointers

0005-longest-palindromic-substring
0011-container-with-most-water
0016-3sum-closest
0061-rotate-list
0075-sort-colors
0088-merge-sorted-array
0125-valid-palindrome
0143-reorder-list
0151-reverse-words-in-a-string
0165-compare-version-numbers
0167-two-sum-ii-input-array-is-sorted
0202-happy-number
0344-reverse-string
0392-is-subsequence
0443-string-compression
0455-assign-cookies
0611-valid-triangle-number
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
2392-successful-pairs-of-spells-and-potions

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0006-zigzag-conversion
0008-string-to-integer-atoi
0017-letter-combinations-of-a-phone-number
0022-generate-parentheses
0058-length-of-last-word
0067-add-binary
0125-valid-palindrome
0131-palindrome-partitioning
0151-reverse-words-in-a-string
0165-compare-version-numbers
0166-fraction-to-recurring-decimal
0168-excel-sheet-column-title
0187-repeated-dna-sequences
0297-serialize-and-deserialize-binary-tree
0344-reverse-string
0392-is-subsequence
0394-decode-string
0402-remove-k-digits
0424-longest-repeating-character-replacement
0438-find-all-anagrams-in-a-string
0443-string-compression
0459-repeated-substring-pattern
1006-vowel-spellchecker
1264-maximum-number-of-words-you-can-type
1302-delete-characters-to-make-fancy-string
1460-number-of-substrings-containing-all-three-characters
1660-thousand-separator
1818-maximum-score-from-removing-substrings
1967-longest-substring-of-all-vowels-in-order
2053-check-if-all-characters-have-equal-number-of-occurrences
2113-find-the-kth-largest-integer-in-the-array
2260-divide-a-string-into-groups-of-size-k
2337-remove-digit-from-number-to-maximize-result
2429-design-a-food-rating-system
2605-count-anagrams
2887-sort-vowels-in-a-string
3396-valid-word
3453-generate-binary-strings-without-adjacent-zeros
3462-vowels-game-in-a-string
3872-find-most-frequent-vowel-and-consonant

Backtracking

0017-letter-combinations-of-a-phone-number
0022-generate-parentheses
0039-combination-sum
0040-combination-sum-ii
0051-n-queens
0078-subsets
0090-subsets-ii
0131-palindrome-partitioning
2170-count-number-of-maximum-bitwise-or-subsets
3453-generate-binary-strings-without-adjacent-zeros

Divide and Conquer

0004-median-of-two-sorted-arrays
0108-convert-sorted-array-to-binary-search-tree
0169-majority-element
0215-kth-largest-element-in-an-array
0240-search-a-2d-matrix-ii
0493-reverse-pairs
0948-sort-an-array
2113-find-the-kth-largest-integer-in-the-array

Binary Search Tree

0098-validate-binary-search-tree
0099-recover-binary-search-tree
0108-convert-sorted-array-to-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
0530-minimum-absolute-difference-in-bst
0783-search-in-a-binary-search-tree
0784-insert-into-a-binary-search-tree

Greedy

0011-container-with-most-water
0055-jump-game
0134-gas-station
0402-remove-k-digits
0455-assign-cookies
0605-can-place-flowers
0611-valid-triangle-number
1018-largest-perimeter-triangle
1818-maximum-score-from-removing-substrings
1834-minimum-number-of-people-to-teach
1917-maximum-average-pass-ratio
2337-remove-digit-from-number-to-maximize-result
3788-maximum-unique-subarray-sum-after-deletion

Counting

0169-majority-element
0229-majority-element-ii
1510-find-lucky-integer-in-an-array
2053-check-if-all-characters-have-equal-number-of-occurrences
2605-count-anagrams
3242-count-elements-with-maximum-frequency
3872-find-most-frequent-vowel-and-consonant

Sliding Window

0003-longest-substring-without-repeating-characters
0187-repeated-dna-sequences
0209-minimum-size-subarray-sum
0219-contains-duplicate-ii
0413-arithmetic-slices
0424-longest-repeating-character-replacement
0438-find-all-anagrams-in-a-string
0713-subarray-product-less-than-k
0940-fruit-into-baskets
1460-number-of-substrings-containing-all-three-characters
1538-maximum-points-you-can-obtain-from-cards
1586-longest-subarray-of-1s-after-deleting-one-element
1813-maximum-erasure-value
1967-longest-substring-of-all-vowels-in-order
2498-smallest-subarrays-with-maximum-bitwise-or
3522-find-the-power-of-k-size-subarrays-i

Linked List

0002-add-two-numbers
0021-merge-two-sorted-lists
0061-rotate-list
0083-remove-duplicates-from-sorted-list
0143-reorder-list
0445-add-two-numbers-ii
1072-next-greater-node-in-linked-list

Heap (Priority Queue)

0215-kth-largest-element-in-an-array
0407-trapping-rain-water-ii
0948-sort-an-array
1184-car-pooling
1917-maximum-average-pass-ratio
2113-find-the-kth-largest-integer-in-the-array
2429-design-a-food-rating-system
2585-delete-greatest-value-in-each-row
3678-design-task-manager

Merge Sort

0493-reverse-pairs
0948-sort-an-array

Bucket Sort

0948-sort-an-array

Radix Sort

0948-sort-an-array

Counting Sort

0948-sort-an-array

Binary Indexed Tree

0493-reverse-pairs

Segment Tree

0493-reverse-pairs
3790-fruits-into-baskets-ii

Memoization

0070-climbing-stairs

Combinatorics

0062-unique-paths
2324-find-triangular-sum-of-an-array
2605-count-anagrams

Rolling Hash

0187-repeated-dna-sequences

Hash Function

0187-repeated-dna-sequences

Prefix Sum

0209-minimum-size-subarray-sum
0303-range-sum-query-immutable
0713-subarray-product-less-than-k
1184-car-pooling
1206-corporate-flight-bookings
1538-maximum-points-you-can-obtain-from-cards
3639-zero-array-transformation-i
3643-zero-array-transformation-ii
3794-find-the-minimum-amount-of-time-to-brew-potions

Database

0175-combine-two-tables
0176-second-highest-salary
0197-rising-temperature
0570-managers-with-at-least-5-direct-reports
0584-find-customer-referee
1258-article-views-i
1317-monthly-transactions-i
1509-replace-employee-id-with-the-unique-identifier
1908-recyclable-and-low-fat-products
2087-confirmation-rate

Quickselect

0215-kth-largest-element-in-an-array
2113-find-the-kth-largest-integer-in-the-array

Enumeration

0204-count-primes
2170-count-number-of-maximum-bitwise-or-subsets
2337-remove-digit-from-number-to-maximize-result
2837-minimum-operations-to-make-the-integer-zero

Number Theory

0204-count-primes
3936-split-array-by-prime-indices

Brainteaser

0292-nim-game
2503-longest-subarray-with-maximum-bitwise-and
2837-minimum-operations-to-make-the-integer-zero
3462-vowels-game-in-a-string

Design

0297-serialize-and-deserialize-binary-tree
0303-range-sum-query-immutable
0937-online-stock-span
2429-design-a-food-rating-system
3678-design-task-manager

Game Theory

0292-nim-game
3462-vowels-game-in-a-string

Union Find

0128-longest-consecutive-sequence
1706-min-cost-to-connect-all-points

Graph

1706-min-cost-to-connect-all-points

Minimum Spanning Tree

1706-min-cost-to-connect-all-points

String Matching

0459-repeated-substring-pattern

Data Stream

0937-online-stock-span

Geometry

0830-largest-triangle-area