LeetCode Topics

Array

0011-container-with-most-water
0027-remove-element
0036-valid-sudoku
0040-combination-sum-ii
0066-plus-one
0084-largest-rectangle-in-histogram
0085-maximal-rectangle
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0120-triangle
0150-evaluate-reverse-polish-notation
0198-house-robber
0274-h-index
0407-trapping-rain-water-ii
0523-continuous-subarray-sum
0739-daily-temperatures
0744-find-smallest-letter-greater-than-target
0794-swim-in-rising-water
0840-magic-squares-in-grid
0907-sum-of-subarray-minimums
0944-delete-columns-to-make-sorted
0955-delete-columns-to-make-sorted-ii
0961-n-repeated-element-in-size-2n-array
1018-binary-prefix-divisible-by-5
1110-delete-nodes-and-return-forest
1200-minimum-absolute-difference
1262-greatest-sum-divisible-by-three
1266-minimum-time-visiting-all-points
1351-count-negative-numbers-in-a-sorted-matrix
1356-sort-integers-by-the-number-of-1-bits
1390-four-divisors
1426-find-n-unique-integers-sum-up-to-zero
1458-max-dot-product-of-two-subsequences
1548-check-if-all-1s-are-at-least-length-k-places-away
1586-longest-subarray-of-1s-after-deleting-one-element
1612-avoid-flood-in-the-city
1700-minimum-time-to-make-rope-colorful
1877-minimize-maximum-pair-sum-in-array
1895-largest-magic-square
1970-last-day-where-you-can-still-cross
1975-maximum-matrix-sum
1984-minimum-difference-between-highest-and-lowest-of-k-scores
2110-number-of-smooth-descent-periods-of-a-stock
2137-final-value-of-variable-after-performing-operations
2141-maximum-running-time-of-n-computers
2274-keep-multiplying-found-values-by-two
2324-find-triangular-sum-of-an-array
2392-successful-pairs-of-spells-and-potions
2402-meeting-rooms-iii
2432-number-of-zero-filled-subarrays
2435-paths-in-matrix-whose-sum-is-divisible-by-k
2625-increment-submatrices-by-one
2661-smallest-missing-non-negative-integer-after-operations
2770-maximum-number-of-jumps-to-reach-the-last-index
2943-maximize-area-of-square-hole-in-grid
2975-maximum-square-area-by-removing-fences-from-a-field
3010-divide-an-array-into-subarrays-with-minimum-cost-i
3013-divide-an-array-into-subarrays-with-minimum-cost-ii
3047-find-the-largest-area-of-square-inside-two-rectangles
3074-apple-redistribution-into-boxes
3075-maximize-happiness-of-selected-children
3190-find-minimum-operations-to-make-all-elements-divisible-by-three
3251-maximum-area-of-longest-diagonal-rectangle
3314-construct-the-minimum-bitwise-array-i
3315-construct-the-minimum-bitwise-array-ii
3379-transformed-array
3381-maximum-subarray-sum-with-length-divisible-by-k
3432-count-partitions-with-even-sum-difference
3433-count-mentions-per-user
3453-separate-squares-i
3454-separate-squares-ii
3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii
3512-minimum-operations-to-make-array-sum-divisible-by-k
3531-count-covered-buildings
3562-maximum-profit-from-trading-stocks-with-discounts
3573-best-time-to-buy-and-sell-stock-v
3577-count-the-number-of-computer-unlocking-permutations
3578-count-partitions-with-max-min-difference-at-most-k
3581-the-two-sneaky-numbers-of-digitville
3583-count-special-triplets
3592-find-x-sum-of-all-k-long-subarrays-ii
3606-coupon-code-validator
3610-find-x-sum-of-all-k-long-subarrays-i
3620-maximum-number-of-distinct-elements-after-operations
3623-count-number-of-trapezoids-i
3625-count-number-of-trapezoids-ii
3634-minimum-removals-to-balance-array
3637-trionic-array-i
3640-trionic-array-ii
3651-minimum-cost-path-with-teleportations
3652-best-time-to-buy-and-sell-stock-using-strategy
3719-longest-balanced-subarray-i
3721-longest-balanced-subarray-ii

Backtracking

0040-combination-sum-ii
0113-path-sum-ii
0756-pyramid-transition-matrix

Math

0009-palindrome-number
0066-plus-one
0067-add-binary
0150-evaluate-reverse-polish-notation
0224-basic-calculator
0231-power-of-two
0279-perfect-squares
0342-power-of-four
0523-continuous-subarray-sum
0762-prime-number-of-set-bits-in-binary-representation
0840-magic-squares-in-grid
0900-reordered-power-of-2
1015-smallest-integer-divisible-by-k
1266-minimum-time-visiting-all-points
1390-four-divisors
1426-find-n-unique-integers-sum-up-to-zero
1523-count-odd-numbers-in-an-interval-range
1642-water-bottles
1680-concatenation-of-consecutive-binary-numbers
1817-calculate-money-in-leetcode-bank
1925-count-square-sum-triples
2110-number-of-smooth-descent-periods-of-a-stock
2147-number-of-ways-to-divide-a-long-corridor
2288-count-operations-to-obtain-zero
2324-find-triangular-sum-of-an-array
2396-strictly-palindromic-number
2432-number-of-zero-filled-subarrays
2661-smallest-missing-non-negative-integer-after-operations
3047-find-the-largest-area-of-square-inside-two-rectangles
3190-find-minimum-operations-to-make-all-elements-divisible-by-three
3279-alice-and-bob-playing-flower-game
3336-water-bottles-ii
3432-count-partitions-with-even-sum-difference
3433-count-mentions-per-user
3462-vowels-game-in-a-string
3512-minimum-operations-to-make-array-sum-divisible-by-k
3577-count-the-number-of-computer-unlocking-permutations
3581-the-two-sneaky-numbers-of-digitville
3623-count-number-of-trapezoids-i
3625-count-number-of-trapezoids-ii
3676-smallest-number-with-all-set-bits

Bit Manipulation

0067-add-binary
0190-reverse-bits
0222-count-complete-tree-nodes
0231-power-of-two
0342-power-of-four
0693-binary-number-with-alternating-bits
0756-pyramid-transition-matrix
0762-prime-number-of-set-bits-in-binary-representation
0868-binary-gap
1018-binary-prefix-divisible-by-5
1356-sort-integers-by-the-number-of-1-bits
1404-number-of-steps-to-reduce-a-number-in-binary-representation-to-one
1461-check-if-a-string-contains-all-binary-codes-of-size-k
1680-concatenation-of-consecutive-binary-numbers
2059-unique-length-3-palindromic-subsequences
3314-construct-the-minimum-bitwise-array-i
3315-construct-the-minimum-bitwise-array-ii
3676-smallest-number-with-all-set-bits

Recursion

0224-basic-calculator
0231-power-of-two
0342-power-of-four

Hash Table

0003-longest-substring-without-repeating-characters
0036-valid-sudoku
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0290-word-pattern
0395-longest-substring-with-at-least-k-repeating-characters
0523-continuous-subarray-sum
0652-find-duplicate-subtrees
0756-pyramid-transition-matrix
0840-magic-squares-in-grid
0900-reordered-power-of-2
0961-n-repeated-element-in-size-2n-array
1015-smallest-integer-divisible-by-k
1110-delete-nodes-and-return-forest
1123-lowest-common-ancestor-of-deepest-leaves
1461-check-if-a-string-contains-all-binary-codes-of-size-k
1612-avoid-flood-in-the-city
2059-unique-length-3-palindromic-subsequences
2274-keep-multiplying-found-values-by-two
2402-meeting-rooms-iii
2620-find-consecutive-integers-from-a-data-stream
2661-smallest-missing-non-negative-integer-after-operations
2975-maximum-square-area-by-removing-fences-from-a-field
3013-divide-an-array-into-subarrays-with-minimum-cost-ii
3381-maximum-subarray-sum-with-length-divisible-by-k
3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii
3531-count-covered-buildings
3581-the-two-sneaky-numbers-of-digitville
3583-count-special-triplets
3592-find-x-sum-of-all-k-long-subarrays-ii
3606-coupon-code-validator
3610-find-x-sum-of-all-k-long-subarrays-i
3623-count-number-of-trapezoids-i
3625-count-number-of-trapezoids-ii
3713-longest-balanced-substring-i
3714-longest-balanced-substring-ii
3719-longest-balanced-subarray-i
3721-longest-balanced-subarray-ii
3872-find-most-frequent-vowel-and-consonant

Sorting

0274-h-index
0761-special-binary-string
0900-reordered-power-of-2
1200-minimum-absolute-difference
1262-greatest-sum-divisible-by-three
1356-sort-integers-by-the-number-of-1-bits
1877-minimize-maximum-pair-sum-in-array
1984-minimum-difference-between-highest-and-lowest-of-k-scores
2141-maximum-running-time-of-n-computers
2274-keep-multiplying-found-values-by-two
2392-successful-pairs-of-spells-and-potions
2402-meeting-rooms-iii
2943-maximize-area-of-square-hole-in-grid
3010-divide-an-array-into-subarrays-with-minimum-cost-i
3074-apple-redistribution-into-boxes
3075-maximize-happiness-of-selected-children
3433-count-mentions-per-user
3531-count-covered-buildings
3606-coupon-code-validator
3620-maximum-number-of-distinct-elements-after-operations
3634-minimum-removals-to-balance-array

Counting

0900-reordered-power-of-2
1356-sort-integers-by-the-number-of-1-bits
2620-find-consecutive-integers-from-a-data-stream
3583-count-special-triplets
3713-longest-balanced-substring-i
3872-find-most-frequent-vowel-and-consonant
4090-minimum-string-length-after-balanced-removals

Enumeration

0900-reordered-power-of-2
1925-count-square-sum-triples
2975-maximum-square-area-by-removing-fences-from-a-field
3010-divide-an-array-into-subarrays-with-minimum-cost-i
3713-longest-balanced-substring-i

Dynamic Programming

0072-edit-distance
0085-maximal-rectangle
0120-triangle
0124-binary-tree-maximum-path-sum
0198-house-robber
0279-perfect-squares
0712-minimum-ascii-delete-sum-for-two-strings
0799-champagne-tower
0907-sum-of-subarray-minimums
1262-greatest-sum-divisible-by-three
1411-number-of-ways-to-paint-n-3-grid
1458-max-dot-product-of-two-subsequences
1586-longest-subarray-of-1s-after-deleting-one-element
1653-minimum-deletions-to-make-string-balanced
1700-minimum-time-to-make-rope-colorful
2110-number-of-smooth-descent-periods-of-a-stock
2147-number-of-ways-to-divide-a-long-corridor
2435-paths-in-matrix-whose-sum-is-divisible-by-k
2770-maximum-number-of-jumps-to-reach-the-last-index
3562-maximum-profit-from-trading-stocks-with-discounts
3573-best-time-to-buy-and-sell-stock-v
3578-count-partitions-with-max-min-difference-at-most-k
3640-trionic-array-ii
3651-minimum-cost-path-with-teleportations

Breadth-First Search

0100-same-tree
0112-path-sum
0199-binary-tree-right-side-view
0279-perfect-squares
0407-trapping-rain-water-ii
0623-add-one-row-to-tree
0794-swim-in-rising-water
0958-check-completeness-of-a-binary-tree
1123-lowest-common-ancestor-of-deepest-leaves
1161-maximum-level-sum-of-a-binary-tree
1970-last-day-where-you-can-still-cross

String

0003-longest-substring-without-repeating-characters
0067-add-binary
0072-edit-distance
0165-compare-version-numbers
0224-basic-calculator
0290-word-pattern
0395-longest-substring-with-at-least-k-repeating-characters
0696-count-binary-substrings
0712-minimum-ascii-delete-sum-for-two-strings
0756-pyramid-transition-matrix
0761-special-binary-string
0944-delete-columns-to-make-sorted
0955-delete-columns-to-make-sorted-ii
1047-remove-all-adjacent-duplicates-in-string
1404-number-of-steps-to-reduce-a-number-in-binary-representation-to-one
1461-check-if-a-string-contains-all-binary-codes-of-size-k
1653-minimum-deletions-to-make-string-balanced
1689-partitioning-into-minimum-number-of-deci-binary-numbers
1700-minimum-time-to-make-rope-colorful
2059-unique-length-3-palindromic-subsequences
2137-final-value-of-variable-after-performing-operations
2147-number-of-ways-to-divide-a-long-corridor
2211-count-collisions-on-a-road
2483-minimum-penalty-for-a-shop
3462-vowels-game-in-a-string
3606-coupon-code-validator
3713-longest-balanced-substring-i
3714-longest-balanced-substring-ii
3872-find-most-frequent-vowel-and-consonant
4090-minimum-string-length-after-balanced-removals

Design

0232-implement-queue-using-stacks
0901-online-stock-span
2620-find-consecutive-integers-from-a-data-stream

Queue

0232-implement-queue-using-stacks
2620-find-consecutive-integers-from-a-data-stream
3578-count-partitions-with-max-min-difference-at-most-k

Data Stream

0901-online-stock-span
2620-find-consecutive-integers-from-a-data-stream

Sliding Window

0003-longest-substring-without-repeating-characters
0395-longest-substring-with-at-least-k-repeating-characters
1586-longest-subarray-of-1s-after-deleting-one-element
1984-minimum-difference-between-highest-and-lowest-of-k-scores
3013-divide-an-array-into-subarrays-with-minimum-cost-ii
3578-count-partitions-with-max-min-difference-at-most-k
3592-find-x-sum-of-all-k-long-subarrays-ii
3610-find-x-sum-of-all-k-long-subarrays-i
3634-minimum-removals-to-balance-array
3652-best-time-to-buy-and-sell-stock-using-strategy

Matrix

0036-valid-sudoku
0085-maximal-rectangle
0407-trapping-rain-water-ii
0794-swim-in-rising-water
0840-magic-squares-in-grid
1351-count-negative-numbers-in-a-sorted-matrix
1895-largest-magic-square
1970-last-day-where-you-can-still-cross
1975-maximum-matrix-sum
2435-paths-in-matrix-whose-sum-is-divisible-by-k
2625-increment-submatrices-by-one
3651-minimum-cost-path-with-teleportations

Brainteaser

2396-strictly-palindromic-number
3462-vowels-game-in-a-string
3577-count-the-number-of-computer-unlocking-permutations

Game Theory

3462-vowels-game-in-a-string

Two Pointers

0011-container-with-most-water
0027-remove-element
0165-compare-version-numbers
0696-count-binary-substrings
1877-minimize-maximum-pair-sum-in-array
2392-successful-pairs-of-spells-and-potions
2396-strictly-palindromic-number

Simulation

0067-add-binary
1404-number-of-steps-to-reduce-a-number-in-binary-representation-to-one
1642-water-bottles
1680-concatenation-of-consecutive-binary-numbers
2137-final-value-of-variable-after-performing-operations
2211-count-collisions-on-a-road
2274-keep-multiplying-found-values-by-two
2288-count-operations-to-obtain-zero
2324-find-triangular-sum-of-an-array
2402-meeting-rooms-iii
3336-water-bottles-ii
3379-transformed-array
3433-count-mentions-per-user
3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii

Combinatorics

2324-find-triangular-sum-of-an-array
3577-count-the-number-of-computer-unlocking-permutations

Heap (Priority Queue)

0023-merge-k-sorted-lists
0407-trapping-rain-water-ii
0794-swim-in-rising-water
1612-avoid-flood-in-the-city
2402-meeting-rooms-iii
3013-divide-an-array-into-subarrays-with-minimum-cost-ii
3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii
3592-find-x-sum-of-all-k-long-subarrays-ii
3610-find-x-sum-of-all-k-long-subarrays-i
3650-minimum-cost-path-with-edge-reversals

Greedy

0011-container-with-most-water
0955-delete-columns-to-make-sorted-ii
1262-greatest-sum-divisible-by-three
1382-balance-a-binary-search-tree
1612-avoid-flood-in-the-city
1689-partitioning-into-minimum-number-of-deci-binary-numbers
1700-minimum-time-to-make-rope-colorful
1877-minimize-maximum-pair-sum-in-array
1975-maximum-matrix-sum
2141-maximum-running-time-of-n-computers
2661-smallest-missing-non-negative-integer-after-operations
3074-apple-redistribution-into-boxes
3075-maximize-happiness-of-selected-children
3620-maximum-number-of-distinct-elements-after-operations

Linked List

0023-merge-k-sorted-lists
3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii

Divide and Conquer

0023-merge-k-sorted-lists
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0190-reverse-bits
0395-longest-substring-with-at-least-k-repeating-characters
0761-special-binary-string
1382-balance-a-binary-search-tree
3719-longest-balanced-subarray-i
3721-longest-balanced-subarray-ii

Merge Sort

0023-merge-k-sorted-lists

Binary Search

0222-count-complete-tree-nodes
0744-find-smallest-letter-greater-than-target
0794-swim-in-rising-water
1351-count-negative-numbers-in-a-sorted-matrix
1612-avoid-flood-in-the-city
1970-last-day-where-you-can-still-cross
2141-maximum-running-time-of-n-computers
2392-successful-pairs-of-spells-and-potions
3453-separate-squares-i
3454-separate-squares-ii

Depth-First Search

0100-same-tree
0110-balanced-binary-tree
0112-path-sum
0113-path-sum-ii
0124-binary-tree-maximum-path-sum
0199-binary-tree-right-side-view
0543-diameter-of-binary-tree
0623-add-one-row-to-tree
0652-find-duplicate-subtrees
0794-swim-in-rising-water
0814-binary-tree-pruning
0872-leaf-similar-trees
1026-maximum-difference-between-node-and-ancestor
1110-delete-nodes-and-return-forest
1123-lowest-common-ancestor-of-deepest-leaves
1161-maximum-level-sum-of-a-binary-tree
1339-maximum-product-of-splitted-binary-tree
1382-balance-a-binary-search-tree
1970-last-day-where-you-can-still-cross
2872-maximum-number-of-k-divisible-components
3562-maximum-profit-from-trading-stocks-with-discounts

Union Find

0794-swim-in-rising-water
1970-last-day-where-you-can-still-cross

Counting Sort

0274-h-index

Prefix Sum

0523-continuous-subarray-sum
1895-largest-magic-square
2059-unique-length-3-palindromic-subsequences
2483-minimum-penalty-for-a-shop
2625-increment-submatrices-by-one
3381-maximum-subarray-sum-with-length-divisible-by-k
3432-count-partitions-with-even-sum-difference
3578-count-partitions-with-max-min-difference-at-most-k
3652-best-time-to-buy-and-sell-stock-using-strategy
3714-longest-balanced-substring-ii
3719-longest-balanced-subarray-i
3721-longest-balanced-subarray-ii

Stack

0084-largest-rectangle-in-histogram
0085-maximal-rectangle
0150-evaluate-reverse-polish-notation
0224-basic-calculator
0232-implement-queue-using-stacks
0739-daily-temperatures
0901-online-stock-span
0907-sum-of-subarray-minimums
1047-remove-all-adjacent-duplicates-in-string
1653-minimum-deletions-to-make-string-balanced
2211-count-collisions-on-a-road
4090-minimum-string-length-after-balanced-removals

Tree

0100-same-tree
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0110-balanced-binary-tree
0112-path-sum
0113-path-sum-ii
0124-binary-tree-maximum-path-sum
0199-binary-tree-right-side-view
0222-count-complete-tree-nodes
0543-diameter-of-binary-tree
0623-add-one-row-to-tree
0652-find-duplicate-subtrees
0814-binary-tree-pruning
0872-leaf-similar-trees
0958-check-completeness-of-a-binary-tree
1026-maximum-difference-between-node-and-ancestor
1110-delete-nodes-and-return-forest
1123-lowest-common-ancestor-of-deepest-leaves
1161-maximum-level-sum-of-a-binary-tree
1339-maximum-product-of-splitted-binary-tree
1382-balance-a-binary-search-tree
2872-maximum-number-of-k-divisible-components
3562-maximum-profit-from-trading-stocks-with-discounts

Geometry

1266-minimum-time-visiting-all-points
3047-find-the-largest-area-of-square-inside-two-rectangles
3623-count-number-of-trapezoids-i
3625-count-number-of-trapezoids-ii

Monotonic Queue

3578-count-partitions-with-max-min-difference-at-most-k

Monotonic Stack

0084-largest-rectangle-in-histogram
0085-maximal-rectangle
0739-daily-temperatures
0901-online-stock-span
0907-sum-of-subarray-minimums

Binary Tree

0100-same-tree
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0110-balanced-binary-tree
0112-path-sum
0113-path-sum-ii
0124-binary-tree-maximum-path-sum
0199-binary-tree-right-side-view
0222-count-complete-tree-nodes
0543-diameter-of-binary-tree
0623-add-one-row-to-tree
0652-find-duplicate-subtrees
0814-binary-tree-pruning
0872-leaf-similar-trees
0958-check-completeness-of-a-binary-tree
1026-maximum-difference-between-node-and-ancestor
1110-delete-nodes-and-return-forest
1123-lowest-common-ancestor-of-deepest-leaves
1161-maximum-level-sum-of-a-binary-tree
1339-maximum-product-of-splitted-binary-tree
1382-balance-a-binary-search-tree

Segment Tree

3454-separate-squares-ii
3719-longest-balanced-subarray-i
3721-longest-balanced-subarray-ii

Line Sweep

3454-separate-squares-ii

Doubly-Linked List

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

Graph Theory

3650-minimum-cost-path-with-edge-reversals

Shortest Path

3650-minimum-cost-path-with-edge-reversals

Binary Search Tree

1382-balance-a-binary-search-tree

Rolling Hash

1461-check-if-a-string-contains-all-binary-codes-of-size-k

Hash Function

1461-check-if-a-string-contains-all-binary-codes-of-size-k

Database

0175-combine-two-tables
0176-second-highest-salary
0177-nth-highest-salary
0178-rank-scores
0181-employees-earning-more-than-their-managers
0182-duplicate-emails
0184-department-highest-salary