Leetcode_quesion

LeetCode Topics

Array

0014-longest-common-prefix
0034-find-first-and-last-position-of-element-in-sorted-array
0036-valid-sudoku
0039-combination-sum
0046-permutations
0054-spiral-matrix
0056-merge-intervals
0059-spiral-matrix-ii
0078-subsets
0081-search-in-rotated-sorted-array-ii
0108-convert-sorted-array-to-binary-search-tree
0119-pascals-triangle-ii
0121-best-time-to-buy-and-sell-stock
0130-surrounded-regions
0136-single-number
0137-single-number-ii
0150-evaluate-reverse-polish-notation
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0200-number-of-islands
0215-kth-largest-element-in-an-array
0268-missing-number
0275-h-index-ii
0329-longest-increasing-path-in-a-matrix
0347-top-k-frequent-elements
0442-find-all-duplicates-in-an-array
0448-find-all-numbers-disappeared-in-an-array
0452-minimum-number-of-arrows-to-burst-balloons
0456-132-pattern
0475-heaters
0485-max-consecutive-ones
0496-next-greater-element-i
0525-contiguous-array
0542-01-matrix
0560-subarray-sum-equals-k
0605-can-place-flowers
0628-maximum-product-of-three-numbers
0636-exclusive-time-of-functions
0645-set-mismatch
0665-non-decreasing-array
0690-employee-importance
0705-design-hashset
0733-flood-fill
0739-daily-temperatures
0792-binary-search
0825-max-increase-to-keep-city-skyline
0859-design-circular-deque
0877-stone-game
0890-lemonade-change
0943-sum-of-subarray-minimums
0960-delete-columns-to-make-sorted-iii
0961-n-repeated-element-in-size-2n-array
0987-reveal-cards-in-increasing-order
1002-maximum-width-ramp
1018-largest-perimeter-triangle
1036-rotting-oranges
1039-find-the-town-judge
1044-find-common-characters
1056-capacity-to-ship-packages-within-d-days
1095-two-city-scheduling
1217-minimum-cost-to-move-chips-to-the-same-position
1231-replace-elements-with-greatest-element-on-right-side
1242-matrix-block-sum
1248-count-number-of-nice-subarrays
1293-three-consecutive-odds
1305-number-of-visible-people-in-a-queue
1335-maximum-candies-allocated-to-k-children
1351-count-negative-numbers-in-a-sorted-matrix
1356-sort-integers-by-the-number-of-1-bits
1365-how-many-numbers-are-smaller-than-the-current-number
1441-build-an-array-with-stack-operations
1464-reduce-array-size-to-the-half
1470-shuffle-the-array
1477-product-of-the-last-k-numbers
1502-can-make-arithmetic-progression-from-sequence
1549-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit
1590-make-sum-divisible-by-p
1635-number-of-good-pairs
1675-magnetic-force-between-two-balls
1720-crawler-log-folder
1762-furthest-building-you-can-reach
1767-design-front-middle-back-queue
1776-minimum-operations-to-reduce-x-to-zero
1783-ways-to-make-a-fair-array
1787-sum-of-absolute-differences-in-a-sorted-array
1849-maximum-absolute-sum-of-any-subarray
1876-map-of-highest-peak
1929-concatenation-of-array
1951-find-the-winner-of-the-circular-game
2054-two-best-non-overlapping-events
2110-number-of-smooth-descent-periods-of-a-stock
2113-find-the-kth-largest-integer-in-the-array
2220-find-all-possible-recipes-from-given-supplies
2373-largest-local-values-in-a-matrix
2465-shifting-letters-ii
2533-bitwise-xor-of-all-pairings
2708-maximum-strength-of-a-group
2737-row-with-maximum-ones
2768-number-of-black-blocks
2975-maximum-square-area-by-removing-fences-from-a-field
3432-count-partitions-with-even-sum-difference
3433-count-mentions-per-user
3527-find-the-most-common-response
3531-count-covered-buildings
3573-best-time-to-buy-and-sell-stock-v
3577-count-the-number-of-computer-unlocking-permutations
3583-count-special-triplets
3606-coupon-code-validator
3634-minimum-removals-to-balance-array
3637-trionic-array-i
3640-trionic-array-ii
3643-zero-array-transformation-ii
3652-best-time-to-buy-and-sell-stock-using-strategy
3719-longest-balanced-subarray-i

Hash Table

0003-longest-substring-without-repeating-characters
0036-valid-sudoku
0141-linked-list-cycle
0142-linked-list-cycle-ii
0146-lru-cache
0187-repeated-dna-sequences
0205-isomorphic-strings
0268-missing-number
0347-top-k-frequent-elements
0442-find-all-duplicates-in-an-array
0448-find-all-numbers-disappeared-in-an-array
0496-next-greater-element-i
0525-contiguous-array
0560-subarray-sum-equals-k
0645-set-mismatch
0690-employee-importance
0705-design-hashset
0961-n-repeated-element-in-size-2n-array
1039-find-the-town-judge
1044-find-common-characters
1248-count-number-of-nice-subarrays
1365-how-many-numbers-are-smaller-than-the-current-number
1464-reduce-array-size-to-the-half
1590-make-sum-divisible-by-p
1635-number-of-good-pairs
1776-minimum-operations-to-reduce-x-to-zero
1873-longest-nice-substring
2220-find-all-possible-recipes-from-given-supplies
2620-find-consecutive-integers-from-a-data-stream
2768-number-of-black-blocks
2975-maximum-square-area-by-removing-fences-from-a-field
3527-find-the-most-common-response
3531-count-covered-buildings
3583-count-special-triplets
3606-coupon-code-validator
3714-longest-balanced-substring-ii
3719-longest-balanced-subarray-i

Prefix Sum

0525-contiguous-array
0560-subarray-sum-equals-k
1242-matrix-block-sum
1248-count-number-of-nice-subarrays
1477-product-of-the-last-k-numbers
1590-make-sum-divisible-by-p
1776-minimum-operations-to-reduce-x-to-zero
1783-ways-to-make-a-fair-array
1787-sum-of-absolute-differences-in-a-sorted-array
2325-number-of-ways-to-select-buildings
2465-shifting-letters-ii
3432-count-partitions-with-even-sum-difference
3643-zero-array-transformation-ii
3652-best-time-to-buy-and-sell-stock-using-strategy
3714-longest-balanced-substring-ii
3719-longest-balanced-subarray-i

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0023-merge-k-sorted-lists
0025-reverse-nodes-in-k-group
0083-remove-duplicates-from-sorted-list
0086-partition-list
0092-reverse-linked-list-ii
0141-linked-list-cycle
0142-linked-list-cycle-ii
0146-lru-cache
0203-remove-linked-list-elements
0206-reverse-linked-list
0234-palindrome-linked-list
0237-delete-node-in-a-linked-list
0705-design-hashset
0838-design-linked-list
0859-design-circular-deque
0908-middle-of-the-linked-list
1767-design-front-middle-back-queue

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0025-reverse-nodes-in-k-group
0050-powx-n
0203-remove-linked-list-elements
0206-reverse-linked-list
0234-palindrome-linked-list
0342-power-of-four
1667-find-kth-bit-in-nth-binary-string
1951-find-the-winner-of-the-circular-game

String

0003-longest-substring-without-repeating-characters
0014-longest-common-prefix
0020-valid-parentheses
0067-add-binary
0071-simplify-path
0171-excel-sheet-column-number
0187-repeated-dna-sequences
0205-isomorphic-strings
0696-count-binary-substrings
0761-special-binary-string
0874-backspace-string-compare
0886-score-of-parentheses
0960-delete-columns-to-make-sorted-iii
1021-remove-outermost-parentheses
1044-find-common-characters
1341-split-a-string-in-balanced-strings
1404-number-of-steps-to-reduce-a-number-in-binary-representation-to-one
1653-minimum-deletions-to-make-string-balanced
1667-find-kth-bit-in-nth-binary-string
1720-crawler-log-folder
1873-longest-nice-substring
2113-find-the-kth-largest-integer-in-the-array
2211-count-collisions-on-a-road
2220-find-all-possible-recipes-from-given-supplies
2325-number-of-ways-to-select-buildings
2465-shifting-letters-ii
2470-removing-stars-from-a-string
3055-maximum-odd-binary-number
3527-find-the-most-common-response
3606-coupon-code-validator
3714-longest-balanced-substring-ii

Two Pointers

0019-remove-nth-node-from-end-of-list
0086-partition-list
0141-linked-list-cycle
0142-linked-list-cycle-ii
0234-palindrome-linked-list
0475-heaters
0696-count-binary-substrings
0874-backspace-string-compare
0908-middle-of-the-linked-list
1002-maximum-width-ramp

Stack

0020-valid-parentheses
0071-simplify-path
0094-binary-tree-inorder-traversal
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0150-evaluate-reverse-polish-notation
0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0234-palindrome-linked-list
0456-132-pattern
0496-next-greater-element-i
0636-exclusive-time-of-functions
0739-daily-temperatures
0874-backspace-string-compare
0886-score-of-parentheses
0943-sum-of-subarray-minimums
1002-maximum-width-ramp
1021-remove-outermost-parentheses
1305-number-of-visible-people-in-a-queue
1441-build-an-array-with-stack-operations
1653-minimum-deletions-to-make-string-balanced
1720-crawler-log-folder
2211-count-collisions-on-a-road
2470-removing-stars-from-a-string

Design

0146-lru-cache
0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0705-design-hashset
0789-kth-largest-element-in-a-stream
0838-design-linked-list
0859-design-circular-deque
0969-number-of-recent-calls
1477-product-of-the-last-k-numbers
1767-design-front-middle-back-queue
1955-seat-reservation-manager
2620-find-consecutive-integers-from-a-data-stream

Doubly-Linked List

0146-lru-cache

Dynamic Programming

0070-climbing-stairs
0119-pascals-triangle-ii
0121-best-time-to-buy-and-sell-stock
0279-perfect-squares
0329-longest-increasing-path-in-a-matrix
0343-integer-break
0542-01-matrix
0799-champagne-tower
0877-stone-game
0943-sum-of-subarray-minimums
0960-delete-columns-to-make-sorted-iii
1653-minimum-deletions-to-make-string-balanced
1849-maximum-absolute-sum-of-any-subarray
2054-two-best-non-overlapping-events
2110-number-of-smooth-descent-periods-of-a-stock
2325-number-of-ways-to-select-buildings
2708-maximum-strength-of-a-group
3573-best-time-to-buy-and-sell-stock-v
3640-trionic-array-ii

Math

0002-add-two-numbers
0029-divide-two-integers
0050-powx-n
0067-add-binary
0070-climbing-stairs
0089-gray-code
0150-evaluate-reverse-polish-notation
0171-excel-sheet-column-number
0172-factorial-trailing-zeroes
0263-ugly-number
0268-missing-number
0279-perfect-squares
0342-power-of-four
0343-integer-break
0628-maximum-product-of-three-numbers
0754-reach-a-number
0762-prime-number-of-set-bits-in-binary-representation
0877-stone-game
1018-largest-perimeter-triangle
1217-minimum-cost-to-move-chips-to-the-same-position
1248-count-number-of-nice-subarrays
1303-minimum-moves-to-reach-target-score
1477-product-of-the-last-k-numbers
1523-count-odd-numbers-in-an-interval-range
1635-number-of-good-pairs
1787-sum-of-absolute-differences-in-a-sorted-array
1925-count-square-sum-triples
1951-find-the-winner-of-the-circular-game
2110-number-of-smooth-descent-periods-of-a-stock
3055-maximum-odd-binary-number
3432-count-partitions-with-even-sum-difference
3433-count-mentions-per-user
3577-count-the-number-of-computer-unlocking-permutations

Matrix

0036-valid-sudoku
0054-spiral-matrix
0059-spiral-matrix-ii
0130-surrounded-regions
0200-number-of-islands
0329-longest-increasing-path-in-a-matrix
0542-01-matrix
0733-flood-fill
0825-max-increase-to-keep-city-skyline
1036-rotting-oranges
1242-matrix-block-sum
1351-count-negative-numbers-in-a-sorted-matrix
1876-map-of-highest-peak
2373-largest-local-values-in-a-matrix
2737-row-with-maximum-ones

Queue

0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0859-design-circular-deque
0969-number-of-recent-calls
0987-reveal-cards-in-increasing-order
1549-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit
1767-design-front-middle-back-queue
1951-find-the-winner-of-the-circular-game
2620-find-consecutive-integers-from-a-data-stream

Data Stream

0789-kth-largest-element-in-a-stream
0969-number-of-recent-calls
1477-product-of-the-last-k-numbers
1767-design-front-middle-back-queue
2620-find-consecutive-integers-from-a-data-stream

Greedy

0452-minimum-number-of-arrows-to-burst-balloons
0605-can-place-flowers
0825-max-increase-to-keep-city-skyline
0890-lemonade-change
1018-largest-perimeter-triangle
1095-two-city-scheduling
1217-minimum-cost-to-move-chips-to-the-same-position
1285-balance-a-binary-search-tree
1303-minimum-moves-to-reach-target-score
1341-split-a-string-in-balanced-strings
1382-balance-a-binary-search-tree
1464-reduce-array-size-to-the-half
1762-furthest-building-you-can-reach
2708-maximum-strength-of-a-group
3055-maximum-odd-binary-number

Counting

0347-top-k-frequent-elements
1341-split-a-string-in-balanced-strings
1356-sort-integers-by-the-number-of-1-bits
1635-number-of-good-pairs
2620-find-consecutive-integers-from-a-data-stream
3527-find-the-most-common-response
3583-count-special-triplets

Sorting

0056-merge-intervals
0215-kth-largest-element-in-an-array
0268-missing-number
0347-top-k-frequent-elements
0452-minimum-number-of-arrows-to-burst-balloons
0475-heaters
0628-maximum-product-of-three-numbers
0645-set-mismatch
0761-special-binary-string
0987-reveal-cards-in-increasing-order
1018-largest-perimeter-triangle
1095-two-city-scheduling
1356-sort-integers-by-the-number-of-1-bits
1365-how-many-numbers-are-smaller-than-the-current-number
1464-reduce-array-size-to-the-half
1502-can-make-arithmetic-progression-from-sequence
1675-magnetic-force-between-two-balls
2054-two-best-non-overlapping-events
2113-find-the-kth-largest-integer-in-the-array
2708-maximum-strength-of-a-group
3433-count-mentions-per-user
3531-count-covered-buildings
3606-coupon-code-validator
3634-minimum-removals-to-balance-array

Simulation

0054-spiral-matrix
0059-spiral-matrix-ii
0067-add-binary
0874-backspace-string-compare
0987-reveal-cards-in-increasing-order
1404-number-of-steps-to-reduce-a-number-in-binary-representation-to-one
1441-build-an-array-with-stack-operations
1667-find-kth-bit-in-nth-binary-string
1929-concatenation-of-array
1951-find-the-winner-of-the-circular-game
2211-count-collisions-on-a-road
2470-removing-stars-from-a-string
3433-count-mentions-per-user

Monotonic Stack

0456-132-pattern
0496-next-greater-element-i
0739-daily-temperatures
0943-sum-of-subarray-minimums
1002-maximum-width-ramp
1305-number-of-visible-people-in-a-queue

Heap (Priority Queue)

0023-merge-k-sorted-lists
0215-kth-largest-element-in-an-array
0347-top-k-frequent-elements
0789-kth-largest-element-in-a-stream
1464-reduce-array-size-to-the-half
1549-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit
1762-furthest-building-you-can-reach
1955-seat-reservation-manager
2054-two-best-non-overlapping-events
2113-find-the-kth-largest-integer-in-the-array

Binary Search

0034-find-first-and-last-position-of-element-in-sorted-array
0081-search-in-rotated-sorted-array-ii
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0268-missing-number
0275-h-index-ii
0278-first-bad-version
0456-132-pattern
0475-heaters
0754-reach-a-number
0792-binary-search
1056-capacity-to-ship-packages-within-d-days
1335-maximum-candies-allocated-to-k-children
1351-count-negative-numbers-in-a-sorted-matrix
1675-magnetic-force-between-two-balls
1776-minimum-operations-to-reduce-x-to-zero
2054-two-best-non-overlapping-events
3643-zero-array-transformation-ii

Ordered Set

0456-132-pattern
1549-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit

Sliding Window

0003-longest-substring-without-repeating-characters
0187-repeated-dna-sequences
1248-count-number-of-nice-subarrays
1549-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit
1776-minimum-operations-to-reduce-x-to-zero
1873-longest-nice-substring
3634-minimum-removals-to-balance-array
3652-best-time-to-buy-and-sell-stock-using-strategy

Monotonic Queue

1549-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit

Bit Manipulation

0029-divide-two-integers
0067-add-binary
0078-subsets
0089-gray-code
0136-single-number
0137-single-number-ii
0187-repeated-dna-sequences
0190-reverse-bits
0191-number-of-1-bits
0268-missing-number
0342-power-of-four
0401-binary-watch
0645-set-mismatch
0693-binary-number-with-alternating-bits
0762-prime-number-of-set-bits-in-binary-representation
1356-sort-integers-by-the-number-of-1-bits
1404-number-of-steps-to-reduce-a-number-in-binary-representation-to-one
1873-longest-nice-substring
2533-bitwise-xor-of-all-pairings
2708-maximum-strength-of-a-group

Tree

0094-binary-tree-inorder-traversal
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
0129-sum-root-to-leaf-numbers
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0515-find-largest-value-in-each-tree-row
0690-employee-importance
0783-search-in-a-binary-search-tree
0789-kth-largest-element-in-a-stream
1005-univalued-binary-tree
1092-maximum-difference-between-node-and-ancestor
1285-balance-a-binary-search-tree
1382-balance-a-binary-search-tree
2493-reverse-odd-levels-of-binary-tree

Depth-First Search

0094-binary-tree-inorder-traversal
0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0129-sum-root-to-leaf-numbers
0130-surrounded-regions
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0200-number-of-islands
0210-course-schedule-ii
0329-longest-increasing-path-in-a-matrix
0515-find-largest-value-in-each-tree-row
0684-redundant-connection
0690-employee-importance
0733-flood-fill
0801-is-graph-bipartite
0820-find-eventual-safe-states
0871-keys-and-rooms
1005-univalued-binary-tree
1092-maximum-difference-between-node-and-ancestor
1285-balance-a-binary-search-tree
1382-balance-a-binary-search-tree
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1558-course-schedule-iv
2493-reverse-odd-levels-of-binary-tree

Binary Tree

0094-binary-tree-inorder-traversal
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
0129-sum-root-to-leaf-numbers
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0515-find-largest-value-in-each-tree-row
0783-search-in-a-binary-search-tree
0789-kth-largest-element-in-a-stream
1005-univalued-binary-tree
1092-maximum-difference-between-node-and-ancestor
1285-balance-a-binary-search-tree
1382-balance-a-binary-search-tree
2493-reverse-odd-levels-of-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
0130-surrounded-regions
0200-number-of-islands
0210-course-schedule-ii
0279-perfect-squares
0329-longest-increasing-path-in-a-matrix
0515-find-largest-value-in-each-tree-row
0542-01-matrix
0684-redundant-connection
0690-employee-importance
0733-flood-fill
0801-is-graph-bipartite
0820-find-eventual-safe-states
0871-keys-and-rooms
1005-univalued-binary-tree
1036-rotting-oranges
1229-shortest-path-with-alternating-colors
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1558-course-schedule-iv
1876-map-of-highest-peak
2493-reverse-odd-levels-of-binary-tree

Binary Search Tree

0108-convert-sorted-array-to-binary-search-tree
0783-search-in-a-binary-search-tree
0789-kth-largest-element-in-a-stream
1285-balance-a-binary-search-tree
1382-balance-a-binary-search-tree

Backtracking

0039-combination-sum
0046-permutations
0078-subsets
0089-gray-code
0401-binary-watch
2708-maximum-strength-of-a-group

Divide and Conquer

0023-merge-k-sorted-lists
0108-convert-sorted-array-to-binary-search-tree
0190-reverse-bits
0191-number-of-1-bits
0215-kth-largest-element-in-an-array
0347-top-k-frequent-elements
0761-special-binary-string
1285-balance-a-binary-search-tree
1382-balance-a-binary-search-tree
1873-longest-nice-substring
2113-find-the-kth-largest-integer-in-the-array
3719-longest-balanced-subarray-i

Interactive

0278-first-bad-version

Bucket Sort

0347-top-k-frequent-elements

Quickselect

0215-kth-largest-element-in-an-array
0347-top-k-frequent-elements
2113-find-the-kth-largest-integer-in-the-array

Union Find

0130-surrounded-regions
0200-number-of-islands
0684-redundant-connection
0801-is-graph-bipartite

Graph

0210-course-schedule-ii
0329-longest-increasing-path-in-a-matrix
0684-redundant-connection
0801-is-graph-bipartite
0820-find-eventual-safe-states
0871-keys-and-rooms
1039-find-the-town-judge
1229-shortest-path-with-alternating-colors
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1558-course-schedule-iv
2220-find-all-possible-recipes-from-given-supplies

Topological Sort

0210-course-schedule-ii
0329-longest-increasing-path-in-a-matrix
0820-find-eventual-safe-states
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1558-course-schedule-iv
2220-find-all-possible-recipes-from-given-supplies

Merge Sort

0023-merge-k-sorted-lists

Memoization

0070-climbing-stairs
0329-longest-increasing-path-in-a-matrix

Brainteaser

2533-bitwise-xor-of-all-pairings
3577-count-the-number-of-computer-unlocking-permutations

Game Theory

0877-stone-game

Trie

0014-longest-common-prefix

Enumeration

1925-count-square-sum-triples
2708-maximum-strength-of-a-group
2768-number-of-black-blocks
2975-maximum-square-area-by-removing-fences-from-a-field

Rolling Hash

0187-repeated-dna-sequences

Hash Function

0187-repeated-dna-sequences
0705-design-hashset

Combinatorics

3577-count-the-number-of-computer-unlocking-permutations

Counting Sort

1365-how-many-numbers-are-smaller-than-the-current-number

Segment Tree

3719-longest-balanced-subarray-i