Leetcode-questions

LeetCode Topics

Array

0001-two-sum
0011-container-with-most-water
0018-4sum
0042-trapping-rain-water
0048-rotate-image
0049-group-anagrams
0053-maximum-subarray
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0128-longest-consecutive-sequence
0130-surrounded-regions
0153-find-minimum-in-rotated-sorted-array
0200-number-of-islands
0219-contains-duplicate-ii
0229-majority-element-ii
0523-continuous-subarray-sum
0525-contiguous-array
0542-01-matrix
0560-subarray-sum-equals-k
0628-maximum-product-of-three-numbers
0695-max-area-of-island
0705-design-hashset
0713-subarray-product-less-than-k
0733-flood-fill
0832-flipping-an-image
0845-longest-mountain-in-array
0848-shifting-letters
0867-transpose-matrix
0974-subarray-sums-divisible-by-k
0992-subarrays-with-k-different-integers
0994-rotting-oranges
0997-find-the-town-judge
1004-max-consecutive-ones-iii
1020-number-of-enclaves
1260-shift-2d-grid
1299-replace-elements-with-greatest-element-on-right-side
1331-rank-transform-of-an-array
1346-check-if-n-and-its-double-exist
1394-find-lucky-integer-in-an-array
1464-maximum-product-of-two-elements-in-an-array
1475-final-prices-with-a-special-discount-in-a-shop
1631-path-with-minimum-effort
1732-find-the-highest-altitude
1748-sum-of-unique-elements
1833-maximum-ice-cream-bars
1855-maximum-distance-between-a-pair-of-values
1967-number-of-strings-that-appear-as-substrings-in-word
1979-find-greatest-common-divisor-of-array
2078-two-furthest-houses-with-different-colors
2161-partition-array-according-to-given-pivot
2302-count-subarrays-with-score-less-than-k
2410-maximum-matching-of-players-with-trainers
2540-minimum-common-value
2553-separate-the-digits-in-an-array
2574-left-and-right-sum-differences
2679-sum-in-a-matrix

Two Pointers

0011-container-with-most-water
0018-4sum
0042-trapping-rain-water
0061-rotate-list
0082-remove-duplicates-from-sorted-list-ii
0202-happy-number
0653-two-sum-iv-input-is-a-bst
0832-flipping-an-image
0845-longest-mountain-in-array
1346-check-if-n-and-its-double-exist
1855-maximum-distance-between-a-pair-of-values
2000-reverse-prefix-of-word
2095-delete-the-middle-node-of-a-linked-list
2161-partition-array-according-to-given-pivot
2410-maximum-matching-of-players-with-trainers
2540-minimum-common-value

Binary Search

0153-find-minimum-in-rotated-sorted-array
0367-valid-perfect-square
0441-arranging-coins
0713-subarray-product-less-than-k
1004-max-consecutive-ones-iii
1346-check-if-n-and-its-double-exist
1631-path-with-minimum-effort
1855-maximum-distance-between-a-pair-of-values
2302-count-subarrays-with-score-less-than-k
2540-minimum-common-value

Math

0007-reverse-integer
0048-rotate-image
0202-happy-number
0367-valid-perfect-square
0441-arranging-coins
0445-add-two-numbers-ii
0523-continuous-subarray-sum
0628-maximum-product-of-three-numbers
1486-xor-operation-in-an-array
1979-find-greatest-common-divisor-of-array
3014-minimum-number-of-pushes-to-type-word-i
3536-maximum-product-of-two-digits
3658-gcd-of-odd-and-even-sums
3754-concatenate-non-zero-digits-and-multiply-by-sum-i
3783-mirror-distance-of-an-integer

Greedy

0011-container-with-most-water
0409-longest-palindrome
0678-valid-parenthesis-string
1081-smallest-subsequence-of-distinct-characters
1833-maximum-ice-cream-bars
2078-two-furthest-houses-with-different-colors
2410-maximum-matching-of-players-with-trainers
3014-minimum-number-of-pushes-to-type-word-i
3016-minimum-number-of-pushes-to-type-word-ii

Stack

0042-trapping-rain-water
0445-add-two-numbers-ii
0678-valid-parenthesis-string
0897-increasing-order-search-tree
1081-smallest-subsequence-of-distinct-characters
1475-final-prices-with-a-special-discount-in-a-shop
2000-reverse-prefix-of-word
2390-removing-stars-from-a-string

Tree

0102-binary-tree-level-order-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0111-minimum-depth-of-binary-tree
0112-path-sum
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0257-binary-tree-paths
0404-sum-of-left-leaves
0450-delete-node-in-a-bst
0513-find-bottom-left-tree-value
0653-two-sum-iv-input-is-a-bst
0701-insert-into-a-binary-search-tree
0897-increasing-order-search-tree
1373-maximum-sum-bst-in-binary-tree

Depth-First Search

0111-minimum-depth-of-binary-tree
0112-path-sum
0130-surrounded-regions
0200-number-of-islands
0207-course-schedule
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0257-binary-tree-paths
0404-sum-of-left-leaves
0513-find-bottom-left-tree-value
0547-number-of-provinces
0653-two-sum-iv-input-is-a-bst
0695-max-area-of-island
0733-flood-fill
0743-network-delay-time
0785-is-graph-bipartite
0787-cheapest-flights-within-k-stops
0802-find-eventual-safe-states
0897-increasing-order-search-tree
1020-number-of-enclaves
1319-number-of-operations-to-make-network-connected
1373-maximum-sum-bst-in-binary-tree
1631-path-with-minimum-effort

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
0653-two-sum-iv-input-is-a-bst
0701-insert-into-a-binary-search-tree
0897-increasing-order-search-tree
1373-maximum-sum-bst-in-binary-tree

Binary Tree

0102-binary-tree-level-order-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0111-minimum-depth-of-binary-tree
0112-path-sum
0230-kth-smallest-element-in-a-bst
0235-lowest-common-ancestor-of-a-binary-search-tree
0257-binary-tree-paths
0404-sum-of-left-leaves
0450-delete-node-in-a-bst
0513-find-bottom-left-tree-value
0653-two-sum-iv-input-is-a-bst
0701-insert-into-a-binary-search-tree
0897-increasing-order-search-tree
1373-maximum-sum-bst-in-binary-tree

Linked List

0061-rotate-list
0082-remove-duplicates-from-sorted-list-ii
0083-remove-duplicates-from-sorted-list
0445-add-two-numbers-ii
0705-design-hashset
2095-delete-the-middle-node-of-a-linked-list

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0049-group-anagrams
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0127-word-ladder
0128-longest-consecutive-sequence
0187-repeated-dna-sequences
0202-happy-number
0219-contains-duplicate-ii
0229-majority-element-ii
0409-longest-palindrome
0438-find-all-anagrams-in-a-string
0523-continuous-subarray-sum
0525-contiguous-array
0560-subarray-sum-equals-k
0653-two-sum-iv-input-is-a-bst
0705-design-hashset
0974-subarray-sums-divisible-by-k
0992-subarrays-with-k-different-integers
0997-find-the-town-judge
1189-maximum-number-of-balloons
1331-rank-transform-of-an-array
1346-check-if-n-and-its-double-exist
1358-number-of-substrings-containing-all-three-characters
1394-find-lucky-integer-in-an-array
1748-sum-of-unique-elements
2540-minimum-common-value
3016-minimum-number-of-pushes-to-type-word-ii

Design

0705-design-hashset

Hash Function

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

String

0003-longest-substring-without-repeating-characters
0006-zigzag-conversion
0049-group-anagrams
0127-word-ladder
0187-repeated-dna-sequences
0257-binary-tree-paths
0409-longest-palindrome
0438-find-all-anagrams-in-a-string
0678-valid-parenthesis-string
0686-repeated-string-match
0796-rotate-string
0848-shifting-letters
1081-smallest-subsequence-of-distinct-characters
1189-maximum-number-of-balloons
1358-number-of-substrings-containing-all-three-characters
1967-number-of-strings-that-appear-as-substrings-in-word
2000-reverse-prefix-of-word
2390-removing-stars-from-a-string
3014-minimum-number-of-pushes-to-type-word-i
3016-minimum-number-of-pushes-to-type-word-ii
3517-smallest-palindromic-rearrangement-i
3612-process-string-with-special-operations-i

Backtracking

0257-binary-tree-paths

Breadth-First Search

0102-binary-tree-level-order-traversal
0111-minimum-depth-of-binary-tree
0112-path-sum
0127-word-ladder
0130-surrounded-regions
0200-number-of-islands
0207-course-schedule
0404-sum-of-left-leaves
0513-find-bottom-left-tree-value
0542-01-matrix
0547-number-of-provinces
0653-two-sum-iv-input-is-a-bst
0695-max-area-of-island
0733-flood-fill
0743-network-delay-time
0785-is-graph-bipartite
0787-cheapest-flights-within-k-stops
0802-find-eventual-safe-states
0994-rotting-oranges
1020-number-of-enclaves
1319-number-of-operations-to-make-network-connected
1631-path-with-minimum-effort

Counting

0229-majority-element-ii
0992-subarrays-with-k-different-integers
1189-maximum-number-of-balloons
1394-find-lucky-integer-in-an-array
1748-sum-of-unique-elements
3016-minimum-number-of-pushes-to-type-word-ii

Divide and Conquer

0053-maximum-subarray
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0190-reverse-bits

Bit Manipulation

0187-repeated-dna-sequences
0190-reverse-bits
0476-number-complement
0832-flipping-an-image
1486-xor-operation-in-an-array

Simulation

0832-flipping-an-image
0867-transpose-matrix
1260-shift-2d-grid
2161-partition-array-according-to-given-pivot
2390-removing-stars-from-a-string
2553-separate-the-digits-in-an-array
2679-sum-in-a-matrix
3612-process-string-with-special-operations-i

String Matching

0686-repeated-string-match
0796-rotate-string

Matrix

0048-rotate-image
0130-surrounded-regions
0200-number-of-islands
0542-01-matrix
0695-max-area-of-island
0733-flood-fill
0832-flipping-an-image
0867-transpose-matrix
0994-rotting-oranges
1020-number-of-enclaves
1260-shift-2d-grid
1631-path-with-minimum-effort
2679-sum-in-a-matrix

Sliding Window

0003-longest-substring-without-repeating-characters
0187-repeated-dna-sequences
0219-contains-duplicate-ii
0438-find-all-anagrams-in-a-string
0713-subarray-product-less-than-k
0992-subarrays-with-k-different-integers
1004-max-consecutive-ones-iii
1358-number-of-substrings-containing-all-three-characters
2302-count-subarrays-with-score-less-than-k

Prefix Sum

0523-continuous-subarray-sum
0525-contiguous-array
0560-subarray-sum-equals-k
0713-subarray-product-less-than-k
0848-shifting-letters
0974-subarray-sums-divisible-by-k
1004-max-consecutive-ones-iii
1732-find-the-highest-altitude
2302-count-subarrays-with-score-less-than-k
2574-left-and-right-sum-differences

Sorting

0018-4sum
0049-group-anagrams
0229-majority-element-ii
0628-maximum-product-of-three-numbers
1331-rank-transform-of-an-array
1346-check-if-n-and-its-double-exist
1464-maximum-product-of-two-elements-in-an-array
1833-maximum-ice-cream-bars
2410-maximum-matching-of-players-with-trainers
2679-sum-in-a-matrix
3016-minimum-number-of-pushes-to-type-word-ii
3517-smallest-palindromic-rearrangement-i
3536-maximum-product-of-two-digits

Counting Sort

1833-maximum-ice-cream-bars
3517-smallest-palindromic-rearrangement-i

Monotonic Stack

0042-trapping-rain-water
1081-smallest-subsequence-of-distinct-characters
1475-final-prices-with-a-special-discount-in-a-shop

Dynamic Programming

0042-trapping-rain-water
0053-maximum-subarray
0542-01-matrix
0678-valid-parenthesis-string
0787-cheapest-flights-within-k-stops
0845-longest-mountain-in-array
1373-maximum-sum-bst-in-binary-tree
1976-number-of-ways-to-arrive-at-destination

Union-Find

0128-longest-consecutive-sequence
0130-surrounded-regions
0200-number-of-islands
0547-number-of-provinces
0695-max-area-of-island
0785-is-graph-bipartite
1020-number-of-enclaves
1319-number-of-operations-to-make-network-connected
1631-path-with-minimum-effort

Graph Theory

0207-course-schedule
0547-number-of-provinces
0743-network-delay-time
0785-is-graph-bipartite
0787-cheapest-flights-within-k-stops
0802-find-eventual-safe-states
0997-find-the-town-judge
1319-number-of-operations-to-make-network-connected
1976-number-of-ways-to-arrive-at-destination

Enumeration

0845-longest-mountain-in-array

Topological Sort

0207-course-schedule
0802-find-eventual-safe-states
1976-number-of-ways-to-arrive-at-destination

Heap (Priority Queue)

0743-network-delay-time
0787-cheapest-flights-within-k-stops
1464-maximum-product-of-two-elements-in-an-array
1631-path-with-minimum-effort
2679-sum-in-a-matrix

Number Theory

1979-find-greatest-common-divisor-of-array
3658-gcd-of-odd-and-even-sums

Shortest Path

0743-network-delay-time
0787-cheapest-flights-within-k-stops
1976-number-of-ways-to-arrive-at-destination

Rolling Hash

0187-repeated-dna-sequences