competitive_programming

String

0344-reverse-string
0409-longest-palindrome
0648-replace-words
1044-find-common-characters
3379-score-of-a-string

Two Pointers

0075-sort-colors
0344-reverse-string
0633-sum-of-square-numbers
0853-most-profit-assigning-work
3471-minimum-average-of-smallest-and-largest-elements

Hash Table

0041-first-missing-positive
0409-longest-palindrome
0648-replace-words
1016-subarray-sums-divisible-by-k
1044-find-common-characters
1217-relative-sort-array
2447-merge-similar-items

Greedy

0330-patching-array
0409-longest-palindrome
0502-ipo
0853-most-profit-assigning-work
1285-balance-a-binary-search-tree

Array

0041-first-missing-positive
0075-sort-colors
0330-patching-array
0502-ipo
0540-single-element-in-a-sorted-array
0648-replace-words
0853-most-profit-assigning-work
1016-subarray-sums-divisible-by-k
1044-find-common-characters
1137-height-checker
1138-grumpy-bookstore-owner
1217-relative-sort-array
1549-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit
2447-merge-similar-items
3471-minimum-average-of-smallest-and-largest-elements

Trie

0648-replace-words

Prefix Sum

1016-subarray-sums-divisible-by-k

Sorting

0075-sort-colors
0502-ipo
0853-most-profit-assigning-work
1137-height-checker
1217-relative-sort-array
2447-merge-similar-items
3471-minimum-average-of-smallest-and-largest-elements

Counting Sort

1137-height-checker
1217-relative-sort-array

Linked List

0838-design-linked-list

Design

0838-design-linked-list

Heap (Priority Queue)

0502-ipo
1549-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit

Math

0633-sum-of-square-numbers

Binary Search

0633-sum-of-square-numbers
0853-most-profit-assigning-work

Sliding Window

1138-grumpy-bookstore-owner
1549-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit

Queue

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

Ordered Set

1549-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit
2447-merge-similar-items

Monotonic Queue

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

Tree

1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree

Depth-First Search

1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree
2403-count-unreachable-pairs-of-nodes-in-an-undirected-graph

Binary Search Tree

0540-single-element-in-a-sorted-array
1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree

Binary Tree

1114-binary-search-tree-to-greater-sum-tree
1285-balance-a-binary-search-tree

Divide and Conquer

1285-balance-a-binary-search-tree

Breadth-First Search

2403-count-unreachable-pairs-of-nodes-in-an-undirected-graph

Union Find

2403-count-unreachable-pairs-of-nodes-in-an-undirected-graph

Graph

2403-count-unreachable-pairs-of-nodes-in-an-undirected-graph

LeetCode Topics

Depth-First Search

0113-path-sum-ii
0130-surrounded-regions
0145-binary-tree-postorder-traversal
0199-binary-tree-right-side-view
0207-course-schedule
0257-binary-tree-paths
0386-lexicographical-numbers
0684-redundant-connection
0685-redundant-connection-ii
0744-network-delay-time
0775-n-ary-tree-preorder-traversal
0776-n-ary-tree-postorder-traversal
0799-minimum-distance-between-bst-nodes
0803-cheapest-flights-within-k-stops
0984-most-stones-removed-with-same-row-or-column
1120-flower-planting-with-no-adjacent
1275-validate-binary-tree-nodes
1396-count-servers-that-communicate
1428-jump-game-iii
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1484-linked-list-in-binary-tree
1576-reorder-routes-to-make-all-paths-lead-to-the-city-zero
1653-number-of-good-leaf-nodes-pairs
1753-path-with-minimum-effort
2035-count-sub-islands
2213-find-all-people-with-secret
2217-step-by-step-directions-from-a-binary-tree-node-to-another
2403-count-unreachable-pairs-of-nodes-in-an-undirected-graph

Breadth-First Search

0130-surrounded-regions
0199-binary-tree-right-side-view
0207-course-schedule
0684-redundant-connection
0685-redundant-connection-ii
0744-network-delay-time
0764-n-ary-tree-level-order-traversal
0799-minimum-distance-between-bst-nodes
0803-cheapest-flights-within-k-stops
1120-flower-planting-with-no-adjacent
1275-validate-binary-tree-nodes
1396-count-servers-that-communicate
1428-jump-game-iii
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1484-linked-list-in-binary-tree
1576-reorder-routes-to-make-all-paths-lead-to-the-city-zero
1753-path-with-minimum-effort
1876-map-of-highest-peak
2035-count-sub-islands
2038-nearest-exit-from-entrance-in-maze
2213-find-all-people-with-secret
2403-count-unreachable-pairs-of-nodes-in-an-undirected-graph
3239-minimum-number-of-operations-to-make-x-and-y-equal

Graph

0207-course-schedule
0684-redundant-connection
0685-redundant-connection-ii
0744-network-delay-time
0803-cheapest-flights-within-k-stops
0984-most-stones-removed-with-same-row-or-column
1120-flower-planting-with-no-adjacent
1275-validate-binary-tree-nodes
1325-path-with-maximum-probability
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph
1456-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance
1576-reorder-routes-to-make-all-paths-lead-to-the-city-zero
1701-remove-max-number-of-edges-to-keep-graph-fully-traversable
2198-process-restricted-friend-requests
2213-find-all-people-with-secret
2403-count-unreachable-pairs-of-nodes-in-an-undirected-graph
3389-minimum-time-to-visit-disappearing-nodes

Topological Sort

0207-course-schedule
1431-all-ancestors-of-a-node-in-a-directed-acyclic-graph

Array

0001-two-sum
0004-median-of-two-sorted-arrays
0040-combination-sum-ii
0064-minimum-path-sum
0073-set-matrix-zeroes
0081-search-in-rotated-sorted-array-ii
0120-triangle
0130-surrounded-regions
0152-maximum-product-subarray
0153-find-minimum-in-rotated-sorted-array
0179-largest-number
0217-contains-duplicate
0313-super-ugly-number
0350-intersection-of-two-arrays-ii
0410-split-array-largest-sum
0540-single-element-in-a-sorted-array
0605-can-place-flowers
0624-maximum-distance-in-arrays
0729-my-calendar-i
0747-min-cost-climbing-stairs
0890-lemonade-change
0901-advantage-shuffle
0907-koko-eating-bananas
0926-find-and-replace-pattern
0966-binary-subarrays-with-sum
0991-array-of-doubled-pairs
1080-camelcase-matching
1272-invalid-transactions
1293-three-consecutive-odds
1325-path-with-maximum-probability
1331-path-with-maximum-gold
1333-sort-the-jumbled-numbers
1335-maximum-candies-allocated-to-k-children
1354-find-players-with-zero-or-one-losses
1396-count-servers-that-communicate
1428-jump-game-iii
1435-xor-queries-of-a-subarray
1458-sort-integers-by-the-number-of-1-bits
1496-lucky-numbers-in-a-matrix
1497-design-a-stack-with-increment-operation
1524-string-matching-in-an-array
1605-minimum-number-of-days-to-make-m-bouquets
1616-minimum-difference-between-largest-and-smallest-value-in-three-moves
1620-check-if-array-pairs-are-divisible-by-k
1646-kth-missing-positive-number
1675-magnetic-force-between-two-balls
1711-find-valid-matrix-given-row-and-column-sums
1753-path-with-minimum-effort
1786-count-the-number-of-consistent-strings
1814-jump-game-vi
1876-map-of-highest-peak
2006-find-the-student-that-will-replace-the-chalk
2035-count-sub-islands
2038-nearest-exit-from-entrance-in-maze
2054-the-number-of-the-smallest-unoccupied-chair
2155-find-missing-observations
2241-recover-the-original-array
2378-sender-with-largest-word-count
2502-sort-the-people
2503-longest-subarray-with-maximum-bitwise-and
2536-determine-if-two-events-have-conflict
2616-maximal-score-after-applying-k-operations
2695-find-score-of-an-array-after-marking-all-elements
2767-maximum-sum-with-exactly-k-elements
2794-maximum-number-of-moves-in-a-grid
2846-robot-collisions
2847-find-maximum-number-of-string-pairs
2855-maximum-number-of-jumps-to-reach-the-last-index
3193-maximum-strong-pair-xor-i
3291-find-if-array-can-be-sorted
3389-minimum-time-to-visit-disappearing-nodes
3501-delete-nodes-from-linked-list-present-in-array
3526-minimum-number-of-flips-to-make-binary-grid-palindromic-i
3528-reach-end-of-array-with-max-score

Binary Search

0004-median-of-two-sorted-arrays
0081-search-in-rotated-sorted-array-ii
0153-find-minimum-in-rotated-sorted-array
0350-intersection-of-two-arrays-ii
0410-split-array-largest-sum
0540-single-element-in-a-sorted-array
0729-my-calendar-i
0755-reach-a-number
0907-koko-eating-bananas
1321-get-equal-substrings-within-budget
1335-maximum-candies-allocated-to-k-children
1605-minimum-number-of-days-to-make-m-bouquets
1646-kth-missing-positive-number
1675-magnetic-force-between-two-balls
1753-path-with-minimum-effort
2006-find-the-student-that-will-replace-the-chalk

Sorting

0179-largest-number
0217-contains-duplicate
0350-intersection-of-two-arrays-ii
0807-custom-sort-string
0901-advantage-shuffle
0991-array-of-doubled-pairs
1272-invalid-transactions
1333-sort-the-jumbled-numbers
1354-find-players-with-zero-or-one-losses
1458-sort-integers-by-the-number-of-1-bits
1616-minimum-difference-between-largest-and-smallest-value-in-three-moves
1675-magnetic-force-between-two-balls
2213-find-all-people-with-secret
2241-recover-the-original-array
2502-sort-the-people
2695-find-score-of-an-array-after-marking-all-elements
2846-robot-collisions
3276-minimum-number-of-pushes-to-type-word-ii
3291-find-if-array-can-be-sorted

Union Find

0130-surrounded-regions
0684-redundant-connection
0685-redundant-connection-ii
0984-most-stones-removed-with-same-row-or-column
1275-validate-binary-tree-nodes
1396-count-servers-that-communicate
1701-remove-max-number-of-edges-to-keep-graph-fully-traversable
1753-path-with-minimum-effort
2035-count-sub-islands
2198-process-restricted-friend-requests
2213-find-all-people-with-secret
2403-count-unreachable-pairs-of-nodes-in-an-undirected-graph

Hash Table

0001-two-sum
0073-set-matrix-zeroes
0217-contains-duplicate
0264-ugly-number-ii
0350-intersection-of-two-arrays-ii
0355-design-twitter
0677-map-sum-pairs
0807-custom-sort-string
0920-uncommon-words-from-two-sentences
0926-find-and-replace-pattern
0966-binary-subarrays-with-sum
0984-most-stones-removed-with-same-row-or-column
0991-array-of-doubled-pairs
1272-invalid-transactions
1354-find-players-with-zero-or-one-losses
1473-find-the-longest-substring-containing-vowels-in-even-counts
1526-html-entity-parser
1620-check-if-array-pairs-are-divisible-by-k
1715-split-a-string-into-the-max-number-of-unique-substrings
1786-count-the-number-of-consistent-strings
1844-maximum-number-of-balls-in-a-box
2054-the-number-of-the-smallest-unoccupied-chair
2241-recover-the-original-array
2378-sender-with-largest-word-count
2502-sort-the-people
2695-find-score-of-an-array-after-marking-all-elements
2847-find-maximum-number-of-string-pairs
3193-maximum-strong-pair-xor-i
3276-minimum-number-of-pushes-to-type-word-ii
3501-delete-nodes-from-linked-list-present-in-array

Two Pointers

0028-find-the-index-of-the-first-occurrence-in-a-string
0350-intersection-of-two-arrays-ii
0901-advantage-shuffle
1080-camelcase-matching
2241-recover-the-original-array
3526-minimum-number-of-flips-to-make-binary-grid-palindromic-i

Linked List

0002-add-two-numbers
0109-convert-sorted-list-to-binary-search-tree
0355-design-twitter
0725-split-linked-list-in-parts
1484-linked-list-in-binary-tree
2182-find-the-minimum-and-maximum-number-of-nodes-between-critical-points
2299-merge-nodes-in-between-zeros
2903-insert-greatest-common-divisors-in-linked-list
3501-delete-nodes-from-linked-list-present-in-array

Math

0002-add-two-numbers
0096-unique-binary-search-trees
0264-ugly-number-ii
0313-super-ugly-number
0592-fraction-addition-and-subtraction
0755-reach-a-number
0767-prime-number-of-set-bits-in-binary-representation
1334-sum-of-numbers-with-units-digit-k
1630-count-odd-numbers-in-an-interval-range
1844-maximum-number-of-balls-in-a-box
2155-find-missing-observations
2238-a-number-after-a-double-reversal
2298-count-integers-with-even-digit-sum
2541-sum-of-number-and-its-reverse
2645-pass-the-pillow
2680-count-collisions-of-monkeys-on-a-polygon
2903-insert-greatest-common-divisors-in-linked-list

Simulation

0592-fraction-addition-and-subtraction
2006-find-the-student-that-will-replace-the-chalk
2076-sum-of-digits-of-string-after-convert
2155-find-missing-observations
2298-count-integers-with-even-digit-sum
2299-merge-nodes-in-between-zeros
2645-pass-the-pillow
2695-find-score-of-an-array-after-marking-all-elements
2846-robot-collisions
2847-find-maximum-number-of-string-pairs
3426-minimum-number-of-chairs-in-a-waiting-room

Tree

0096-unique-binary-search-trees
0109-convert-sorted-list-to-binary-search-tree
0113-path-sum-ii
0145-binary-tree-postorder-traversal
0199-binary-tree-right-side-view
0257-binary-tree-paths
0764-n-ary-tree-level-order-traversal
0775-n-ary-tree-preorder-traversal
0776-n-ary-tree-postorder-traversal
0799-minimum-distance-between-bst-nodes
1275-validate-binary-tree-nodes
1484-linked-list-in-binary-tree
1653-number-of-good-leaf-nodes-pairs
2217-step-by-step-directions-from-a-binary-tree-node-to-another

Binary Tree

0096-unique-binary-search-trees
0109-convert-sorted-list-to-binary-search-tree
0113-path-sum-ii
0145-binary-tree-postorder-traversal
0199-binary-tree-right-side-view
0257-binary-tree-paths
0799-minimum-distance-between-bst-nodes
1275-validate-binary-tree-nodes
1484-linked-list-in-binary-tree
1653-number-of-good-leaf-nodes-pairs
2217-step-by-step-directions-from-a-binary-tree-node-to-another

Greedy

0179-largest-number
0410-split-array-largest-sum
0605-can-place-flowers
0624-maximum-distance-in-arrays
0890-lemonade-change
0901-advantage-shuffle
0991-array-of-doubled-pairs
1026-string-without-aaa-or-bbb
1334-sum-of-numbers-with-units-digit-k
1616-minimum-difference-between-largest-and-smallest-value-in-three-moves
1711-find-valid-matrix-given-row-and-column-sums
2616-maximal-score-after-applying-k-operations
2767-maximum-sum-with-exactly-k-elements
3276-minimum-number-of-pushes-to-type-word-ii
3528-reach-end-of-array-with-max-score

Matrix

0064-minimum-path-sum
0073-set-matrix-zeroes
0130-surrounded-regions
1331-path-with-maximum-gold
1396-count-servers-that-communicate
1496-lucky-numbers-in-a-matrix
1711-find-valid-matrix-given-row-and-column-sums
1753-path-with-minimum-effort
1876-map-of-highest-peak
2035-count-sub-islands
2038-nearest-exit-from-entrance-in-maze
2794-maximum-number-of-moves-in-a-grid
3526-minimum-number-of-flips-to-make-binary-grid-palindromic-i

String

0028-find-the-index-of-the-first-occurrence-in-a-string
0091-decode-ways
0179-largest-number
0257-binary-tree-paths
0592-fraction-addition-and-subtraction
0677-map-sum-pairs
0807-custom-sort-string
0857-positions-of-large-groups
0920-uncommon-words-from-two-sentences
0926-find-and-replace-pattern
1026-string-without-aaa-or-bbb
1078-remove-outermost-parentheses
1080-camelcase-matching
1272-invalid-transactions
1320-remove-all-adjacent-duplicates-in-string-ii
1321-get-equal-substrings-within-budget
1473-find-the-longest-substring-containing-vowels-in-even-counts
1524-string-matching-in-an-array
1526-html-entity-parser
1715-split-a-string-into-the-max-number-of-unique-substrings
1786-count-the-number-of-consistent-strings
2001-jump-game-vii
2076-sum-of-digits-of-string-after-convert
2217-step-by-step-directions-from-a-binary-tree-node-to-another
2243-check-if-all-as-appears-before-all-bs
2378-sender-with-largest-word-count
2502-sort-the-people
2536-determine-if-two-events-have-conflict
2580-circular-sentence
2847-find-maximum-number-of-string-pairs
3276-minimum-number-of-pushes-to-type-word-ii
3426-minimum-number-of-chairs-in-a-waiting-room

Dynamic Programming

0064-minimum-path-sum
0091-decode-ways
0096-unique-binary-search-trees
0120-triangle
0152-maximum-product-subarray
0264-ugly-number-ii
0313-super-ugly-number
0410-split-array-largest-sum
0747-min-cost-climbing-stairs
0803-cheapest-flights-within-k-stops
1263-number-of-dice-rolls-with-target-sum
1334-sum-of-numbers-with-units-digit-k
1456-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance
1814-jump-game-vi
2001-jump-game-vii
2794-maximum-number-of-moves-in-a-grid
2855-maximum-number-of-jumps-to-reach-the-last-index
3239-minimum-number-of-operations-to-make-x-and-y-equal

Heap (Priority Queue)

0264-ugly-number-ii
0355-design-twitter
0744-network-delay-time
0803-cheapest-flights-within-k-stops
1325-path-with-maximum-probability
1753-path-with-minimum-effort
1814-jump-game-vi
2054-the-number-of-the-smallest-unoccupied-chair
2616-maximal-score-after-applying-k-operations
2695-find-score-of-an-array-after-marking-all-elements
3389-minimum-time-to-visit-disappearing-nodes

Backtracking

0040-combination-sum-ii
0113-path-sum-ii
0257-binary-tree-paths
1331-path-with-maximum-gold
1715-split-a-string-into-the-max-number-of-unique-substrings

Recursion

0002-add-two-numbers
2680-count-collisions-of-monkeys-on-a-polygon

Counting

0920-uncommon-words-from-two-sentences
1354-find-players-with-zero-or-one-losses
1396-count-servers-that-communicate
1458-sort-integers-by-the-number-of-1-bits
1620-check-if-array-pairs-are-divisible-by-k
1786-count-the-number-of-consistent-strings
1844-maximum-number-of-balls-in-a-box
2378-sender-with-largest-word-count
3276-minimum-number-of-pushes-to-type-word-ii

Stack

0145-binary-tree-postorder-traversal
0775-n-ary-tree-preorder-traversal
0776-n-ary-tree-postorder-traversal
1078-remove-outermost-parentheses
1320-remove-all-adjacent-duplicates-in-string-ii
1497-design-a-stack-with-increment-operation
2846-robot-collisions

Shortest Path

0744-network-delay-time
0803-cheapest-flights-within-k-stops
1325-path-with-maximum-probability
1456-find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance
3389-minimum-time-to-visit-disappearing-nodes

Prefix Sum

0410-split-array-largest-sum
0966-binary-subarrays-with-sum
1321-get-equal-substrings-within-budget
1435-xor-queries-of-a-subarray
1473-find-the-longest-substring-containing-vowels-in-even-counts
2001-jump-game-vii
2006-find-the-student-that-will-replace-the-chalk

Sliding Window

0966-binary-subarrays-with-sum
1321-get-equal-substrings-within-budget
2001-jump-game-vii
3193-maximum-strong-pair-xor-i

Divide and Conquer

0004-median-of-two-sorted-arrays
0109-convert-sorted-list-to-binary-search-tree
0191-number-of-1-bits

Binary Search Tree

0096-unique-binary-search-trees
0109-convert-sorted-list-to-binary-search-tree
0799-minimum-distance-between-bst-nodes

Design

0355-design-twitter
0677-map-sum-pairs
0729-my-calendar-i
1497-design-a-stack-with-increment-operation

Trie

0386-lexicographical-numbers
0677-map-sum-pairs
1080-camelcase-matching
3193-maximum-strong-pair-xor-i

Enumeration

1334-sum-of-numbers-with-units-digit-k
2241-recover-the-original-array
2541-sum-of-number-and-its-reverse

Bit Manipulation

0191-number-of-1-bits
0767-prime-number-of-set-bits-in-binary-representation
1435-xor-queries-of-a-subarray
1458-sort-integers-by-the-number-of-1-bits
1473-find-the-longest-substring-containing-vowels-in-even-counts
1786-count-the-number-of-consistent-strings
2323-minimum-bit-flips-to-convert-number
2503-longest-subarray-with-maximum-bitwise-and
3193-maximum-strong-pair-xor-i
3291-find-if-array-can-be-sorted

Number Theory

2903-insert-greatest-common-divisors-in-linked-list

Brainteaser

2503-longest-subarray-with-maximum-bitwise-and

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string
1080-camelcase-matching
1524-string-matching-in-an-array

Queue

1814-jump-game-vi

Monotonic Queue

1814-jump-game-vi

Memoization

3239-minimum-number-of-operations-to-make-x-and-y-equal

Segment Tree

0729-my-calendar-i

Ordered Set

0729-my-calendar-i