leetcode-dsa

Collection of LeetCode questions to ace the coding interview! - Created using LeetHub

LeetCode Topics

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0014-longest-common-prefix
0028-find-the-index-of-the-first-occurrence-in-a-string
0038-count-and-say
0125-valid-palindrome
0127-word-ladder
0151-reverse-words-in-a-string
0187-repeated-dna-sequences
0208-implement-trie-prefix-tree
0214-shortest-palindrome
0344-reverse-string
0647-palindromic-substrings
0686-repeated-string-match
0768-partition-labels
0812-rotate-string
0868-push-dominoes
0878-shifting-letters
0952-word-subsets
1093-recover-a-tree-from-preorder-traversal
1122-longest-duplicate-substring
1160-letter-tile-possibilities
1170-shortest-common-supersequence
1244-distinct-echo-substrings
1460-number-of-substrings-containing-all-three-characters
1502-construct-k-palindrome-strings
1508-longest-happy-prefix
1516-the-k-th-lexicographical-string-of-all-happy-strings-of-length-n
1524-string-matching-in-an-array
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1915-check-if-one-string-swap-can-make-strings-equal
2021-remove-all-occurrences-of-a-substring
2059-unique-length-3-palindromic-subsequences
2107-find-unique-binary-string
2186-count-vowel-substrings-of-a-string
2220-find-all-possible-recipes-from-given-supplies
2221-check-if-a-parentheses-string-can-be-valid
2292-counting-words-with-a-given-prefix
2326-sum-of-scores-of-built-strings
2456-construct-smallest-number-from-di-string
2463-minimum-recolors-to-get-k-consecutive-black-blocks
2465-shifting-letters-ii
3243-count-the-number-of-powerful-integers
3296-minimum-time-to-revert-word-to-initial-state-ii
3309-count-prefix-and-suffix-pairs-i
3329-find-the-length-of-the-longest-common-prefix
3447-clear-digits
3455-minimum-length-of-string-after-operations
3569-count-of-substrings-containing-every-vowel-and-k-consonants-ii
3634-find-mirror-score-of-a-string
3637-count-number-of-balanced-permutations
3684-substring-matching-pattern

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string
0214-shortest-palindrome
0686-repeated-string-match
0812-rotate-string
1508-longest-happy-prefix
1524-string-matching-in-an-array
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
2292-counting-words-with-a-given-prefix
2326-sum-of-scores-of-built-strings
3296-minimum-time-to-revert-word-to-initial-state-ii
3309-count-prefix-and-suffix-pairs-i
3684-substring-matching-pattern

Two Pointers

0005-longest-palindromic-substring
0028-find-the-index-of-the-first-occurrence-in-a-string
0125-valid-palindrome
0151-reverse-words-in-a-string
0344-reverse-string
0647-palindromic-substrings
0768-partition-labels
0868-push-dominoes
1566-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence
2588-maximum-number-of-points-from-grid-queries
2699-count-the-number-of-fair-pairs

Array

0001-two-sum
0056-merge-intervals
0057-insert-interval
0064-minimum-path-sum
0121-best-time-to-buy-and-sell-stock
0152-maximum-product-subarray
0153-find-minimum-in-rotated-sorted-array
0215-kth-largest-element-in-an-array
0307-range-sum-query-mutable
0329-longest-increasing-path-in-a-matrix
0368-largest-divisible-subset
0407-trapping-rain-water-ii
0416-partition-equal-subset-sum
0421-maximum-xor-of-two-numbers-in-an-array
0560-subarray-sum-equals-k
0741-cherry-pickup
0747-min-cost-climbing-stairs
0794-swim-in-rising-water
0797-rabbits-in-forest
0854-making-a-large-island
0878-shifting-letters
0902-minimum-number-of-refueling-stops
0905-length-of-longest-fibonacci-subsequence
0925-construct-binary-tree-from-preorder-and-postorder-traversal
0940-fruit-into-baskets
0952-word-subsets
1049-minimum-domino-rotations-for-equal-row
1184-car-pooling
1227-number-of-equivalent-domino-pairs
1234-number-of-paths-with-max-score
1293-three-consecutive-odds
1294-range-frequency-queries
1335-maximum-candies-allocated-to-k-children
1364-tuple-with-same-product
1396-count-servers-that-communicate
1414-shortest-path-in-a-grid-with-obstacles-elimination
1421-find-numbers-with-even-number-of-digits
1477-product-of-the-last-k-numbers
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1524-string-matching-in-an-array
1631-number-of-sub-arrays-with-odd-sum
1656-count-good-triplets
1819-construct-the-lexicographically-largest-valid-sequence
1849-maximum-absolute-sum-of-any-subarray
1876-map-of-highest-peak
1878-check-if-array-is-sorted-and-rotated
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1927-maximum-ascending-subarray-sum
1993-sum-of-all-subset-xor-totals
2048-build-array-from-permutation
2094-remove-stones-to-minimize-the-total
2107-find-unique-binary-string
2145-grid-game
2160-minimum-operations-to-make-a-uni-value-grid
2180-maximum-number-of-tasks-you-can-assign
2215-finding-3-digit-even-numbers
2220-find-all-possible-recipes-from-given-supplies
2249-count-the-hidden-sequences
2262-solving-questions-with-brainpower
2277-count-equal-and-divisible-pairs-in-an-array
2280-count-good-triplets-in-an-array
2292-counting-words-with-a-given-prefix
2308-divide-array-into-equal-pairs
2310-minimum-operations-to-halve-array-sum
2358-number-of-ways-to-split-array
2362-minimum-rounds-to-complete-all-tasks
2394-count-subarrays-with-score-less-than-k
2409-number-of-increasing-paths-in-a-grid
2448-count-number-of-bad-pairs
2465-shifting-letters-ii
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2478-longest-nice-subarray
2527-count-subarrays-with-fixed-bounds
2533-bitwise-xor-of-all-pairings
2564-most-profitable-path-in-a-tree
2588-maximum-number-of-points-from-grid-queries
2591-frog-jump-ii
2614-maximum-count-of-positive-integer-and-negative-integer
2626-count-the-number-of-good-subarrays
2665-minimum-time-to-repair-cars
2681-put-marbles-in-bags
2685-first-completely-painted-row-or-column
2690-house-robber-iv
2696-the-number-of-beautiful-subsets
2699-count-the-number-of-fair-pairs
2764-maximum-number-of-fish-in-a-grid
2766-find-the-prefix-common-array-of-two-arrays
2792-neighboring-bitwise-xor
2818-maximum-strictly-increasing-cells-in-a-matrix
2856-count-complete-subarrays-in-an-array
2888-minimum-index-of-a-valid-split
2915-count-of-interesting-subarrays
3001-apply-operations-to-maximize-score
3152-maximum-value-of-an-ordered-triplet-ii
3154-maximum-value-of-an-ordered-triplet-i
3171-minimum-equal-sum-of-two-arrays-after-replacing-zeros
3213-count-subarrays-where-max-element-appears-at-least-k-times
3219-make-lexicographically-smallest-array-by-swapping-elements
3227-find-missing-and-repeated-values
3309-count-prefix-and-suffix-pairs-i
3329-find-the-length-of-the-longest-common-prefix
3332-minimum-operations-to-exceed-threshold-value-ii
3348-minimum-cost-walk-in-weighted-graph
3355-minimum-levels-to-gain-more-points
3372-longest-strictly-increasing-or-strictly-decreasing-subarray
3382-find-the-number-of-subarrays-where-boundary-elements-are-maximum
3429-special-array-i
3430-count-days-without-meetings
3434-find-the-number-of-distinct-colors-among-the-balls
3438-peaks-in-array
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3483-alternating-groups-ii
3621-minimum-operations-to-make-array-values-equal-to-k
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii
3639-zero-array-transformation-i
3643-zero-array-transformation-ii
3648-find-the-maximum-number-of-fruits-collected
3656-minimum-number-of-operations-to-make-elements-in-array-distinct
3657-check-if-grid-can-be-cut-into-sections
3685-count-subarrays-of-length-three-with-a-condition
3733-length-of-longest-v-shaped-diagonal-segment
3790-fruits-into-baskets-ii

Prefix Sum

0560-subarray-sum-equals-k
0878-shifting-letters
1184-car-pooling
1477-product-of-the-last-k-numbers
1631-number-of-sub-arrays-with-odd-sum
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
2059-unique-length-3-palindromic-subsequences
2145-grid-game
2249-count-the-hidden-sequences
2358-number-of-ways-to-split-array
2394-count-subarrays-with-score-less-than-k
2465-shifting-letters-ii
2915-count-of-interesting-subarrays
3355-minimum-levels-to-gain-more-points
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3639-zero-array-transformation-i
3643-zero-array-transformation-ii

Rolling Hash

0187-repeated-dna-sequences
0214-shortest-palindrome
1122-longest-duplicate-substring
1244-distinct-echo-substrings
1508-longest-happy-prefix
2326-sum-of-scores-of-built-strings
3296-minimum-time-to-revert-word-to-initial-state-ii
3309-count-prefix-and-suffix-pairs-i

Hash Function

0187-repeated-dna-sequences
0214-shortest-palindrome
1122-longest-duplicate-substring
1244-distinct-echo-substrings
1508-longest-happy-prefix
2326-sum-of-scores-of-built-strings
3296-minimum-time-to-revert-word-to-initial-state-ii
3309-count-prefix-and-suffix-pairs-i

Binary Search

0153-find-minimum-in-rotated-sorted-array
0794-swim-in-rising-water
1122-longest-duplicate-substring
1294-range-frequency-queries
1335-maximum-candies-allocated-to-k-children
2180-maximum-number-of-tasks-you-can-assign
2280-count-good-triplets-in-an-array
2326-sum-of-scores-of-built-strings
2394-count-subarrays-with-score-less-than-k
2591-frog-jump-ii
2614-maximum-count-of-positive-integer-and-negative-integer
2665-minimum-time-to-repair-cars
2690-house-robber-iv
2699-count-the-number-of-fair-pairs
2818-maximum-strictly-increasing-cells-in-a-matrix
3382-find-the-number-of-subarrays-where-boundary-elements-are-maximum
3643-zero-array-transformation-ii
3790-fruits-into-baskets-ii

Sliding Window

0003-longest-substring-without-repeating-characters
0187-repeated-dna-sequences
0940-fruit-into-baskets
1122-longest-duplicate-substring
1460-number-of-substrings-containing-all-three-characters
2394-count-subarrays-with-score-less-than-k
2463-minimum-recolors-to-get-k-consecutive-black-blocks
2478-longest-nice-subarray
2527-count-subarrays-with-fixed-bounds
2626-count-the-number-of-good-subarrays
2856-count-complete-subarrays-in-an-array
3213-count-subarrays-where-max-element-appears-at-least-k-times
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3483-alternating-groups-ii
3569-count-of-substrings-containing-every-vowel-and-k-consonants-ii

Suffix Array

1122-longest-duplicate-substring
2326-sum-of-scores-of-built-strings

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0127-word-ladder
0187-repeated-dna-sequences
0208-implement-trie-prefix-tree
0421-maximum-xor-of-two-numbers-in-an-array
0560-subarray-sum-equals-k
0768-partition-labels
0797-rabbits-in-forest
0893-all-nodes-distance-k-in-binary-tree
0905-length-of-longest-fibonacci-subsequence
0925-construct-binary-tree-from-preorder-and-postorder-traversal
0940-fruit-into-baskets
0952-word-subsets
1160-letter-tile-possibilities
1218-lowest-common-ancestor-of-deepest-leaves
1227-number-of-equivalent-domino-pairs
1294-range-frequency-queries
1364-tuple-with-same-product
1387-find-elements-in-a-contaminated-binary-tree
1460-number-of-substrings-containing-all-three-characters
1500-count-largest-group
1502-construct-k-palindrome-strings
1915-check-if-one-string-swap-can-make-strings-equal
2059-unique-length-3-palindromic-subsequences
2107-find-unique-binary-string
2186-count-vowel-substrings-of-a-string
2215-finding-3-digit-even-numbers
2220-find-all-possible-recipes-from-given-supplies
2308-divide-array-into-equal-pairs
2362-minimum-rounds-to-complete-all-tasks
2434-design-a-number-container-system
2448-count-number-of-bad-pairs
2461-amount-of-time-for-binary-tree-to-be-infected
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2626-count-the-number-of-good-subarrays
2685-first-completely-painted-row-or-column
2696-the-number-of-beautiful-subsets
2766-find-the-prefix-common-array-of-two-arrays
2818-maximum-strictly-increasing-cells-in-a-matrix
2856-count-complete-subarrays-in-an-array
2888-minimum-index-of-a-valid-split
2915-count-of-interesting-subarrays
3227-find-missing-and-repeated-values
3329-find-the-length-of-the-longest-common-prefix
3434-find-the-number-of-distinct-colors-among-the-balls
3455-minimum-length-of-string-after-operations
3548-find-the-count-of-good-integers
3569-count-of-substrings-containing-every-vowel-and-k-consonants-ii
3621-minimum-operations-to-make-array-values-equal-to-k
3634-find-mirror-score-of-a-string
3656-minimum-number-of-operations-to-make-elements-in-array-distinct

Bit Manipulation

0187-repeated-dna-sequences
0421-maximum-xor-of-two-numbers-in-an-array
1993-sum-of-all-subset-xor-totals
2059-unique-length-3-palindromic-subsequences
2308-divide-array-into-equal-pairs
2478-longest-nice-subarray
2509-minimize-xor
2533-bitwise-xor-of-all-pairings
2766-find-the-prefix-common-array-of-two-arrays
2792-neighboring-bitwise-xor
3348-minimum-cost-walk-in-weighted-graph
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i

Trie

0014-longest-common-prefix
0208-implement-trie-prefix-tree
0421-maximum-xor-of-two-numbers-in-an-array
1244-distinct-echo-substrings
3309-count-prefix-and-suffix-pairs-i
3329-find-the-length-of-the-longest-common-prefix

Dynamic Programming

0005-longest-palindromic-substring
0064-minimum-path-sum
0070-climbing-stairs
0121-best-time-to-buy-and-sell-stock
0152-maximum-product-subarray
0233-number-of-digit-one
0329-longest-increasing-path-in-a-matrix
0368-largest-divisible-subset
0416-partition-equal-subset-sum
0647-palindromic-substrings
0741-cherry-pickup
0747-min-cost-climbing-stairs
0806-domino-and-tromino-tiling
0868-push-dominoes
0902-minimum-number-of-refueling-stops
0905-length-of-longest-fibonacci-subsequence
1013-fibonacci-number
1170-shortest-common-supersequence
1234-number-of-paths-with-max-score
1631-number-of-sub-arrays-with-odd-sum
1849-maximum-absolute-sum-of-any-subarray
2090-number-of-ways-to-arrive-at-destination
2262-solving-questions-with-brainpower
2409-number-of-increasing-paths-in-a-grid
2415-count-the-number-of-ideal-arrays
2477-number-of-ways-to-reach-a-position-after-exactly-k-steps
2562-count-ways-to-build-good-strings
2696-the-number-of-beautiful-subsets
2818-maximum-strictly-increasing-cells-in-a-matrix
3243-count-the-number-of-powerful-integers
3637-count-number-of-balanced-permutations
3648-find-the-maximum-number-of-fruits-collected
3733-length-of-longest-v-shaped-diagonal-segment

Stack

0094-binary-tree-inorder-traversal
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
2021-remove-all-occurrences-of-a-substring
2221-check-if-a-parentheses-string-can-be-valid
2456-construct-smallest-number-from-di-string
3001-apply-operations-to-maximize-score
3382-find-the-number-of-subarrays-where-boundary-elements-are-maximum
3447-clear-digits
3634-find-mirror-score-of-a-string

Simulation

1184-car-pooling
2021-remove-all-occurrences-of-a-substring
2048-build-array-from-permutation
3332-minimum-operations-to-exceed-threshold-value-ii
3434-find-the-number-of-distinct-colors-among-the-balls
3447-clear-digits
3634-find-mirror-score-of-a-string
3790-fruits-into-baskets-ii

Greedy

0768-partition-labels
0797-rabbits-in-forest
0902-minimum-number-of-refueling-stops
1049-minimum-domino-rotations-for-equal-row
1502-construct-k-palindrome-strings
2094-remove-stones-to-minimize-the-total
2180-maximum-number-of-tasks-you-can-assign
2221-check-if-a-parentheses-string-can-be-valid
2310-minimum-operations-to-halve-array-sum
2362-minimum-rounds-to-complete-all-tasks
2456-construct-smallest-number-from-di-string
2509-minimize-xor
2591-frog-jump-ii
2681-put-marbles-in-bags
3001-apply-operations-to-maximize-score
3171-minimum-equal-sum-of-two-arrays-after-replacing-zeros

Counting

1160-letter-tile-possibilities
1227-number-of-equivalent-domino-pairs
1364-tuple-with-same-product
1396-count-servers-that-communicate
1502-construct-k-palindrome-strings
1915-check-if-one-string-swap-can-make-strings-equal
2308-divide-array-into-equal-pairs
2362-minimum-rounds-to-complete-all-tasks
2448-count-number-of-bad-pairs
2614-maximum-count-of-positive-integer-and-negative-integer
3455-minimum-length-of-string-after-operations

Divide and Conquer

0215-kth-largest-element-in-an-array
0925-construct-binary-tree-from-preorder-and-postorder-traversal
2280-count-good-triplets-in-an-array

Sorting

0056-merge-intervals
0215-kth-largest-element-in-an-array
0368-largest-divisible-subset
1184-car-pooling
2160-minimum-operations-to-make-a-uni-value-grid
2180-maximum-number-of-tasks-you-can-assign
2215-finding-3-digit-even-numbers
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2588-maximum-number-of-points-from-grid-queries
2681-put-marbles-in-bags
2696-the-number-of-beautiful-subsets
2699-count-the-number-of-fair-pairs
2818-maximum-strictly-increasing-cells-in-a-matrix
2888-minimum-index-of-a-valid-split
3001-apply-operations-to-maximize-score
3219-make-lexicographically-smallest-array-by-swapping-elements
3430-count-days-without-meetings
3657-check-if-grid-can-be-cut-into-sections

Heap (Priority Queue)

0215-kth-largest-element-in-an-array
0407-trapping-rain-water-ii
0744-network-delay-time
0794-swim-in-rising-water
0902-minimum-number-of-refueling-stops
1184-car-pooling
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
2094-remove-stones-to-minimize-the-total
2310-minimum-operations-to-halve-array-sum
2434-design-a-number-container-system
2473-max-sum-of-a-pair-with-equal-sum-of-digits
2588-maximum-number-of-points-from-grid-queries
2681-put-marbles-in-bags
3332-minimum-operations-to-exceed-threshold-value-ii
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii

Quickselect

0215-kth-largest-element-in-an-array

Brainteaser

2533-bitwise-xor-of-all-pairings

Breadth-First Search

0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0107-binary-tree-level-order-traversal-ii
0111-minimum-depth-of-binary-tree
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0127-word-ladder
0199-binary-tree-right-side-view
0310-minimum-height-trees
0329-longest-increasing-path-in-a-matrix
0407-trapping-rain-water-ii
0547-number-of-provinces
0684-redundant-connection
0744-network-delay-time
0794-swim-in-rising-water
0813-all-paths-from-source-to-target
0820-find-eventual-safe-states
0854-making-a-large-island
0893-all-nodes-distance-k-in-binary-tree
1218-lowest-common-ancestor-of-deepest-leaves
1387-find-elements-in-a-contaminated-binary-tree
1396-count-servers-that-communicate
1414-shortest-path-in-a-grid-with-obstacles-elimination
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1558-course-schedule-iv
1876-map-of-highest-peak
2409-number-of-increasing-paths-in-a-grid
2461-amount-of-time-for-binary-tree-to-be-infected
2564-most-profitable-path-in-a-tree
2583-divide-nodes-into-the-maximum-number-of-groups
2588-maximum-number-of-points-from-grid-queries
2764-maximum-number-of-fish-in-a-grid
2793-count-the-number-of-complete-components

Graph

0310-minimum-height-trees
0329-longest-increasing-path-in-a-matrix
0547-number-of-provinces
0684-redundant-connection
0744-network-delay-time
0813-all-paths-from-source-to-target
0820-find-eventual-safe-states
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1558-course-schedule-iv
1661-minimum-number-of-vertices-to-reach-all-nodes
2090-number-of-ways-to-arrive-at-destination
2220-find-all-possible-recipes-from-given-supplies
2246-maximum-employees-to-be-invited-to-a-meeting
2409-number-of-increasing-paths-in-a-grid
2564-most-profitable-path-in-a-tree
2583-divide-nodes-into-the-maximum-number-of-groups
2793-count-the-number-of-complete-components
3348-minimum-cost-walk-in-weighted-graph
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii

Matrix

0064-minimum-path-sum
0329-longest-increasing-path-in-a-matrix
0407-trapping-rain-water-ii
0741-cherry-pickup
0794-swim-in-rising-water
0854-making-a-large-island
1234-number-of-paths-with-max-score
1396-count-servers-that-communicate
1414-shortest-path-in-a-grid-with-obstacles-elimination
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
1876-map-of-highest-peak
2145-grid-game
2160-minimum-operations-to-make-a-uni-value-grid
2409-number-of-increasing-paths-in-a-grid
2588-maximum-number-of-points-from-grid-queries
2685-first-completely-painted-row-or-column
2764-maximum-number-of-fish-in-a-grid
2818-maximum-strictly-increasing-cells-in-a-matrix
3227-find-missing-and-repeated-values
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii
3648-find-the-maximum-number-of-fruits-collected
3733-length-of-longest-v-shaped-diagonal-segment

Shortest Path

0744-network-delay-time
1485-minimum-cost-to-make-at-least-one-valid-path-in-a-grid
2090-number-of-ways-to-arrive-at-destination
3627-find-minimum-time-to-reach-last-room-i
3628-find-minimum-time-to-reach-last-room-ii

Depth-First Search

0094-binary-tree-inorder-traversal
0104-maximum-depth-of-binary-tree
0111-minimum-depth-of-binary-tree
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0129-sum-root-to-leaf-numbers
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0199-binary-tree-right-side-view
0310-minimum-height-trees
0329-longest-increasing-path-in-a-matrix
0547-number-of-provinces
0684-redundant-connection
0744-network-delay-time
0794-swim-in-rising-water
0813-all-paths-from-source-to-target
0820-find-eventual-safe-states
0854-making-a-large-island
0893-all-nodes-distance-k-in-binary-tree
1093-recover-a-tree-from-preorder-traversal
1218-lowest-common-ancestor-of-deepest-leaves
1387-find-elements-in-a-contaminated-binary-tree
1396-count-servers-that-communicate
1558-course-schedule-iv
2246-maximum-employees-to-be-invited-to-a-meeting
2409-number-of-increasing-paths-in-a-grid
2461-amount-of-time-for-binary-tree-to-be-infected
2564-most-profitable-path-in-a-tree
2764-maximum-number-of-fish-in-a-grid
2793-count-the-number-of-complete-components

Union Find

0547-number-of-provinces
0684-redundant-connection
0794-swim-in-rising-water
0854-making-a-large-island
1396-count-servers-that-communicate
2583-divide-nodes-into-the-maximum-number-of-groups
2588-maximum-number-of-points-from-grid-queries
2764-maximum-number-of-fish-in-a-grid
2793-count-the-number-of-complete-components
3219-make-lexicographically-smallest-array-by-swapping-elements
3348-minimum-cost-walk-in-weighted-graph

Topological Sort

0310-minimum-height-trees
0329-longest-increasing-path-in-a-matrix
0820-find-eventual-safe-states
1558-course-schedule-iv
2090-number-of-ways-to-arrive-at-destination
2220-find-all-possible-recipes-from-given-supplies
2246-maximum-employees-to-be-invited-to-a-meeting
2409-number-of-increasing-paths-in-a-grid

Tree

0094-binary-tree-inorder-traversal
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0107-binary-tree-level-order-traversal-ii
0111-minimum-depth-of-binary-tree
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0129-sum-root-to-leaf-numbers
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0199-binary-tree-right-side-view
0893-all-nodes-distance-k-in-binary-tree
0925-construct-binary-tree-from-preorder-and-postorder-traversal
1093-recover-a-tree-from-preorder-traversal
1218-lowest-common-ancestor-of-deepest-leaves
1387-find-elements-in-a-contaminated-binary-tree
2461-amount-of-time-for-binary-tree-to-be-infected
2564-most-profitable-path-in-a-tree

Binary Tree

0094-binary-tree-inorder-traversal
0102-binary-tree-level-order-traversal
0103-binary-tree-zigzag-level-order-traversal
0104-maximum-depth-of-binary-tree
0107-binary-tree-level-order-traversal-ii
0111-minimum-depth-of-binary-tree
0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0129-sum-root-to-leaf-numbers
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0199-binary-tree-right-side-view
0893-all-nodes-distance-k-in-binary-tree
0925-construct-binary-tree-from-preorder-and-postorder-traversal
1093-recover-a-tree-from-preorder-traversal
1218-lowest-common-ancestor-of-deepest-leaves
1387-find-elements-in-a-contaminated-binary-tree
2461-amount-of-time-for-binary-tree-to-be-infected

Linked List

0116-populating-next-right-pointers-in-each-node
0117-populating-next-right-pointers-in-each-node-ii
0206-reverse-linked-list

Recursion

0206-reverse-linked-list
0233-number-of-digit-one
0326-power-of-three
1013-fibonacci-number
2050-count-good-numbers

Math

0070-climbing-stairs
0233-number-of-digit-one
0326-power-of-three
0368-largest-divisible-subset
0797-rabbits-in-forest
1013-fibonacci-number
1421-find-numbers-with-even-number-of-digits
1477-product-of-the-last-k-numbers
1500-count-largest-group
1631-number-of-sub-arrays-with-odd-sum
1889-check-if-number-is-a-sum-of-powers-of-three
1993-sum-of-all-subset-xor-totals
2050-count-good-numbers
2160-minimum-operations-to-make-a-uni-value-grid
2415-count-the-number-of-ideal-arrays
2448-count-number-of-bad-pairs
2477-number-of-ways-to-reach-a-position-after-exactly-k-steps
2610-closest-prime-numbers-in-range
2649-count-total-number-of-colored-cells
2696-the-number-of-beautiful-subsets
2802-find-the-punishment-number-of-an-integer
2998-count-symmetric-integers
3001-apply-operations-to-maximize-score
3227-find-missing-and-repeated-values
3243-count-the-number-of-powerful-integers
3548-find-the-count-of-good-integers
3637-count-number-of-balanced-permutations

Memoization

0070-climbing-stairs
0329-longest-increasing-path-in-a-matrix
1013-fibonacci-number
2409-number-of-increasing-paths-in-a-grid
2818-maximum-strictly-increasing-cells-in-a-matrix
3733-length-of-longest-v-shaped-diagonal-segment

Combinatorics

1993-sum-of-all-subset-xor-totals
2415-count-the-number-of-ideal-arrays
2477-number-of-ways-to-reach-a-position-after-exactly-k-steps
2696-the-number-of-beautiful-subsets
3548-find-the-count-of-good-integers
3637-count-number-of-balanced-permutations

Design

0208-implement-trie-prefix-tree
0307-range-sum-query-mutable
1294-range-frequency-queries
1387-find-elements-in-a-contaminated-binary-tree
1477-product-of-the-last-k-numbers
2434-design-a-number-container-system

Ordered Set

2280-count-good-triplets-in-an-array
2434-design-a-number-container-system
2818-maximum-strictly-increasing-cells-in-a-matrix

Data Stream

1477-product-of-the-last-k-numbers

Backtracking

0813-all-paths-from-source-to-target
1160-letter-tile-possibilities
1516-the-k-th-lexicographical-string-of-all-happy-strings-of-length-n
1819-construct-the-lexicographically-largest-valid-sequence
1993-sum-of-all-subset-xor-totals
2107-find-unique-binary-string
2456-construct-smallest-number-from-di-string
2696-the-number-of-beautiful-subsets
2802-find-the-punishment-number-of-an-integer

Number Theory

2415-count-the-number-of-ideal-arrays
2610-closest-prime-numbers-in-range
3001-apply-operations-to-maximize-score

Queue

2180-maximum-number-of-tasks-you-can-assign
2527-count-subarrays-with-fixed-bounds
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i

Monotonic Stack

3001-apply-operations-to-maximize-score
3382-find-the-number-of-subarrays-where-boundary-elements-are-maximum

Enumeration

1656-count-good-triplets
1993-sum-of-all-subset-xor-totals
2215-finding-3-digit-even-numbers
2998-count-symmetric-integers
3548-find-the-count-of-good-integers

Binary Indexed Tree

0307-range-sum-query-mutable
2280-count-good-triplets-in-an-array
3438-peaks-in-array

Segment Tree

0307-range-sum-query-mutable
1294-range-frequency-queries
2280-count-good-triplets-in-an-array
3438-peaks-in-array
3790-fruits-into-baskets-ii

Merge Sort

2280-count-good-triplets-in-an-array

Monotonic Queue

2180-maximum-number-of-tasks-you-can-assign
2527-count-subarrays-with-fixed-bounds