DSA

A collection of LeetCode questions to ace the coding interview! - Created using LeetHub v2

LeetCode Topics

Depth-First Search

0104-maximum-depth-of-binary-tree
0116-populating-next-right-pointers-in-each-node
0124-binary-tree-maximum-path-sum
0207-course-schedule
0210-course-schedule-ii
0236-lowest-common-ancestor-of-a-binary-tree
0269-alien-dictionary
0270-closest-binary-search-tree-value
0272-closest-binary-search-tree-value-ii
0297-serialize-and-deserialize-binary-tree
0298-binary-tree-longest-consecutive-sequence
0310-minimum-height-trees
0314-binary-tree-vertical-order-traversal
0333-largest-bst-subtree
0339-nested-list-weight-sum
0366-find-leaves-of-binary-tree
0399-evaluate-division
0437-path-sum-iii
0499-the-maze-iii
0545-boundary-of-binary-tree
0547-number-of-provinces
0642-design-search-autocomplete-system
0694-number-of-distinct-islands
0765-serialize-and-deserialize-n-ary-tree
0801-is-graph-bipartite
0854-making-a-large-island
0871-keys-and-rooms
0893-all-nodes-distance-k-in-binary-tree
0904-leaf-similar-trees
1116-maximum-level-sum-of-a-binary-tree
1150-two-sum-bsts
1271-web-crawler
1474-longest-zigzag-path-in-a-binary-tree
1544-count-good-nodes-in-binary-tree
1576-reorder-routes-to-make-all-paths-lead-to-the-city-zero
1650-find-root-of-n-ary-tree
1665-diameter-of-n-ary-tree
2121-find-if-path-exists-in-graph

Breadth-First Search

0104-maximum-depth-of-binary-tree
0116-populating-next-right-pointers-in-each-node
0127-word-ladder
0207-course-schedule
0210-course-schedule-ii
0269-alien-dictionary
0286-walls-and-gates
0297-serialize-and-deserialize-binary-tree
0310-minimum-height-trees
0314-binary-tree-vertical-order-traversal
0317-shortest-distance-from-all-buildings
0339-nested-list-weight-sum
0399-evaluate-division
0499-the-maze-iii
0547-number-of-provinces
0694-number-of-distinct-islands
0765-serialize-and-deserialize-n-ary-tree
0801-is-graph-bipartite
0854-making-a-large-island
0871-keys-and-rooms
0893-all-nodes-distance-k-in-binary-tree
1036-rotting-oranges
1076-brace-expansion
1116-maximum-level-sum-of-a-binary-tree
1271-web-crawler
1544-count-good-nodes-in-binary-tree
1576-reorder-routes-to-make-all-paths-lead-to-the-city-zero
2038-nearest-exit-from-entrance-in-maze
2121-find-if-path-exists-in-graph
2583-divide-nodes-into-the-maximum-number-of-groups

Array

0001-two-sum
0011-container-with-most-water
0018-4sum
0031-next-permutation
0034-find-first-and-last-position-of-element-in-sorted-array
0041-first-missing-positive
0073-set-matrix-zeroes
0079-word-search
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0136-single-number
0139-word-break
0162-find-peak-element
0198-house-robber
0215-kth-largest-element-in-an-array
0216-combination-sum-iii
0217-contains-duplicate
0238-product-of-array-except-self
0239-sliding-window-maximum
0247-strobogrammatic-number-ii
0255-verify-preorder-sequence-in-binary-search-tree
0256-paint-house
0269-alien-dictionary
0271-encode-and-decode-strings
0280-wiggle-sort
0281-zigzag-iterator
0283-move-zeroes
0286-walls-and-gates
0305-number-of-islands-ii
0311-sparse-matrix-multiplication
0317-shortest-distance-from-all-buildings
0334-increasing-triplet-subsequence
0346-moving-average-from-data-stream
0347-top-k-frequent-elements
0348-design-tic-tac-toe
0353-design-snake-game
0362-design-hit-counter
0377-combination-sum-iv
0380-insert-delete-getrandom-o1
0399-evaluate-division
0435-non-overlapping-intervals
0452-minimum-number-of-arrows-to-burst-balloons
0484-find-permutation
0487-max-consecutive-ones-ii
0494-target-sum
0499-the-maze-iii
0523-continuous-subarray-sum
0560-subarray-sum-equals-k
0604-design-compressed-string-iterator
0605-can-place-flowers
0616-add-bold-tag-in-string
0643-maximum-average-subarray-i
0644-maximum-average-subarray-ii
0714-best-time-to-buy-and-sell-stock-with-transaction-fee
0723-candy-crush
0724-find-pivot-index
0735-asteroid-collision
0739-daily-temperatures
0745-find-smallest-letter-greater-than-target
0747-min-cost-climbing-stairs
0762-find-anagram-mappings
0816-design-hashset
0817-design-hashmap
0854-making-a-large-island
0879-maximize-distance-to-closest-person
0907-koko-eating-bananas
0932-monotonic-array
1014-k-closest-points-to-origin
1036-rotting-oranges
1046-max-consecutive-ones-iii
1049-minimum-domino-rotations-for-equal-row
1052-campus-bikes
1056-capacity-to-ship-packages-within-d-days
1059-missing-element-in-sorted-array
1074-high-five
1085-the-earliest-moment-when-everyone-become-friends
1102-check-if-a-number-is-majority-element-in-a-sorted-array
1108-analyze-user-website-visit-pattern
1126-minimum-cost-to-connect-sticks
1143-find-smallest-common-element-in-all-rows
1164-missing-number-in-arithmetic-progression
1192-divide-chocolate
1200-remove-interval
1306-minimum-absolute-difference
1319-unique-number-of-occurrences
1345-perform-string-shifts
1364-tuple-with-same-product
1366-first-unique-number
1392-find-the-difference-of-two-arrays
1397-search-suggestions-system
1400-find-winner-on-a-tic-tac-toe-game
1477-product-of-the-last-k-numbers
1528-kids-with-the-greatest-number-of-candies
1586-longest-subarray-of-1s-after-deleting-one-element
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1672-find-the-index-of-the-large-integer
1744-number-of-ways-to-form-a-target-string-given-a-dictionary
1798-max-number-of-k-sum-pairs
1833-find-the-highest-altitude
1878-check-if-array-is-sorted-and-rotated
2038-nearest-exit-from-entrance-in-maze
2145-grid-game
2170-count-number-of-maximum-bitwise-or-subsets
2204-find-subsequence-of-length-k-with-the-largest-sum
2316-count-hills-and-valleys-in-an-array
2320-find-all-k-distant-indices-in-an-array
2387-partition-array-such-that-maximum-difference-is-k
2392-successful-pairs-of-spells-and-potions
2428-equal-row-and-column-pairs
2448-count-number-of-bad-pairs
2529-range-product-queries-of-powers
2552-maximum-sum-of-distinct-subarrays-with-length-k
2553-total-cost-to-hire-k-workers
2581-divide-players-into-teams-of-equal-skill
2614-maximum-count-of-positive-integer-and-negative-integer
2636-maximum-subsequence-score
2685-first-completely-painted-row-or-column
2718-minimum-operations-to-make-all-array-elements-equal
2808-painting-the-walls
3081-minimum-array-length-after-pair-removals
3329-find-the-length-of-the-longest-common-prefix
3332-minimum-operations-to-exceed-threshold-value-ii
3362-find-the-median-of-the-uniqueness-array
3372-longest-strictly-increasing-or-strictly-decreasing-subarray
3429-special-array-i
3434-find-the-number-of-distinct-colors-among-the-balls
3456-find-the-maximum-length-of-a-good-subsequence-i
3647-zero-array-transformation-iii
3751-maximum-frequency-after-subarray-operation
3788-maximum-unique-subarray-sum-after-deletion
3791-fruits-into-baskets-iii
3949-minimum-number-of-primes-to-sum-to-target

Dynamic Programming

0062-unique-paths
0072-edit-distance
0091-decode-ways
0124-binary-tree-maximum-path-sum
0139-word-break
0198-house-robber
0256-paint-house
0276-paint-fence
0333-largest-bst-subtree
0338-counting-bits
0377-combination-sum-iv
0392-is-subsequence
0435-non-overlapping-intervals
0487-max-consecutive-ones-ii
0494-target-sum
0647-palindromic-substrings
0651-4-keys-keyboard
0714-best-time-to-buy-and-sell-stock-with-transaction-fee
0747-min-cost-climbing-stairs
0804-rotated-digits
0806-domino-and-tromino-tiling
1236-n-th-tribonacci-number
1250-longest-common-subsequence
1474-longest-zigzag-path-in-a-binary-tree
1586-longest-subarray-of-1s-after-deleting-one-element
1744-number-of-ways-to-form-a-target-string-given-a-dictionary
2395-longest-binary-subsequence-less-than-or-equal-to-k
2808-painting-the-walls
3024-string-transformation
3456-find-the-maximum-length-of-a-good-subsequence-i
3751-maximum-frequency-after-subarray-operation
3949-minimum-number-of-primes-to-sum-to-target

Backtracking

0017-letter-combinations-of-a-phone-number
0079-word-search
0216-combination-sum-iii
0254-factor-combinations
0282-expression-add-operators
0494-target-sum
1076-brace-expansion
2140-longest-subsequence-repeated-k-times
2170-count-number-of-maximum-bitwise-or-subsets

Hash Table

0001-two-sum
0013-roman-to-integer
0017-letter-combinations-of-a-phone-number
0041-first-missing-positive
0073-set-matrix-zeroes
0076-minimum-window-substring
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0127-word-ladder
0139-word-break
0142-linked-list-cycle-ii
0146-lru-cache
0159-longest-substring-with-at-most-two-distinct-characters
0160-intersection-of-two-linked-lists
0166-fraction-to-recurring-decimal
0208-implement-trie-prefix-tree
0217-contains-duplicate
0242-valid-anagram
0246-strobogrammatic-number
0266-palindrome-permutation
0305-number-of-islands-ii
0311-sparse-matrix-multiplication
0314-binary-tree-vertical-order-traversal
0340-longest-substring-with-at-most-k-distinct-characters
0347-top-k-frequent-elements
0348-design-tic-tac-toe
0353-design-snake-game
0355-design-twitter
0358-rearrange-string-k-distance-apart
0380-insert-delete-getrandom-o1
0438-find-all-anagrams-in-a-string
0523-continuous-subarray-sum
0535-encode-and-decode-tinyurl
0560-subarray-sum-equals-k
0567-permutation-in-string
0588-design-in-memory-file-system
0616-add-bold-tag-in-string
0694-number-of-distinct-islands
0762-find-anagram-mappings
0816-design-hashset
0817-design-hashmap
0893-all-nodes-distance-k-in-binary-tree
1074-high-five
1084-find-k-length-substrings-with-no-repeated-characters
1108-analyze-user-website-visit-pattern
1143-find-smallest-common-element-in-all-rows
1176-design-a-leaderboard
1270-dinner-plate-stacks
1319-unique-number-of-occurrences
1364-tuple-with-same-product
1366-first-unique-number
1392-find-the-difference-of-two-arrays
1400-find-winner-on-a-tic-tac-toe-game
1650-find-root-of-n-ary-tree
1777-determine-if-two-strings-are-close
1790-lowest-common-ancestor-of-a-binary-tree-iii
1798-max-number-of-k-sum-pairs
1915-check-if-one-string-swap-can-make-strings-equal
1982-remove-duplicates-from-an-unsorted-linked-list
2186-count-vowel-substrings-of-a-string
2204-find-subsequence-of-length-k-with-the-largest-sum
2413-smallest-number-in-infinite-set
2428-equal-row-and-column-pairs
2434-design-a-number-container-system
2448-count-number-of-bad-pairs
2552-maximum-sum-of-distinct-subarrays-with-length-k
2581-divide-players-into-teams-of-equal-skill
2685-first-completely-painted-row-or-column
3081-minimum-array-length-after-pair-removals
3329-find-the-length-of-the-longest-common-prefix
3362-find-the-median-of-the-uniqueness-array
3434-find-the-number-of-distinct-colors-among-the-balls
3456-find-the-maximum-length-of-a-good-subsequence-i
3751-maximum-frequency-after-subarray-operation
3788-maximum-unique-subarray-sum-after-deletion

Prefix Sum

0238-product-of-array-except-self
0523-continuous-subarray-sum
0560-subarray-sum-equals-k
0644-maximum-average-subarray-ii
0724-find-pivot-index
1046-max-consecutive-ones-iii
1477-product-of-the-last-k-numbers
1833-find-the-highest-altitude
2145-grid-game
2529-range-product-queries-of-powers
2718-minimum-operations-to-make-all-array-elements-equal
3647-zero-array-transformation-iii
3751-maximum-frequency-after-subarray-operation

String

0006-zigzag-conversion
0008-string-to-integer-atoi
0013-roman-to-integer
0014-longest-common-prefix
0017-letter-combinations-of-a-phone-number
0072-edit-distance
0076-minimum-window-substring
0079-word-search
0091-decode-ways
0127-word-ladder
0139-word-break
0151-reverse-words-in-a-string
0159-longest-substring-with-at-most-two-distinct-characters
0161-one-edit-distance
0166-fraction-to-recurring-decimal
0186-reverse-words-in-a-string-ii
0208-implement-trie-prefix-tree
0227-basic-calculator-ii
0242-valid-anagram
0246-strobogrammatic-number
0247-strobogrammatic-number-ii
0266-palindrome-permutation
0269-alien-dictionary
0271-encode-and-decode-strings
0282-expression-add-operators
0297-serialize-and-deserialize-binary-tree
0340-longest-substring-with-at-most-k-distinct-characters
0345-reverse-vowels-of-a-string
0358-rearrange-string-k-distance-apart
0392-is-subsequence
0394-decode-string
0399-evaluate-division
0402-remove-k-digits
0438-find-all-anagrams-in-a-string
0443-string-compression
0484-find-permutation
0499-the-maze-iii
0535-encode-and-decode-tinyurl
0567-permutation-in-string
0588-design-in-memory-file-system
0604-design-compressed-string-iterator
0616-add-bold-tag-in-string
0642-design-search-autocomplete-system
0647-palindromic-substrings
0649-dota2-senate
0657-robot-return-to-origin
0680-valid-palindrome-ii
0765-serialize-and-deserialize-n-ary-tree
0785-basic-calculator-iii
1051-shortest-way-to-form-string
1076-brace-expansion
1084-find-k-length-substrings-with-no-repeated-characters
1108-analyze-user-website-visit-pattern
1119-robot-bounded-in-circle
1131-count-substrings-with-only-one-distinct-letter
1146-greatest-common-divisor-of-strings
1250-longest-common-subsequence
1271-web-crawler
1345-perform-string-shifts
1397-search-suggestions-system
1567-maximum-number-of-vowels-in-a-substring-of-given-length
1744-number-of-ways-to-form-a-target-string-given-a-dictionary
1777-determine-if-two-strings-are-close
1894-merge-strings-alternately
1915-check-if-one-string-swap-can-make-strings-equal
2140-longest-subsequence-repeated-k-times
2186-count-vowel-substrings-of-a-string
2260-divide-a-string-into-groups-of-size-k
2395-longest-binary-subsequence-less-than-or-equal-to-k
2470-removing-stars-from-a-string
2800-minimum-string-length-after-removing-substrings
3024-string-transformation
3329-find-the-length-of-the-longest-common-prefix
3447-clear-digits
3617-find-the-original-typed-string-i
3931-process-string-with-special-operations-i

Matrix

0073-set-matrix-zeroes
0079-word-search
0286-walls-and-gates
0311-sparse-matrix-multiplication
0317-shortest-distance-from-all-buildings
0348-design-tic-tac-toe
0499-the-maze-iii
0723-candy-crush
0854-making-a-large-island
1036-rotting-oranges
1143-find-smallest-common-element-in-all-rows
1400-find-winner-on-a-tic-tac-toe-game
2038-nearest-exit-from-entrance-in-maze
2145-grid-game
2428-equal-row-and-column-pairs
2685-first-completely-painted-row-or-column

Math

0002-add-two-numbers
0013-roman-to-integer
0062-unique-paths
0166-fraction-to-recurring-decimal
0227-basic-calculator-ii
0282-expression-add-operators
0369-plus-one-linked-list
0380-insert-delete-getrandom-o1
0445-add-two-numbers-ii
0492-construct-the-rectangle
0523-continuous-subarray-sum
0651-4-keys-keyboard
0785-basic-calculator-iii
0804-rotated-digits
1014-k-closest-points-to-origin
1069-confusing-number
1090-armstrong-number
1119-robot-bounded-in-circle
1131-count-substrings-with-only-one-distinct-letter
1146-greatest-common-divisor-of-strings
1164-missing-number-in-arithmetic-progression
1236-n-th-tribonacci-number
1345-perform-string-shifts
1477-product-of-the-last-k-numbers
2448-count-number-of-bad-pairs
3024-string-transformation
3600-find-the-k-th-character-in-string-game-i
3949-minimum-number-of-primes-to-sum-to-target

Simulation

0348-design-tic-tac-toe
0353-design-snake-game
0657-robot-return-to-origin
0723-candy-crush
0735-asteroid-collision
1119-robot-bounded-in-circle
1400-find-winner-on-a-tic-tac-toe-game
2260-divide-a-string-into-groups-of-size-k
2428-equal-row-and-column-pairs
2470-removing-stars-from-a-string
2553-total-cost-to-hire-k-workers
2800-minimum-string-length-after-removing-substrings
3332-minimum-operations-to-exceed-threshold-value-ii
3434-find-the-number-of-distinct-colors-among-the-balls
3447-clear-digits
3600-find-the-k-th-character-in-string-game-i
3931-process-string-with-special-operations-i

Two Pointers

0011-container-with-most-water
0018-4sum
0019-remove-nth-node-from-end-of-list
0031-next-permutation
0086-partition-list
0142-linked-list-cycle-ii
0151-reverse-words-in-a-string
0160-intersection-of-two-linked-lists
0161-one-edit-distance
0186-reverse-words-in-a-string-ii
0234-palindrome-linked-list
0246-strobogrammatic-number
0272-closest-binary-search-tree-value-ii
0277-find-the-celebrity
0283-move-zeroes
0345-reverse-vowels-of-a-string
0392-is-subsequence
0443-string-compression
0567-permutation-in-string
0647-palindromic-substrings
0680-valid-palindrome-ii
0723-candy-crush
1051-shortest-way-to-form-string
1150-two-sum-bsts
1404-print-immutable-linked-list-in-reverse
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1790-lowest-common-ancestor-of-a-binary-tree-iii
1798-max-number-of-k-sum-pairs
1894-merge-strings-alternately
2216-delete-the-middle-node-of-a-linked-list
2236-maximum-twin-sum-of-a-linked-list
2320-find-all-k-distant-indices-in-an-array
2392-successful-pairs-of-spells-and-potions
2553-total-cost-to-hire-k-workers
2581-divide-players-into-teams-of-equal-skill
3081-minimum-array-length-after-pair-removals

Sorting

0018-4sum
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0242-valid-anagram
0280-wiggle-sort
0314-binary-tree-vertical-order-traversal
0347-top-k-frequent-elements
0358-rearrange-string-k-distance-apart
0435-non-overlapping-intervals
0452-minimum-number-of-arrows-to-burst-balloons
0588-design-in-memory-file-system
0642-design-search-autocomplete-system
1014-k-closest-points-to-origin
1052-campus-bikes
1074-high-five
1085-the-earliest-moment-when-everyone-become-friends
1108-analyze-user-website-visit-pattern
1176-design-a-leaderboard
1306-minimum-absolute-difference
1397-search-suggestions-system
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1777-determine-if-two-strings-are-close
1798-max-number-of-k-sum-pairs
2204-find-subsequence-of-length-k-with-the-largest-sum
2387-partition-array-such-that-maximum-difference-is-k
2392-successful-pairs-of-spells-and-potions
2581-divide-players-into-teams-of-equal-skill
2636-maximum-subsequence-score
2718-minimum-operations-to-make-all-array-elements-equal
3647-zero-array-transformation-iii

Heap (Priority Queue)

0215-kth-largest-element-in-an-array
0239-sliding-window-maximum
0272-closest-binary-search-tree-value-ii
0347-top-k-frequent-elements
0355-design-twitter
0358-rearrange-string-k-distance-apart
0499-the-maze-iii
0642-design-search-autocomplete-system
1014-k-closest-points-to-origin
1052-campus-bikes
1074-high-five
1126-minimum-cost-to-connect-sticks
1270-dinner-plate-stacks
1397-search-suggestions-system
2204-find-subsequence-of-length-k-with-the-largest-sum
2413-smallest-number-in-infinite-set
2434-design-a-number-container-system
2553-total-cost-to-hire-k-workers
2636-maximum-subsequence-score
3332-minimum-operations-to-exceed-threshold-value-ii
3647-zero-array-transformation-iii

Database

0175-combine-two-tables
0176-second-highest-salary
0180-consecutive-numbers
0182-duplicate-emails
0183-customers-who-never-order
0184-department-highest-salary
0185-department-top-three-salaries
0196-delete-duplicate-emails
0262-trips-and-users
0579-find-cumulative-salary-of-an-employee
0584-find-customer-referee
0585-investments-in-2016
0586-customer-placing-the-largest-number-of-orders
0595-big-countries
0596-classes-more-than-5-students
0601-human-traffic-of-stadium
0602-friend-requests-ii-who-has-the-most-friends
0603-consecutive-available-seats
0607-sales-person
0608-tree-node
0610-triangle-judgement
0613-shortest-distance-in-a-line
0619-biggest-single-number
0626-exchange-seats
0627-swap-salary
1135-customers-who-bought-all-products
1136-actors-and-directors-who-cooperated-at-least-three-times
1154-product-sales-analysis-ii
1155-product-sales-analysis-iii
1161-project-employees-i
1163-project-employees-iii
1172-sales-analysis-i
1173-sales-analysis-ii
1174-sales-analysis-iii
1179-game-play-analysis-i
1180-game-play-analysis-ii
1181-game-play-analysis-iii
1182-game-play-analysis-iv
1214-highest-grade-for-each-student
1245-user-activity-for-the-past-30-days-i
1258-article-views-i
1268-market-analysis-i
1278-product-price-at-a-given-date
1291-immediate-food-delivery-i
1292-immediate-food-delivery-ii
1301-reformat-department-table
1317-monthly-transactions-i
1327-last-person-to-fit-in-the-bus
1338-queries-quality-and-percentage
1339-team-scores-in-football-tournament
1357-report-contiguous-dates
1390-average-selling-price
1399-page-recommendations
1405-all-people-report-to-the-given-manager
1420-find-the-start-and-end-number-of-continuous-ranges
1438-find-the-team-size
1452-restaurant-growth
1462-list-the-products-ordered-in-a-period
1467-number-of-transactions-per-visit
1480-movie-rating
1481-students-with-invalid-departments
1509-replace-employee-id-with-the-unique-identifier
1536-customers-who-bought-products-a-and-b-but-not-c
1541-top-travellers
1546-find-the-quiet-students-in-all-exams
1551-npv-queries
1565-evaluate-boolean-expression
1578-apples-oranges
1579-active-users
1623-sales-by-day-of-the-week
1625-group-sold-products-by-the-date
1639-friendly-movies-streamed-last-month
1641-countries-you-can-safely-invest-in
1654-customer-order-frequency
1664-find-users-with-valid-e-mails
1670-patients-with-a-condition
1671-the-most-recent-three-orders
1688-the-most-recent-orders-for-each-product
1718-warehouse-manager
1734-bank-account-summary-ii
1735-the-most-frequently-ordered-products-for-each-customer
1749-sellers-with-no-sales
1759-find-the-missing-ids
1763-all-valid-triplets-that-can-represent-a-country
1773-percentage-of-users-attended-a-contest
1811-fix-names-in-a-table
1827-invalid-tweets
1837-daily-leads-and-partners
1842-number-of-calls-between-two-persons
1852-biggest-window-between-visits
1877-find-followers-count
1882-the-number-of-employees-which-report-to-each-employee
1892-find-total-time-spent-by-each-employee
1898-leetflex-banned-accounts
1908-recyclable-and-low-fat-products
1914-find-the-subtasks-that-did-not-execute
1926-products-price-for-each-store
1932-grand-slam-titles
1942-primary-department-for-each-employee
1948-rearrange-products-table
1958-ad-free-sessions
1964-find-interview-candidates
1974-find-customers-with-positive-revenue-this-year
1981-maximum-transaction-each-day
2024-calculate-special-bonus
2041-the-latest-login-in-2020
2057-count-salary-categories
2110-employees-with-missing-information
2120-first-and-last-call-on-the-same-day
2127-employees-whose-manager-left-the-company
2302-order-two-columns-independently
2313-longest-winning-streak
2370-users-with-two-purchases-within-seven-days
2376-number-of-times-a-driver-was-a-passenger
2431-products-with-three-or-more-orders-in-two-consecutive-years
2451-product-sales-analysis-iv
2452-product-sales-analysis-v
2495-number-of-unique-subjects-taught-by-each-teacher
2534-employees-with-deductions
2613-customers-with-strictly-increasing-purchases
2853-consecutive-transactions-with-increasing-amounts
3255-pizza-toppings-cost-analysis
3520-year-on-year-growth-rate
3539-customer-purchasing-behavior-analysis

Trie

0014-longest-common-prefix
0139-word-break
0208-implement-trie-prefix-tree
0588-design-in-memory-file-system
0616-add-bold-tag-in-string
0642-design-search-autocomplete-system
1397-search-suggestions-system
3329-find-the-length-of-the-longest-common-prefix

Binary Search

0034-find-first-and-last-position-of-element-in-sorted-array
0162-find-peak-element
0270-closest-binary-search-tree-value
0362-design-hit-counter
0374-guess-number-higher-or-lower
0644-maximum-average-subarray-ii
0745-find-smallest-letter-greater-than-target
0907-koko-eating-bananas
1046-max-consecutive-ones-iii
1051-shortest-way-to-form-string
1056-capacity-to-ship-packages-within-d-days
1059-missing-element-in-sorted-array
1102-check-if-a-number-is-majority-element-in-a-sorted-array
1143-find-smallest-common-element-in-all-rows
1150-two-sum-bsts
1192-divide-chocolate
1397-search-suggestions-system
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1672-find-the-index-of-the-large-integer
2392-successful-pairs-of-spells-and-potions
2614-maximum-count-of-positive-integer-and-negative-integer
2718-minimum-operations-to-make-all-array-elements-equal
3081-minimum-array-length-after-pair-removals
3362-find-the-median-of-the-uniqueness-array
3791-fruits-into-baskets-iii

Sliding Window

0076-minimum-window-substring
0159-longest-substring-with-at-most-two-distinct-characters
0239-sliding-window-maximum
0340-longest-substring-with-at-most-k-distinct-characters
0438-find-all-anagrams-in-a-string
0487-max-consecutive-ones-ii
0567-permutation-in-string
0643-maximum-average-subarray-i
1046-max-consecutive-ones-iii
1084-find-k-length-substrings-with-no-repeated-characters
1567-maximum-number-of-vowels-in-a-substring-of-given-length
1586-longest-subarray-of-1s-after-deleting-one-element
2552-maximum-sum-of-distinct-subarrays-with-length-k
3362-find-the-median-of-the-uniqueness-array

Tree

0104-maximum-depth-of-binary-tree
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0116-populating-next-right-pointers-in-each-node
0124-binary-tree-maximum-path-sum
0236-lowest-common-ancestor-of-a-binary-tree
0255-verify-preorder-sequence-in-binary-search-tree
0270-closest-binary-search-tree-value
0272-closest-binary-search-tree-value-ii
0297-serialize-and-deserialize-binary-tree
0298-binary-tree-longest-consecutive-sequence
0314-binary-tree-vertical-order-traversal
0333-largest-bst-subtree
0366-find-leaves-of-binary-tree
0437-path-sum-iii
0450-delete-node-in-a-bst
0545-boundary-of-binary-tree
0765-serialize-and-deserialize-n-ary-tree
0783-search-in-a-binary-search-tree
0893-all-nodes-distance-k-in-binary-tree
0904-leaf-similar-trees
1116-maximum-level-sum-of-a-binary-tree
1150-two-sum-bsts
1474-longest-zigzag-path-in-a-binary-tree
1544-count-good-nodes-in-binary-tree
1650-find-root-of-n-ary-tree
1665-diameter-of-n-ary-tree
1790-lowest-common-ancestor-of-a-binary-tree-iii

Design

0146-lru-cache
0155-min-stack
0208-implement-trie-prefix-tree
0271-encode-and-decode-strings
0281-zigzag-iterator
0297-serialize-and-deserialize-binary-tree
0346-moving-average-from-data-stream
0348-design-tic-tac-toe
0353-design-snake-game
0355-design-twitter
0362-design-hit-counter
0380-insert-delete-getrandom-o1
0535-encode-and-decode-tinyurl
0588-design-in-memory-file-system
0604-design-compressed-string-iterator
0642-design-search-autocomplete-system
0716-max-stack
0816-design-hashset
0817-design-hashmap
0937-online-stock-span
0969-number-of-recent-calls
1176-design-a-leaderboard
1270-dinner-plate-stacks
1366-first-unique-number
1477-product-of-the-last-k-numbers
2413-smallest-number-in-infinite-set
2434-design-a-number-container-system

Binary Tree

0104-maximum-depth-of-binary-tree
0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0116-populating-next-right-pointers-in-each-node
0124-binary-tree-maximum-path-sum
0236-lowest-common-ancestor-of-a-binary-tree
0255-verify-preorder-sequence-in-binary-search-tree
0270-closest-binary-search-tree-value
0272-closest-binary-search-tree-value-ii
0297-serialize-and-deserialize-binary-tree
0298-binary-tree-longest-consecutive-sequence
0314-binary-tree-vertical-order-traversal
0333-largest-bst-subtree
0366-find-leaves-of-binary-tree
0437-path-sum-iii
0450-delete-node-in-a-bst
0545-boundary-of-binary-tree
0783-search-in-a-binary-search-tree
0893-all-nodes-distance-k-in-binary-tree
0904-leaf-similar-trees
1116-maximum-level-sum-of-a-binary-tree
1150-two-sum-bsts
1474-longest-zigzag-path-in-a-binary-tree
1544-count-good-nodes-in-binary-tree
1790-lowest-common-ancestor-of-a-binary-tree-iii

Memoization

0139-word-break
1236-n-th-tribonacci-number
2395-longest-binary-subsequence-less-than-or-equal-to-k

Stack

0155-min-stack
0227-basic-calculator-ii
0234-palindrome-linked-list
0255-verify-preorder-sequence-in-binary-search-tree
0272-closest-binary-search-tree-value-ii
0394-decode-string
0402-remove-k-digits
0445-add-two-numbers-ii
0484-find-permutation
0716-max-stack
0735-asteroid-collision
0739-daily-temperatures
0785-basic-calculator-iii
0937-online-stock-span
1150-two-sum-bsts
1270-dinner-plate-stacks
1404-print-immutable-linked-list-in-reverse
2236-maximum-twin-sum-of-a-linked-list
2470-removing-stars-from-a-string
2800-minimum-string-length-after-removing-substrings
3447-clear-digits

Bit Manipulation

0136-single-number
0266-palindrome-permutation
0338-counting-bits
1441-minimum-flips-to-make-a-or-b-equal-to-c
1650-find-root-of-n-ary-tree
2170-count-number-of-maximum-bitwise-or-subsets
2529-range-product-queries-of-powers
3600-find-the-k-th-character-in-string-game-i

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0086-partition-list
0116-populating-next-right-pointers-in-each-node
0142-linked-list-cycle-ii
0146-lru-cache
0160-intersection-of-two-linked-lists
0206-reverse-linked-list
0234-palindrome-linked-list
0237-delete-node-in-a-linked-list
0328-odd-even-linked-list
0355-design-twitter
0369-plus-one-linked-list
0445-add-two-numbers-ii
0716-max-stack
0816-design-hashset
0817-design-hashmap
0850-insert-into-a-sorted-circular-linked-list
1404-print-immutable-linked-list-in-reverse
1618-delete-n-nodes-after-m-nodes-of-a-linked-list
1982-remove-duplicates-from-an-unsorted-linked-list
2216-delete-the-middle-node-of-a-linked-list
2236-maximum-twin-sum-of-a-linked-list

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0206-reverse-linked-list
0234-palindrome-linked-list
0247-strobogrammatic-number-ii
0255-verify-preorder-sequence-in-binary-search-tree
0394-decode-string
0785-basic-calculator-iii
1404-print-immutable-linked-list-in-reverse
3600-find-the-k-th-character-in-string-game-i

Union Find

0305-number-of-islands-ii
0399-evaluate-division
0547-number-of-provinces
0694-number-of-distinct-islands
0801-is-graph-bipartite
0854-making-a-large-island
1085-the-earliest-moment-when-everyone-become-friends
2121-find-if-path-exists-in-graph
2583-divide-nodes-into-the-maximum-number-of-groups

Graph

0207-course-schedule
0210-course-schedule-ii
0269-alien-dictionary
0277-find-the-celebrity
0310-minimum-height-trees
0399-evaluate-division
0499-the-maze-iii
0511-all-paths-from-source-lead-to-destination
0547-number-of-provinces
0801-is-graph-bipartite
0871-keys-and-rooms
1101-parallel-courses
1576-reorder-routes-to-make-all-paths-lead-to-the-city-zero
2121-find-if-path-exists-in-graph
2583-divide-nodes-into-the-maximum-number-of-groups

Hash Function

0535-encode-and-decode-tinyurl
0694-number-of-distinct-islands
0816-design-hashset
0817-design-hashmap

String Matching

0616-add-bold-tag-in-string
3024-string-transformation

Queue

0239-sliding-window-maximum
0281-zigzag-iterator
0346-moving-average-from-data-stream
0353-design-snake-game
0362-design-hit-counter
0649-dota2-senate
0969-number-of-recent-calls
1366-first-unique-number

Data Stream

0346-moving-average-from-data-stream
0362-design-hit-counter
0642-design-search-autocomplete-system
0937-online-stock-span
0969-number-of-recent-calls
1366-first-unique-number
1477-product-of-the-last-k-numbers

Greedy

0011-container-with-most-water
0280-wiggle-sort
0334-increasing-triplet-subsequence
0358-rearrange-string-k-distance-apart
0402-remove-k-digits
0435-non-overlapping-intervals
0452-minimum-number-of-arrows-to-burst-balloons
0484-find-permutation
0605-can-place-flowers
0649-dota2-senate
0680-valid-palindrome-ii
0714-best-time-to-buy-and-sell-stock-with-transaction-fee
1049-minimum-domino-rotations-for-equal-row
1051-shortest-way-to-form-string
1126-minimum-cost-to-connect-sticks
2140-longest-subsequence-repeated-k-times
2387-partition-array-such-that-maximum-difference-is-k
2395-longest-binary-subsequence-less-than-or-equal-to-k
2636-maximum-subsequence-score
3081-minimum-array-length-after-pair-removals
3647-zero-array-transformation-iii
3751-maximum-frequency-after-subarray-operation
3788-maximum-unique-subarray-sum-after-deletion

Counting

0347-top-k-frequent-elements
0358-rearrange-string-k-distance-apart
1143-find-smallest-common-element-in-all-rows
1364-tuple-with-same-product
1777-determine-if-two-strings-are-close
1915-check-if-one-string-swap-can-make-strings-equal
2140-longest-subsequence-repeated-k-times
2448-count-number-of-bad-pairs
2614-maximum-count-of-positive-integer-and-negative-integer
3081-minimum-array-length-after-pair-removals

Topological Sort

0207-course-schedule
0210-course-schedule-ii
0269-alien-dictionary
0310-minimum-height-trees
0511-all-paths-from-source-lead-to-destination
1101-parallel-courses

Monotonic Stack

0255-verify-preorder-sequence-in-binary-search-tree
0402-remove-k-digits
0739-daily-temperatures
0937-online-stock-span

Concurrency

1203-print-in-order

Binary Search Tree

0255-verify-preorder-sequence-in-binary-search-tree
0270-closest-binary-search-tree-value
0272-closest-binary-search-tree-value-ii
0333-largest-bst-subtree
0450-delete-node-in-a-bst
0783-search-in-a-binary-search-tree
1150-two-sum-bsts

Ordered Set

0716-max-stack
2413-smallest-number-in-infinite-set
2434-design-a-number-container-system
3791-fruits-into-baskets-iii

Interactive

0277-find-the-celebrity
0374-guess-number-higher-or-lower
1271-web-crawler
1672-find-the-index-of-the-large-integer

Combinatorics

0062-unique-paths

Divide and Conquer

0105-construct-binary-tree-from-preorder-and-inorder-traversal
0106-construct-binary-tree-from-inorder-and-postorder-traversal
0215-kth-largest-element-in-an-array
0347-top-k-frequent-elements
1014-k-closest-points-to-origin

Quickselect

0215-kth-largest-element-in-an-array
0347-top-k-frequent-elements
1014-k-closest-points-to-origin

Shortest Path

0399-evaluate-division
0499-the-maze-iii

Geometry

1014-k-closest-points-to-origin

Iterator

0281-zigzag-iterator
0604-design-compressed-string-iterator

Bucket Sort

0347-top-k-frequent-elements

Enumeration

2140-longest-subsequence-repeated-k-times
2170-count-number-of-maximum-bitwise-or-subsets
3751-maximum-frequency-after-subarray-operation

Doubly-Linked List

0146-lru-cache
0716-max-stack

Monotonic Queue

0239-sliding-window-maximum

Randomized

0380-insert-delete-getrandom-o1

Segment Tree

3791-fruits-into-baskets-iii

Number Theory

3949-minimum-number-of-primes-to-sum-to-target