leetcode-solutions

LeetCode Topics

Database

0175-combine-two-tables
0178-rank-scores
0180-consecutive-numbers
0181-employees-earning-more-than-their-managers
0184-department-highest-salary
0262-trips-and-users
0584-find-customer-referee
0585-investments-in-2016
0586-customer-placing-the-largest-number-of-orders
0596-classes-with-at-least-5-students
0601-human-traffic-of-stadium
0608-tree-node
0620-not-boring-movies
1045-customers-who-bought-all-products
1070-product-sales-analysis-iii
1141-user-activity-for-the-past-30-days-i
1193-monthly-transactions-i
1280-students-and-examinations
1341-movie-rating

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0041-first-missing-positive
0049-group-anagrams
0138-copy-list-with-random-pointer
0146-lru-cache
0347-top-k-frequent-elements
0352-data-stream-as-disjoint-intervals
0355-design-twitter
0380-insert-delete-getrandom-o1
0381-insert-delete-getrandom-o1-duplicates-allowed
0432-all-oone-data-structure
0448-find-all-numbers-disappeared-in-an-array
0460-lfu-cache
0560-subarray-sum-equals-k
0645-set-mismatch
1015-smallest-integer-divisible-by-k
1189-maximum-number-of-balloons
1358-number-of-substrings-containing-all-three-characters
1365-how-many-numbers-are-smaller-than-the-current-number
1386-cinema-seat-allocation
1590-make-sum-divisible-by-p
2043-simple-bank-system
2048-next-greater-numerically-balanced-number
2080-range-frequency-queries
3013-divide-an-array-into-subarrays-with-minimum-cost-ii
3020-find-the-maximum-number-of-elements-in-subset
3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii
3713-longest-balanced-substring-i
3719-longest-balanced-subarray-i
3737-count-subarrays-with-majority-element-i
3739-count-subarrays-with-majority-element-ii

Linked List

0002-add-two-numbers
0021-merge-two-sorted-lists
0023-merge-k-sorted-lists
0083-remove-duplicates-from-sorted-list
0138-copy-list-with-random-pointer
0146-lru-cache
0206-reverse-linked-list
0328-odd-even-linked-list
0355-design-twitter
0432-all-oone-data-structure
0460-lfu-cache
2095-delete-the-middle-node-of-a-linked-list
2130-maximum-twin-sum-of-a-linked-list
3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii

Design

0146-lru-cache
0155-min-stack
0232-implement-queue-using-stacks
0352-data-stream-as-disjoint-intervals
0355-design-twitter
0380-insert-delete-getrandom-o1
0381-insert-delete-getrandom-o1-duplicates-allowed
0432-all-oone-data-structure
0460-lfu-cache
0703-kth-largest-element-in-a-stream
0715-range-module
1032-stream-of-characters
1476-subrectangle-queries
2043-simple-bank-system
2080-range-frequency-queries

Doubly-Linked List

0146-lru-cache
0432-all-oone-data-structure
0460-lfu-cache
3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii

Array

0001-two-sum
0004-median-of-two-sorted-arrays
0041-first-missing-positive
0042-trapping-rain-water
0049-group-anagrams
0056-merge-intervals
0084-largest-rectangle-in-histogram
0085-maximal-rectangle
0121-best-time-to-buy-and-sell-stock
0150-evaluate-reverse-polish-notation
0152-maximum-product-subarray
0198-house-robber
0200-number-of-islands
0238-product-of-array-except-self
0239-sliding-window-maximum
0347-top-k-frequent-elements
0373-find-k-pairs-with-smallest-sums
0380-insert-delete-getrandom-o1
0381-insert-delete-getrandom-o1-duplicates-allowed
0448-find-all-numbers-disappeared-in-an-array
0485-max-consecutive-ones
0560-subarray-sum-equals-k
0636-exclusive-time-of-functions
0645-set-mismatch
0739-daily-temperatures
0744-find-smallest-letter-greater-than-target
0994-rotting-oranges
1004-max-consecutive-ones-iii
1032-stream-of-characters
1046-last-stone-weight
1200-minimum-absolute-difference
1292-maximum-side-length-of-a-square-with-sum-less-than-or-equal-to-threshold
1301-number-of-paths-with-max-score
1354-construct-target-array-with-multiple-sums
1365-how-many-numbers-are-smaller-than-the-current-number
1386-cinema-seat-allocation
1441-build-an-array-with-stack-operations
1470-shuffle-the-array
1475-final-prices-with-a-special-discount-in-a-shop
1476-subrectangle-queries
1502-can-make-arithmetic-progression-from-sequence
1590-make-sum-divisible-by-p
1664-ways-to-make-a-fair-array
1700-number-of-students-unable-to-eat-lunch
1732-find-the-highest-altitude
1833-maximum-ice-cream-bars
1840-maximum-building-height
1846-maximum-element-after-decreasing-and-rearranging
1877-minimize-maximum-pair-sum-in-array
1887-reduction-operations-to-make-the-array-elements-equal
1929-concatenation-of-array
1944-number-of-visible-people-in-a-queue
1967-number-of-strings-that-appear-as-substrings-in-word
1984-minimum-difference-between-highest-and-lowest-of-k-scores
1998-gcd-sort-of-an-array
2043-simple-bank-system
2073-time-needed-to-buy-tickets
2080-range-frequency-queries
2812-find-the-safest-path-in-a-grid
2976-minimum-cost-to-convert-string-i
2977-minimum-cost-to-convert-string-ii
3010-divide-an-array-into-subarrays-with-minimum-cost-i
3013-divide-an-array-into-subarrays-with-minimum-cost-ii
3020-find-the-maximum-number-of-elements-in-subset
3286-find-a-safe-walk-through-a-grid
3314-construct-the-minimum-bitwise-array-i
3315-construct-the-minimum-bitwise-array-ii
3379-transformed-array
3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii
3620-network-recovery-pathways
3634-minimum-removals-to-balance-array
3637-trionic-array-i
3651-minimum-cost-path-with-teleportations
3701-compute-alternating-sum
3719-longest-balanced-subarray-i
3737-count-subarrays-with-majority-element-i
3739-count-subarrays-with-majority-element-ii
3838-weighted-word-mapping

Simulation

1441-build-an-array-with-stack-operations
1700-number-of-students-unable-to-eat-lunch
1929-concatenation-of-array
2043-simple-bank-system
2073-time-needed-to-buy-tickets
3379-transformed-array
3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii
3612-process-string-with-special-operations-i
3614-process-string-with-special-operations-ii
3701-compute-alternating-sum
3838-weighted-word-mapping

Tree

0110-balanced-binary-tree
0703-kth-largest-element-in-a-stream
1339-maximum-product-of-splitted-binary-tree
1382-balance-a-binary-search-tree

Binary Search Tree

0004-median-of-two-sorted-arrays
0352-data-stream-as-disjoint-intervals
0703-kth-largest-element-in-a-stream
0744-find-smallest-letter-greater-than-target
1004-max-consecutive-ones-iii
1292-maximum-side-length-of-a-square-with-sum-less-than-or-equal-to-threshold
1382-balance-a-binary-search-tree
2080-range-frequency-queries
2812-find-the-safest-path-in-a-grid
3620-network-recovery-pathways
3634-minimum-removals-to-balance-array

Heap (Priority Queue)

0023-merge-k-sorted-lists
0239-sliding-window-maximum
0347-top-k-frequent-elements
0355-design-twitter
0373-find-k-pairs-with-smallest-sums
0703-kth-largest-element-in-a-stream
1046-last-stone-weight
1354-construct-target-array-with-multiple-sums
2812-find-the-safest-path-in-a-grid
3013-divide-an-array-into-subarrays-with-minimum-cost-ii
3286-find-a-safe-walk-through-a-grid
3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii
3620-network-recovery-pathways
3650-minimum-cost-path-with-edge-reversals

Binary Tree

0110-balanced-binary-tree
0703-kth-largest-element-in-a-stream
1339-maximum-product-of-splitted-binary-tree
1382-balance-a-binary-search-tree

Data Stream

0352-data-stream-as-disjoint-intervals
0703-kth-largest-element-in-a-stream
1032-stream-of-characters

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0006-zigzag-conversion
0008-string-to-integer-atoi
0020-valid-parentheses
0022-generate-parentheses
0049-group-anagrams
0459-repeated-substring-pattern
0482-license-key-formatting
0520-detect-capital
0686-repeated-string-match
0796-rotate-string
0831-masking-personal-information
1032-stream-of-characters
1189-maximum-number-of-balloons
1209-remove-all-adjacent-duplicates-in-string-ii
1249-minimum-remove-to-make-valid-parentheses
1358-number-of-substrings-containing-all-three-characters
1653-minimum-deletions-to-make-string-balanced
1967-number-of-strings-that-appear-as-substrings-in-word
2976-minimum-cost-to-convert-string-i
2977-minimum-cost-to-convert-string-ii
3612-process-string-with-special-operations-i
3614-process-string-with-special-operations-ii
3713-longest-balanced-substring-i
3838-weighted-word-mapping

Trie

1032-stream-of-characters
2977-minimum-cost-to-convert-string-ii

Union-Find

0200-number-of-islands
0352-data-stream-as-disjoint-intervals
1998-gcd-sort-of-an-array
2492-minimum-score-of-a-path-between-two-cities
2812-find-the-safest-path-in-a-grid

Ordered Set

0352-data-stream-as-disjoint-intervals
0715-range-module
3507-minimum-pair-removal-to-sort-array-i
3510-minimum-pair-removal-to-sort-array-ii

Sorting

0049-group-anagrams
0056-merge-intervals
0347-top-k-frequent-elements
0645-set-mismatch
1200-minimum-absolute-difference
1365-how-many-numbers-are-smaller-than-the-current-number
1502-can-make-arithmetic-progression-from-sequence
1833-maximum-ice-cream-bars
1840-maximum-building-height
1846-maximum-element-after-decreasing-and-rearranging
1877-minimize-maximum-pair-sum-in-array
1887-reduction-operations-to-make-the-array-elements-equal
1984-minimum-difference-between-highest-and-lowest-of-k-scores
1998-gcd-sort-of-an-array
3010-divide-an-array-into-subarrays-with-minimum-cost-i
3634-minimum-removals-to-balance-array

Two Pointers

0005-longest-palindromic-substring
0042-trapping-rain-water
1877-minimize-maximum-pair-sum-in-array
2095-delete-the-middle-node-of-a-linked-list
2130-maximum-twin-sum-of-a-linked-list

Stack

0020-valid-parentheses
0042-trapping-rain-water
0084-largest-rectangle-in-histogram
0085-maximal-rectangle
0150-evaluate-reverse-polish-notation
0155-min-stack
0232-implement-queue-using-stacks
0636-exclusive-time-of-functions
0739-daily-temperatures
1209-remove-all-adjacent-duplicates-in-string-ii
1249-minimum-remove-to-make-valid-parentheses
1441-build-an-array-with-stack-operations
1475-final-prices-with-a-special-discount-in-a-shop
1653-minimum-deletions-to-make-string-balanced
1700-number-of-students-unable-to-eat-lunch
1944-number-of-visible-people-in-a-queue
2130-maximum-twin-sum-of-a-linked-list

Math

0002-add-two-numbers
0007-reverse-integer
0009-palindrome-number
0150-evaluate-reverse-polish-notation
0263-ugly-number
0380-insert-delete-getrandom-o1
0381-insert-delete-getrandom-o1-duplicates-allowed
0728-self-dividing-numbers
1015-smallest-integer-divisible-by-k
1344-angle-between-hands-of-a-clock
1840-maximum-building-height
1998-gcd-sort-of-an-array
2048-next-greater-numerically-balanced-number
2485-find-the-pivot-integer
3700-number-of-zigzag-arrays-ii
3753-total-waviness-of-numbers-in-range-ii

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0206-reverse-linked-list

Sliding Window

0003-longest-substring-without-repeating-characters
0239-sliding-window-maximum
1004-max-consecutive-ones-iii
1358-number-of-substrings-containing-all-three-characters
1984-minimum-difference-between-highest-and-lowest-of-k-scores
3013-divide-an-array-into-subarrays-with-minimum-cost-ii
3634-minimum-removals-to-balance-array

Prefix Sum

0238-product-of-array-except-self
0560-subarray-sum-equals-k
1004-max-consecutive-ones-iii
1292-maximum-side-length-of-a-square-with-sum-less-than-or-equal-to-threshold
1590-make-sum-divisible-by-p
1664-ways-to-make-a-fair-array
1732-find-the-highest-altitude
2485-find-the-pivot-integer
3699-number-of-zigzag-arrays-i
3719-longest-balanced-subarray-i
3737-count-subarrays-with-majority-element-i
3739-count-subarrays-with-majority-element-ii

Matrix

0085-maximal-rectangle
0200-number-of-islands
0994-rotting-oranges
1292-maximum-side-length-of-a-square-with-sum-less-than-or-equal-to-threshold
1301-number-of-paths-with-max-score
1476-subrectangle-queries
2812-find-the-safest-path-in-a-grid
3286-find-a-safe-walk-through-a-grid
3651-minimum-cost-path-with-teleportations

Bit Manipulation

0645-set-mismatch
1386-cinema-seat-allocation
2571-minimum-operations-to-reduce-an-integer-to-0
3314-construct-the-minimum-bitwise-array-i
3315-construct-the-minimum-bitwise-array-ii

Greedy

1382-balance-a-binary-search-tree
1386-cinema-seat-allocation
1833-maximum-ice-cream-bars
1846-maximum-element-after-decreasing-and-rearranging
1877-minimize-maximum-pair-sum-in-array
2571-minimum-operations-to-reduce-an-integer-to-0

Counting Sort

0347-top-k-frequent-elements
1189-maximum-number-of-balloons
1365-how-many-numbers-are-smaller-than-the-current-number
1833-maximum-ice-cream-bars
2048-next-greater-numerically-balanced-number
3713-longest-balanced-substring-i
3737-count-subarrays-with-majority-element-i

Monotonic Stack

0042-trapping-rain-water
0084-largest-rectangle-in-histogram
0085-maximal-rectangle
0739-daily-temperatures
1475-final-prices-with-a-special-discount-in-a-shop
1944-number-of-visible-people-in-a-queue

Queue

0232-implement-queue-using-stacks
0239-sliding-window-maximum
1700-number-of-students-unable-to-eat-lunch
2073-time-needed-to-buy-tickets

String Matching

0459-repeated-substring-pattern
0686-repeated-string-match
0796-rotate-string

Graph Theory

0207-course-schedule
2492-minimum-score-of-a-path-between-two-cities
2858-minimum-edge-reversals-so-every-node-is-reachable
2976-minimum-cost-to-convert-string-i
2977-minimum-cost-to-convert-string-ii
3286-find-a-safe-walk-through-a-grid
3620-network-recovery-pathways
3650-minimum-cost-path-with-edge-reversals

Shortest Path

2976-minimum-cost-to-convert-string-i
2977-minimum-cost-to-convert-string-ii
3286-find-a-safe-walk-through-a-grid
3620-network-recovery-pathways
3650-minimum-cost-path-with-edge-reversals

Dynamic Programming

0005-longest-palindromic-substring
0022-generate-parentheses
0042-trapping-rain-water
0085-maximal-rectangle
0121-best-time-to-buy-and-sell-stock
0152-maximum-product-subarray
0198-house-robber
1269-number-of-ways-to-stay-in-the-same-place-after-some-steps
1301-number-of-paths-with-max-score
1653-minimum-deletions-to-make-string-balanced
2571-minimum-operations-to-reduce-an-integer-to-0
2858-minimum-edge-reversals-so-every-node-is-reachable
2977-minimum-cost-to-convert-string-ii
3620-network-recovery-pathways
3651-minimum-cost-path-with-teleportations
3699-number-of-zigzag-arrays-i
3700-number-of-zigzag-arrays-ii
3753-total-waviness-of-numbers-in-range-ii

Enumeration

2048-next-greater-numerically-balanced-number
3010-divide-an-array-into-subarrays-with-minimum-cost-i
3020-find-the-maximum-number-of-elements-in-subset
3713-longest-balanced-substring-i

Randomized

0380-insert-delete-getrandom-o1
0381-insert-delete-getrandom-o1-duplicates-allowed

Segment Tree

0715-range-module
2080-range-frequency-queries
3719-longest-balanced-subarray-i
3737-count-subarrays-with-majority-element-i
3739-count-subarrays-with-majority-element-ii

Divide and Conquer

0004-median-of-two-sorted-arrays
0023-merge-k-sorted-lists
0347-top-k-frequent-elements
1382-balance-a-binary-search-tree
3719-longest-balanced-subarray-i
3737-count-subarrays-with-majority-element-i
3739-count-subarrays-with-majority-element-ii

Merge Sort

0023-merge-k-sorted-lists
3737-count-subarrays-with-majority-element-i
3739-count-subarrays-with-majority-element-ii

Depth-First Search

0110-balanced-binary-tree
0200-number-of-islands
0207-course-schedule
1339-maximum-product-of-splitted-binary-tree
1382-balance-a-binary-search-tree
2492-minimum-score-of-a-path-between-two-cities
2858-minimum-edge-reversals-so-every-node-is-reachable

Breadth-First Search

0200-number-of-islands
0207-course-schedule
0994-rotting-oranges
2492-minimum-score-of-a-path-between-two-cities
2812-find-the-safest-path-in-a-grid
2858-minimum-edge-reversals-so-every-node-is-reachable
3286-find-a-safe-walk-through-a-grid

Backtracking

0022-generate-parentheses
2048-next-greater-numerically-balanced-number

Topological Sort

0207-course-schedule
3620-network-recovery-pathways

Bucket Sort

0347-top-k-frequent-elements

Quickselect

0347-top-k-frequent-elements

Monotonic Queue

0239-sliding-window-maximum

Number Theory

1998-gcd-sort-of-an-array