Leetcode

LeetCode Topics

Array

0001-two-sum
0004-median-of-two-sorted-arrays
0011-container-with-most-water
0015-3sum
0026-remove-duplicates-from-sorted-array
0031-next-permutation
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0041-first-missing-positive
0048-rotate-image
0049-group-anagrams
0053-maximum-subarray
0054-spiral-matrix
0056-merge-intervals
0063-unique-paths-ii
0066-plus-one
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0075-sort-colors
0084-largest-rectangle-in-histogram
0088-merge-sorted-array
0118-pascals-triangle
0121-best-time-to-buy-and-sell-stock
0135-candy
0136-single-number
0149-max-points-on-a-line
0150-evaluate-reverse-polish-notation
0152-maximum-product-subarray
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0169-majority-element
0179-largest-number
0189-rotate-array
0209-minimum-size-subarray-sum
0217-contains-duplicate
0219-contains-duplicate-ii
0229-majority-element-ii
0238-product-of-array-except-self
0239-sliding-window-maximum
0283-move-zeroes
0287-find-the-duplicate-number
0334-increasing-triplet-subsequence
0349-intersection-of-two-arrays
0376-wiggle-subsequence
0378-kth-smallest-element-in-a-sorted-matrix
0410-split-array-largest-sum
0455-assign-cookies
0485-max-consecutive-ones
0496-next-greater-element-i
0503-next-greater-element-ii
0525-contiguous-array
0532-k-diff-pairs-in-an-array
0540-single-element-in-a-sorted-array
0560-subarray-sum-equals-k
0598-range-addition-ii
0643-maximum-average-subarray-i
0713-subarray-product-less-than-k
0724-find-pivot-index
0790-global-and-local-inversions
0817-design-hashmap
0837-most-common-word
0860-design-circular-queue
0987-reveal-cards-in-increasing-order
1034-subarrays-with-k-different-integers
1046-max-consecutive-ones-iii
1056-capacity-to-ship-packages-within-d-days
1305-number-of-visible-people-in-a-queue
1319-unique-number-of-occurrences
1402-count-square-submatrices-with-all-ones
1408-find-the-smallest-divisor-given-a-threshold
1476-count-negative-numbers-in-a-sorted-matrix
1510-find-lucky-integer-in-an-array
1580-shuffle-the-array
1584-average-salary-excluding-the-minimum-and-maximum-salary
1586-longest-subarray-of-1s-after-deleting-one-element
1603-running-sum-of-1d-array
1635-number-of-good-pairs
1651-shuffle-string
1693-sum-of-all-odd-length-subarrays
1720-crawler-log-folder
1741-sort-array-by-increasing-frequency
1783-ways-to-make-a-fair-array
1791-richest-customer-wealth
1802-number-of-students-unable-to-eat-lunch
1833-find-the-highest-altitude
1848-sum-of-unique-elements
1878-check-if-array-is-sorted-and-rotated
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1925-count-nice-pairs-in-an-array
1984-maximum-distance-between-a-pair-of-values
1988-minimize-maximum-pair-sum-in-array
1993-sum-of-all-subset-xor-totals
2042-maximum-product-difference-between-two-pairs
2048-build-array-from-permutation
2058-concatenation-of-array
2066-add-minimum-number-of-rungs
2116-count-number-of-pairs-with-absolute-difference-k
2137-final-value-of-variable-after-performing-operations
2144-maximum-difference-between-increasing-elements
2181-smallest-index-with-equal-value
2215-finding-3-digit-even-numbers
2219-maximum-number-of-words-found-in-sentences
2231-find-first-palindromic-string-in-the-array
2525-count-number-of-distinct-integers-after-reverse-operations
2536-determine-if-two-events-have-conflict
2542-average-value-of-even-numbers-that-are-divisible-by-three
2847-find-maximum-number-of-string-pairs
2876-number-of-employees-who-met-the-target
3194-find-words-containing-character
3747-maximum-difference-between-adjacent-elements-in-a-circular-array

Math

0013-roman-to-integer
0048-rotate-image
0050-powx-n
0066-plus-one
0067-add-binary
0070-climbing-stairs
0089-gray-code
0149-max-points-on-a-line
0150-evaluate-reverse-polish-notation
0189-rotate-array
0367-valid-perfect-square
0412-fizz-buzz
0598-range-addition-ii
0767-prime-number-of-set-bits-in-binary-representation
0790-global-and-local-inversions
1013-fibonacci-number
1048-clumsy-factorial
1146-greatest-common-divisor-of-strings
1406-subtract-the-product-and-sum-of-digits-of-an-integer
1411-convert-binary-number-in-a-linked-list-to-integer
1444-number-of-steps-to-reduce-a-number-to-zero
1448-maximum-69-number
1585-the-kth-factor-of-n
1610-xor-operation-in-an-array
1635-number-of-good-pairs
1674-minimum-operations-to-make-array-equal
1693-sum-of-all-odd-length-subarrays
1806-count-of-matches-in-tournament
1817-calculate-money-in-leetcode-bank
1844-maximum-number-of-balls-in-a-box
1889-check-if-number-is-a-sum-of-powers-of-three
1925-count-nice-pairs-in-an-array
1993-sum-of-all-subset-xor-totals
2383-add-two-integers
2491-smallest-even-multiple
2525-count-number-of-distinct-integers-after-reverse-operations
2542-average-value-of-even-numbers-that-are-divisible-by-three
2556-convert-the-temperature
2571-find-the-pivot-integer
2608-count-the-digits-that-divide-a-number
2752-sum-multiples
2812-find-the-maximum-achievable-number
2903-insert-greatest-common-divisors-in-linked-list
2998-count-symmetric-integers
3172-divisible-and-non-divisible-sums-difference
3371-harshad-number

String

0003-longest-substring-without-repeating-characters
0006-zigzag-conversion
0013-roman-to-integer
0014-longest-common-prefix
0020-valid-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string
0038-count-and-say
0049-group-anagrams
0067-add-binary
0076-minimum-window-substring
0125-valid-palindrome
0151-reverse-words-in-a-string
0179-largest-number
0242-valid-anagram
0257-binary-tree-paths
0297-serialize-and-deserialize-binary-tree
0344-reverse-string
0387-first-unique-character-in-a-string
0412-fizz-buzz
0438-find-all-anagrams-in-a-string
0696-count-binary-substrings
0782-jewels-and-stones
0837-most-common-word
1078-remove-outermost-parentheses
1128-remove-all-adjacent-duplicates-in-string
1146-greatest-common-divisor-of-strings
1205-defanging-an-ip-address
1302-delete-characters-to-make-fancy-string
1320-remove-all-adjacent-duplicates-in-string-ii
1341-split-a-string-in-balanced-strings
1469-minimum-number-of-steps-to-make-two-strings-anagram
1651-shuffle-string
1666-make-the-string-great
1720-crawler-log-folder
1777-determine-if-two-strings-are-close
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
1904-second-largest-digit-in-a-string
2128-reverse-prefix-of-word
2137-final-value-of-variable-after-performing-operations
2154-minimum-moves-to-convert-string
2219-maximum-number-of-words-found-in-sentences
2231-find-first-palindromic-string-in-the-array
2536-determine-if-two-events-have-conflict
2580-circular-sentence
2847-find-maximum-number-of-string-pairs
3194-find-words-containing-character
3379-score-of-a-string
3412-permutation-difference-between-two-strings

Binary Search

0004-median-of-two-sorted-arrays
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0074-search-a-2d-matrix
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0209-minimum-size-subarray-sum
0278-first-bad-version
0287-find-the-duplicate-number
0349-intersection-of-two-arrays
0367-valid-perfect-square
0374-guess-number-higher-or-lower
0378-kth-smallest-element-in-a-sorted-matrix
0410-split-array-largest-sum
0532-k-diff-pairs-in-an-array
0540-single-element-in-a-sorted-array
0713-subarray-product-less-than-k
1046-max-consecutive-ones-iii
1056-capacity-to-ship-packages-within-d-days
1408-find-the-smallest-divisor-given-a-threshold
1476-count-negative-numbers-in-a-sorted-matrix
1984-maximum-distance-between-a-pair-of-values

Database

0175-combine-two-tables
0176-second-highest-salary
0177-nth-highest-salary
0178-rank-scores
0180-consecutive-numbers
0181-employees-earning-more-than-their-managers
0182-duplicate-emails
0183-customers-who-never-order
0184-department-highest-salary
0185-department-top-three-salaries
0196-delete-duplicate-emails
0197-rising-temperature
0570-managers-with-at-least-5-direct-reports
0577-employee-bonus
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
0602-friend-requests-ii-who-has-the-most-friends
0607-sales-person
0608-tree-node
0610-triangle-judgement
0619-biggest-single-number
0620-not-boring-movies
0626-exchange-seats
0627-swap-salary
1135-customers-who-bought-all-products
1136-actors-and-directors-who-cooperated-at-least-three-times
1153-product-sales-analysis-i
1155-product-sales-analysis-iii
1161-project-employees-i
1174-sales-analysis-iii
1179-game-play-analysis-i
1182-game-play-analysis-iv
1245-user-activity-for-the-past-30-days-i
1258-article-views-i
1268-market-analysis-i
1292-immediate-food-delivery-ii
1317-monthly-transactions-i
1390-average-selling-price
1415-students-and-examinations
1452-restaurant-growth
1480-movie-rating
1509-replace-employee-id-with-the-unique-identifier
1523-capital-gainloss
1625-group-sold-products-by-the-date
1670-patients-with-a-condition
1724-customer-who-visited-but-did-not-make-any-transactions
1801-average-time-of-process-per-machine
1811-fix-names-in-a-table
1827-invalid-tweets
1837-daily-leads-and-partners
1877-find-followers-count
1892-find-total-time-spent-by-each-employee
1908-recyclable-and-low-fat-products
2087-confirmation-rate
2110-employees-with-missing-information
2495-number-of-unique-subjects-taught-by-each-teacher
3530-odd-and-even-transactions
3767-find-students-who-improved
3816-dna-pattern-recognition
3848-analyze-subscription-conversion
3898-seasonal-sales-analysis

Bit Manipulation

0067-add-binary
0089-gray-code
0136-single-number
0287-find-the-duplicate-number
0767-prime-number-of-set-bits-in-binary-representation
1444-number-of-steps-to-reduce-a-number-to-zero
1610-xor-operation-in-an-array
1993-sum-of-all-subset-xor-totals

Simulation

0054-spiral-matrix
0067-add-binary
0412-fizz-buzz
0987-reveal-cards-in-increasing-order
1048-clumsy-factorial
1802-number-of-students-unable-to-eat-lunch
1806-count-of-matches-in-tournament
2048-build-array-from-permutation
2058-concatenation-of-array
2137-final-value-of-variable-after-performing-operations
2847-find-maximum-number-of-string-pairs

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0013-roman-to-integer
0041-first-missing-positive
0049-group-anagrams
0073-set-matrix-zeroes
0076-minimum-window-substring
0138-copy-list-with-random-pointer
0141-linked-list-cycle
0142-linked-list-cycle-ii
0149-max-points-on-a-line
0160-intersection-of-two-linked-lists
0169-majority-element
0217-contains-duplicate
0219-contains-duplicate-ii
0229-majority-element-ii
0242-valid-anagram
0349-intersection-of-two-arrays
0387-first-unique-character-in-a-string
0438-find-all-anagrams-in-a-string
0496-next-greater-element-i
0525-contiguous-array
0532-k-diff-pairs-in-an-array
0560-subarray-sum-equals-k
0782-jewels-and-stones
0817-design-hashmap
0837-most-common-word
0931-maximum-frequency-stack
1034-subarrays-with-k-different-integers
1319-unique-number-of-occurrences
1469-minimum-number-of-steps-to-make-two-strings-anagram
1510-find-lucky-integer-in-an-array
1635-number-of-good-pairs
1741-sort-array-by-increasing-frequency
1777-determine-if-two-strings-are-close
1844-maximum-number-of-balls-in-a-box
1848-sum-of-unique-elements
1904-second-largest-digit-in-a-string
1925-count-nice-pairs-in-an-array
2116-count-number-of-pairs-with-absolute-difference-k
2215-finding-3-digit-even-numbers
2525-count-number-of-distinct-integers-after-reverse-operations
2847-find-maximum-number-of-string-pairs
3412-permutation-difference-between-two-strings

Counting

0169-majority-element
0229-majority-element-ii
0387-first-unique-character-in-a-string
0837-most-common-word
1034-subarrays-with-k-different-integers
1341-split-a-string-in-balanced-strings
1469-minimum-number-of-steps-to-make-two-strings-anagram
1510-find-lucky-integer-in-an-array
1635-number-of-good-pairs
1777-determine-if-two-strings-are-close
1844-maximum-number-of-balls-in-a-box
1848-sum-of-unique-elements
1925-count-nice-pairs-in-an-array
2116-count-number-of-pairs-with-absolute-difference-k
2525-count-number-of-distinct-integers-after-reverse-operations

Matrix

0048-rotate-image
0054-spiral-matrix
0063-unique-paths-ii
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0378-kth-smallest-element-in-a-sorted-matrix
1402-count-square-submatrices-with-all-ones
1476-count-negative-numbers-in-a-sorted-matrix
1791-richest-customer-wealth

Backtracking

0089-gray-code
0257-binary-tree-paths
1993-sum-of-all-subset-xor-totals

Combinatorics

1993-sum-of-all-subset-xor-totals

Enumeration

1993-sum-of-all-subset-xor-totals
2215-finding-3-digit-even-numbers
2998-count-symmetric-integers

Two Pointers

0011-container-with-most-water
0015-3sum
0019-remove-nth-node-from-end-of-list
0026-remove-duplicates-from-sorted-array
0028-find-the-index-of-the-first-occurrence-in-a-string
0031-next-permutation
0061-rotate-list
0075-sort-colors
0088-merge-sorted-array
0125-valid-palindrome
0141-linked-list-cycle
0142-linked-list-cycle-ii
0143-reorder-list
0151-reverse-words-in-a-string
0160-intersection-of-two-linked-lists
0167-two-sum-ii-input-array-is-sorted
0189-rotate-array
0283-move-zeroes
0287-find-the-duplicate-number
0344-reverse-string
0349-intersection-of-two-arrays
0455-assign-cookies
0532-k-diff-pairs-in-an-array
0696-count-binary-substrings
0908-middle-of-the-linked-list
1984-maximum-distance-between-a-pair-of-values
1988-minimize-maximum-pair-sum-in-array
2128-reverse-prefix-of-word
2231-find-first-palindromic-string-in-the-array

Sorting

0015-3sum
0049-group-anagrams
0056-merge-intervals
0075-sort-colors
0088-merge-sorted-array
0147-insertion-sort-list
0169-majority-element
0179-largest-number
0217-contains-duplicate
0229-majority-element-ii
0242-valid-anagram
0349-intersection-of-two-arrays
0378-kth-smallest-element-in-a-sorted-matrix
0455-assign-cookies
0532-k-diff-pairs-in-an-array
0987-reveal-cards-in-increasing-order
1584-average-salary-excluding-the-minimum-and-maximum-salary
1741-sort-array-by-increasing-frequency
1777-determine-if-two-strings-are-close
1988-minimize-maximum-pair-sum-in-array
2042-maximum-product-difference-between-two-pairs
2215-finding-3-digit-even-numbers

Divide and Conquer

0004-median-of-two-sorted-arrays
0023-merge-k-sorted-lists
0053-maximum-subarray
0169-majority-element

Trie

0014-longest-common-prefix

Linked List

0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0023-merge-k-sorted-lists
0025-reverse-nodes-in-k-group
0061-rotate-list
0083-remove-duplicates-from-sorted-list
0092-reverse-linked-list-ii
0138-copy-list-with-random-pointer
0141-linked-list-cycle
0142-linked-list-cycle-ii
0143-reorder-list
0147-insertion-sort-list
0160-intersection-of-two-linked-lists
0203-remove-linked-list-elements
0206-reverse-linked-list
0237-delete-node-in-a-linked-list
0328-odd-even-linked-list
0817-design-hashmap
0860-design-circular-queue
0908-middle-of-the-linked-list
1411-convert-binary-number-in-a-linked-list-to-integer
2903-insert-greatest-common-divisors-in-linked-list

Recursion

0021-merge-two-sorted-lists
0025-reverse-nodes-in-k-group
0050-powx-n
0143-reorder-list
0203-remove-linked-list-elements
0206-reverse-linked-list
1013-fibonacci-number

Greedy

0011-container-with-most-water
0135-candy
0179-largest-number
0334-increasing-triplet-subsequence
0376-wiggle-subsequence
0410-split-array-largest-sum
0455-assign-cookies
1341-split-a-string-in-balanced-strings
1448-maximum-69-number
1988-minimize-maximum-pair-sum-in-array
2066-add-minimum-number-of-rungs
2154-minimum-moves-to-convert-string

Stack

0020-valid-parentheses
0084-largest-rectangle-in-histogram
0094-binary-tree-inorder-traversal
0143-reorder-list
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0150-evaluate-reverse-polish-notation
0155-min-stack
0232-implement-queue-using-stacks
0496-next-greater-element-i
0503-next-greater-element-ii
0931-maximum-frequency-stack
1048-clumsy-factorial
1078-remove-outermost-parentheses
1128-remove-all-adjacent-duplicates-in-string
1305-number-of-visible-people-in-a-queue
1320-remove-all-adjacent-duplicates-in-string-ii
1666-make-the-string-great
1720-crawler-log-folder
1802-number-of-students-unable-to-eat-lunch

Prefix Sum

0209-minimum-size-subarray-sum
0238-product-of-array-except-self
0410-split-array-largest-sum
0525-contiguous-array
0560-subarray-sum-equals-k
0713-subarray-product-less-than-k
0724-find-pivot-index
1046-max-consecutive-ones-iii
1603-running-sum-of-1d-array
1693-sum-of-all-odd-length-subarrays
1783-ways-to-make-a-fair-array
1833-find-the-highest-altitude
1895-minimum-number-of-operations-to-move-all-balls-to-each-box
2571-find-the-pivot-integer

Number Theory

1585-the-kth-factor-of-n
2491-smallest-even-multiple
2903-insert-greatest-common-divisors-in-linked-list

Monotonic Stack

0084-largest-rectangle-in-histogram
0496-next-greater-element-i
0503-next-greater-element-ii
1305-number-of-visible-people-in-a-queue

Design

0155-min-stack
0232-implement-queue-using-stacks
0297-serialize-and-deserialize-binary-tree
0817-design-hashmap
0860-design-circular-queue
0931-maximum-frequency-stack

Dynamic Programming

0053-maximum-subarray
0063-unique-paths-ii
0070-climbing-stairs
0118-pascals-triangle
0121-best-time-to-buy-and-sell-stock
0152-maximum-product-subarray
0376-wiggle-subsequence
0410-split-array-largest-sum
1013-fibonacci-number
1402-count-square-submatrices-with-all-ones
1586-longest-subarray-of-1s-after-deleting-one-element

Memoization

0070-climbing-stairs
1013-fibonacci-number

Sliding Window

0003-longest-substring-without-repeating-characters
0076-minimum-window-substring
0209-minimum-size-subarray-sum
0219-contains-duplicate-ii
0239-sliding-window-maximum
0438-find-all-anagrams-in-a-string
0643-maximum-average-subarray-i
0713-subarray-product-less-than-k
1034-subarrays-with-k-different-integers
1046-max-consecutive-ones-iii
1586-longest-subarray-of-1s-after-deleting-one-element

Queue

0232-implement-queue-using-stacks
0239-sliding-window-maximum
0387-first-unique-character-in-a-string
0860-design-circular-queue
0987-reveal-cards-in-increasing-order
1802-number-of-students-unable-to-eat-lunch

Heap (Priority Queue)

0023-merge-k-sorted-lists
0239-sliding-window-maximum
0378-kth-smallest-element-in-a-sorted-matrix

Monotonic Queue

0239-sliding-window-maximum

Tree

0094-binary-tree-inorder-traversal
0100-same-tree
0101-symmetric-tree
0102-binary-tree-level-order-traversal
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0226-invert-binary-tree
0236-lowest-common-ancestor-of-a-binary-tree
0257-binary-tree-paths
0297-serialize-and-deserialize-binary-tree
0543-diameter-of-binary-tree
0784-insert-into-a-binary-search-tree

Depth-First Search

0094-binary-tree-inorder-traversal
0100-same-tree
0101-symmetric-tree
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0226-invert-binary-tree
0236-lowest-common-ancestor-of-a-binary-tree
0257-binary-tree-paths
0297-serialize-and-deserialize-binary-tree
0543-diameter-of-binary-tree

Binary Tree

0094-binary-tree-inorder-traversal
0100-same-tree
0101-symmetric-tree
0102-binary-tree-level-order-traversal
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0226-invert-binary-tree
0236-lowest-common-ancestor-of-a-binary-tree
0257-binary-tree-paths
0297-serialize-and-deserialize-binary-tree
0543-diameter-of-binary-tree
0784-insert-into-a-binary-search-tree

Breadth-First Search

0100-same-tree
0101-symmetric-tree
0102-binary-tree-level-order-traversal
0226-invert-binary-tree
0297-serialize-and-deserialize-binary-tree

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string

Interactive

0278-first-bad-version
0374-guess-number-higher-or-lower

Ordered Set

0931-maximum-frequency-stack

Geometry

0149-max-points-on-a-line

Hash Function

0817-design-hashmap

Binary Search Tree

0784-insert-into-a-binary-search-tree

Merge Sort

0023-merge-k-sorted-lists