Leetcode

LeetCode Topics

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0006-zigzag-conversion
0012-integer-to-roman
0014-longest-common-prefix
0017-letter-combinations-of-a-phone-number
0022-generate-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string
0038-count-and-say
0043-multiply-strings
0049-group-anagrams
0058-length-of-last-word
0067-add-binary
0071-simplify-path
0125-valid-palindrome
0151-reverse-words-in-a-string
0168-excel-sheet-column-title
0171-excel-sheet-column-number
0179-largest-number
0242-valid-anagram
0257-binary-tree-paths
0290-word-pattern
0344-reverse-string
0345-reverse-vowels-of-a-string
0383-ransom-note
0387-first-unique-character-in-a-string
0389-find-the-difference
0392-is-subsequence
0409-longest-palindrome
0412-fizz-buzz
0415-add-strings
0434-number-of-segments-in-a-string
0459-repeated-substring-pattern
0482-license-key-formatting
0500-keyboard-row
0504-base-7
0520-detect-capital
0521-longest-uncommon-subsequence-i
0541-reverse-string-ii
0551-student-attendance-record-i
0557-reverse-words-in-a-string-iii
0599-minimum-index-sum-of-two-lists
0657-robot-return-to-origin
0680-valid-palindrome-ii
0696-count-binary-substrings
0742-to-lower-case
0782-jewels-and-stones
0824-number-of-lines-to-write-string
0837-most-common-word
0841-shortest-distance-to-a-character
0965-unique-email-addresses
1078-remove-outermost-parentheses
1666-make-the-string-great
2128-reverse-prefix-of-word

Trie

0014-longest-common-prefix

Math

0007-reverse-integer
0012-integer-to-roman
0029-divide-two-integers
0043-multiply-strings
0050-powx-n
0066-plus-one
0067-add-binary
0069-sqrtx
0070-climbing-stairs
0168-excel-sheet-column-title
0171-excel-sheet-column-number
0189-rotate-array
0204-count-primes
0231-power-of-two
0258-add-digits
0263-ugly-number
0268-missing-number
0292-nim-game
0326-power-of-three
0342-power-of-four
0367-valid-perfect-square
0405-convert-a-number-to-hexadecimal
0412-fizz-buzz
0415-add-strings
0441-arranging-coins
0492-construct-the-rectangle
0504-base-7
0507-perfect-number
0598-range-addition-ii
0628-maximum-product-of-three-numbers
0728-self-dividing-numbers
0830-largest-triangle-area
1013-fibonacci-number

Bit Manipulation

0029-divide-two-integers
0067-add-binary
0078-subsets
0136-single-number
0190-reverse-bits
0191-number-of-1-bits
0231-power-of-two
0268-missing-number
0338-counting-bits
0342-power-of-four
0389-find-the-difference
0401-binary-watch
0405-convert-a-number-to-hexadecimal
0461-hamming-distance
0476-number-complement
0645-set-mismatch
0693-binary-number-with-alternating-bits

Array

0004-median-of-two-sorted-arrays
0011-container-with-most-water
0015-3sum
0016-3sum-closest
0018-4sum
0026-remove-duplicates-from-sorted-array
0027-remove-element
0031-next-permutation
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0035-search-insert-position
0036-valid-sudoku
0046-permutations
0049-group-anagrams
0054-spiral-matrix
0057-insert-interval
0066-plus-one
0073-set-matrix-zeroes
0075-sort-colors
0078-subsets
0080-remove-duplicates-from-sorted-array-ii
0088-merge-sorted-array
0108-convert-sorted-array-to-binary-search-tree
0118-pascals-triangle
0119-pascals-triangle-ii
0121-best-time-to-buy-and-sell-stock
0136-single-number
0169-majority-element
0179-largest-number
0189-rotate-array
0204-count-primes
0217-contains-duplicate
0219-contains-duplicate-ii
0228-summary-ranges
0268-missing-number
0283-move-zeroes
0303-range-sum-query-immutable
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0414-third-maximum-number
0448-find-all-numbers-disappeared-in-an-array
0455-assign-cookies
0463-island-perimeter
0485-max-consecutive-ones
0495-teemo-attacking
0496-next-greater-element-i
0500-keyboard-row
0506-relative-ranks
0561-array-partition
0566-reshape-the-matrix
0575-distribute-candies
0594-longest-harmonious-subsequence
0598-range-addition-ii
0599-minimum-index-sum-of-two-lists
0605-can-place-flowers
0628-maximum-product-of-three-numbers
0643-maximum-average-subarray-i
0645-set-mismatch
0661-image-smoother
0674-longest-continuous-increasing-subsequence
0682-baseball-game
0697-degree-of-an-array
0717-1-bit-and-2-bit-characters
0724-find-pivot-index
0745-find-smallest-letter-greater-than-target
0747-min-cost-climbing-stairs
0748-largest-number-at-least-twice-of-others
0824-number-of-lines-to-write-string
0830-largest-triangle-area
0837-most-common-word
0841-shortest-distance-to-a-character
0932-monotonic-array
0965-unique-email-addresses
2112-minimum-difference-between-highest-and-lowest-of-k-scores
2148-minimum-number-of-moves-to-seat-everyone
2283-sort-even-and-odd-indices-independently

Two Pointers

0005-longest-palindromic-substring
0011-container-with-most-water
0015-3sum
0016-3sum-closest
0018-4sum
0019-remove-nth-node-from-end-of-list
0026-remove-duplicates-from-sorted-array
0027-remove-element
0028-find-the-index-of-the-first-occurrence-in-a-string
0031-next-permutation
0075-sort-colors
0080-remove-duplicates-from-sorted-array-ii
0088-merge-sorted-array
0125-valid-palindrome
0141-linked-list-cycle
0151-reverse-words-in-a-string
0160-intersection-of-two-linked-lists
0189-rotate-array
0234-palindrome-linked-list
0283-move-zeroes
0344-reverse-string
0345-reverse-vowels-of-a-string
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0392-is-subsequence
0455-assign-cookies
0541-reverse-string-ii
0557-reverse-words-in-a-string-iii
0653-two-sum-iv-input-is-a-bst
0680-valid-palindrome-ii
0696-count-binary-substrings
0841-shortest-distance-to-a-character
2128-reverse-prefix-of-word

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string
0459-repeated-substring-pattern
0572-subtree-of-another-tree

Sorting

0015-3sum
0016-3sum-closest
0018-4sum
0049-group-anagrams
0075-sort-colors
0088-merge-sorted-array
0169-majority-element
0179-largest-number
0217-contains-duplicate
0242-valid-anagram
0268-missing-number
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0389-find-the-difference
0414-third-maximum-number
0455-assign-cookies
0506-relative-ranks
0561-array-partition
0594-longest-harmonious-subsequence
0628-maximum-product-of-three-numbers
0645-set-mismatch
0748-largest-number-at-least-twice-of-others
2112-minimum-difference-between-highest-and-lowest-of-k-scores
2148-minimum-number-of-moves-to-seat-everyone
2283-sort-even-and-odd-indices-independently

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
0069-sqrtx
0268-missing-number
0278-first-bad-version
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0367-valid-perfect-square
0374-guess-number-higher-or-lower
0441-arranging-coins
0745-find-smallest-letter-greater-than-target

Dynamic Programming

0005-longest-palindromic-substring
0022-generate-parentheses
0070-climbing-stairs
0118-pascals-triangle
0119-pascals-triangle-ii
0121-best-time-to-buy-and-sell-stock
0338-counting-bits
0392-is-subsequence
0747-min-cost-climbing-stairs
1013-fibonacci-number

Enumeration

0204-count-primes

Number Theory

0204-count-primes
0258-add-digits

Recursion

0050-powx-n
0203-remove-linked-list-elements
0206-reverse-linked-list
0231-power-of-two
0234-palindrome-linked-list
0326-power-of-three
0342-power-of-four
1013-fibonacci-number

Linked List

0019-remove-nth-node-from-end-of-list
0083-remove-duplicates-from-sorted-list
0141-linked-list-cycle
0160-intersection-of-two-linked-lists
0203-remove-linked-list-elements
0206-reverse-linked-list
0234-palindrome-linked-list

Hash Table

0003-longest-substring-without-repeating-characters
0012-integer-to-roman
0017-letter-combinations-of-a-phone-number
0036-valid-sudoku
0049-group-anagrams
0073-set-matrix-zeroes
0141-linked-list-cycle
0160-intersection-of-two-linked-lists
0169-majority-element
0217-contains-duplicate
0219-contains-duplicate-ii
0242-valid-anagram
0268-missing-number
0290-word-pattern
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0383-ransom-note
0387-first-unique-character-in-a-string
0389-find-the-difference
0409-longest-palindrome
0448-find-all-numbers-disappeared-in-an-array
0496-next-greater-element-i
0500-keyboard-row
0575-distribute-candies
0594-longest-harmonious-subsequence
0599-minimum-index-sum-of-two-lists
0645-set-mismatch
0653-two-sum-iv-input-is-a-bst
0697-degree-of-an-array
0782-jewels-and-stones
0837-most-common-word
0965-unique-email-addresses

Sliding Window

0003-longest-substring-without-repeating-characters
0219-contains-duplicate-ii
0594-longest-harmonious-subsequence
0643-maximum-average-subarray-i
2112-minimum-difference-between-highest-and-lowest-of-k-scores

Stack

0071-simplify-path
0094-binary-tree-inorder-traversal
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0234-palindrome-linked-list
0496-next-greater-element-i
0682-baseball-game
0775-n-ary-tree-preorder-traversal
0776-n-ary-tree-postorder-traversal
1078-remove-outermost-parentheses
1666-make-the-string-great
2128-reverse-prefix-of-word

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
0262-trips-and-users
0570-managers-with-at-least-5-direct-reports
0584-find-customer-referee
0585-investments-in-2016
0586-customer-placing-the-largest-number-of-orders
0595-big-countries
0596-classes-with-at-least-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
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
1278-product-price-at-a-given-date
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
1390-average-selling-price
1415-students-and-examinations
1452-restaurant-growth
1462-list-the-products-ordered-in-a-period
1480-movie-rating
1509-replace-employee-id-with-the-unique-identifier
1523-capital-gainloss
1541-top-travellers
1625-group-sold-products-by-the-date
1664-find-users-with-valid-e-mails
1670-patients-with-a-condition
1724-customer-who-visited-but-did-not-make-any-transactions
1734-bank-account-summary-ii
1773-percentage-of-users-attended-a-contest
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
1882-the-number-of-employees-which-report-to-each-employee
1892-find-total-time-spent-by-each-employee
1948-rearrange-products-table
2024-calculate-special-bonus
2041-the-latest-login-in-2020
2057-count-salary-categories
2110-employees-with-missing-information
3782-find-valid-emails
3803-find-products-with-valid-serial-numbers
3910-find-books-with-no-available-copies

Simulation

0043-multiply-strings
0054-spiral-matrix
0067-add-binary
0258-add-digits
0412-fizz-buzz
0415-add-strings
0495-teemo-attacking
0566-reshape-the-matrix
0657-robot-return-to-origin
0682-baseball-game

Memoization

0070-climbing-stairs
1013-fibonacci-number

Divide and Conquer

0004-median-of-two-sorted-arrays
0108-convert-sorted-array-to-binary-search-tree
0169-majority-element
0190-reverse-bits
0191-number-of-1-bits

Backtracking

0017-letter-combinations-of-a-phone-number
0022-generate-parentheses
0046-permutations
0078-subsets
0257-binary-tree-paths
0401-binary-watch

Greedy

0011-container-with-most-water
0179-largest-number
0409-longest-palindrome
0455-assign-cookies
0561-array-partition
0605-can-place-flowers
0680-valid-palindrome-ii
2148-minimum-number-of-moves-to-seat-everyone

Matrix

0036-valid-sudoku
0054-spiral-matrix
0073-set-matrix-zeroes
0463-island-perimeter
0566-reshape-the-matrix
0661-image-smoother

Tree

0094-binary-tree-inorder-traversal
0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0108-convert-sorted-array-to-binary-search-tree
0110-balanced-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0226-invert-binary-tree
0257-binary-tree-paths
0404-sum-of-left-leaves
0501-find-mode-in-binary-search-tree
0530-minimum-absolute-difference-in-bst
0563-binary-tree-tilt
0572-subtree-of-another-tree
0617-merge-two-binary-trees
0637-average-of-levels-in-binary-tree
0653-two-sum-iv-input-is-a-bst
0671-second-minimum-node-in-a-binary-tree
0774-maximum-depth-of-n-ary-tree
0775-n-ary-tree-preorder-traversal
0776-n-ary-tree-postorder-traversal

Depth-First Search

0094-binary-tree-inorder-traversal
0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0110-balanced-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0226-invert-binary-tree
0257-binary-tree-paths
0404-sum-of-left-leaves
0463-island-perimeter
0501-find-mode-in-binary-search-tree
0530-minimum-absolute-difference-in-bst
0563-binary-tree-tilt
0572-subtree-of-another-tree
0617-merge-two-binary-trees
0637-average-of-levels-in-binary-tree
0653-two-sum-iv-input-is-a-bst
0671-second-minimum-node-in-a-binary-tree
0774-maximum-depth-of-n-ary-tree
0775-n-ary-tree-preorder-traversal
0776-n-ary-tree-postorder-traversal

Breadth-First Search

0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0226-invert-binary-tree
0404-sum-of-left-leaves
0463-island-perimeter
0530-minimum-absolute-difference-in-bst
0617-merge-two-binary-trees
0637-average-of-levels-in-binary-tree
0653-two-sum-iv-input-is-a-bst
0774-maximum-depth-of-n-ary-tree

Binary Tree

0094-binary-tree-inorder-traversal
0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0108-convert-sorted-array-to-binary-search-tree
0110-balanced-binary-tree
0111-minimum-depth-of-binary-tree
0112-path-sum
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0226-invert-binary-tree
0257-binary-tree-paths
0404-sum-of-left-leaves
0501-find-mode-in-binary-search-tree
0530-minimum-absolute-difference-in-bst
0563-binary-tree-tilt
0572-subtree-of-another-tree
0617-merge-two-binary-trees
0637-average-of-levels-in-binary-tree
0653-two-sum-iv-input-is-a-bst
0671-second-minimum-node-in-a-binary-tree

Counting Sort

0169-majority-element
0383-ransom-note
0387-first-unique-character-in-a-string
0561-array-partition
0594-longest-harmonious-subsequence
0837-most-common-word
2148-minimum-number-of-moves-to-seat-everyone

Binary Search Tree

0108-convert-sorted-array-to-binary-search-tree
0501-find-mode-in-binary-search-tree
0530-minimum-absolute-difference-in-bst
0653-two-sum-iv-input-is-a-bst

Design

0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0303-range-sum-query-immutable

Queue

0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0387-first-unique-character-in-a-string

Interactive

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

Prefix Sum

0303-range-sum-query-immutable
0724-find-pivot-index

Brainteaser

0292-nim-game

Game Theory

0292-nim-game

Heap (Priority Queue)

0506-relative-ranks

Monotonic Stack

0496-next-greater-element-i

Hash Function

0572-subtree-of-another-tree

Geometry

0830-largest-triangle-area