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

LeetCode Topics

Array

0001-two-sum
0011-container-with-most-water
0014-longest-common-prefix
0015-3sum
0026-remove-duplicates-from-sorted-array
0027-remove-element
0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0041-first-missing-positive
0042-trapping-rain-water
0049-group-anagrams
0053-maximum-subarray
0054-spiral-matrix
0055-jump-game
0056-merge-intervals
0057-insert-interval
0059-spiral-matrix-ii
0066-plus-one
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0078-subsets
0080-remove-duplicates-from-sorted-array-ii
0081-search-in-rotated-sorted-array-ii
0085-maximal-rectangle
0118-pascals-triangle
0119-pascals-triangle-ii
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0136-single-number
0137-single-number-ii
0149-max-points-on-a-line
0153-find-minimum-in-rotated-sorted-array
0154-find-minimum-in-rotated-sorted-array-ii
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0169-majority-element
0204-count-primes
0209-minimum-size-subarray-sum
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0219-contains-duplicate-ii
0240-search-a-2d-matrix-ii
0268-missing-number
0274-h-index
0275-h-index-ii
0283-move-zeroes
0287-find-the-duplicate-number
0289-game-of-life
0349-intersection-of-two-arrays
0414-third-maximum-number
0448-find-all-numbers-disappeared-in-an-array
0493-reverse-pairs
0566-reshape-the-matrix
0628-maximum-product-of-three-numbers
0643-maximum-average-subarray-i
0658-find-k-closest-elements
0792-binary-search
0812-largest-triangle-area
0861-flipping-an-image
0882-peak-index-in-a-mountain-array
0883-projection-area-of-3d-shapes
0890-lemonade-change
0891-score-after-flipping-matrix
0898-transpose-matrix
0941-sort-array-by-parity
0944-delete-columns-to-make-sorted
0961-n-repeated-element-in-size-2n-array
1056-capacity-to-ship-packages-within-d-days
1239-maximum-length-of-a-concatenated-string-with-unique-characters
1253-sort-the-matrix-diagonally
1266-minimum-time-visiting-all-points
1292-maximum-side-length-of-a-square-with-sum-less-than-or-equal-to-threshold
1295-find-numbers-with-even-number-of-digits
1378-cells-with-odd-values-in-a-matrix
1390-four-divisors
1408-find-the-smallest-divisor-given-a-threshold
1458-max-dot-product-of-two-subsequences
1470-shuffle-the-array
1476-count-negative-numbers-in-a-sorted-matrix
1502-can-make-arithmetic-progression-from-sequence
1510-find-lucky-integer-in-an-array
1603-running-sum-of-1d-array
1656-count-good-triplets
1677-matrix-diagonal-sum
1798-max-number-of-k-sum-pairs
1895-largest-magic-square
1951-find-the-winner-of-the-circular-game
1975-maximum-matrix-sum
2122-count-special-quadruplets
2144-maximum-difference-between-increasing-elements
2316-count-hills-and-valleys-in-an-array
2386-min-max-game
2392-successful-pairs-of-spells-and-potions
2433-find-the-original-array-of-prefix-xor
2455-average-value-of-even-numbers-that-are-divisible-by-three
2943-maximize-area-of-square-hole-in-grid
2975-maximum-square-area-by-removing-fences-from-a-field
3047-find-the-largest-area-of-square-inside-two-rectangles
3314-construct-the-minimum-bitwise-array-i
3315-construct-the-minimum-bitwise-array-ii
3321-type-of-triangle
3453-separate-squares-i
3454-separate-squares-ii
3501-delete-nodes-from-linked-list-present-in-array
3581-the-two-sneaky-numbers-of-digitville
3591-check-if-any-element-has-prime-frequency
3612-adjacent-increasing-subarrays-detection-i
3747-maximum-difference-between-adjacent-elements-in-a-circular-array
3797-design-spreadsheet

Hash Table

0001-two-sum
0012-integer-to-roman
0013-roman-to-integer
0041-first-missing-positive
0049-group-anagrams
0073-set-matrix-zeroes
0138-copy-list-with-random-pointer
0141-linked-list-cycle
0142-linked-list-cycle-ii
0146-lru-cache
0149-max-points-on-a-line
0160-intersection-of-two-linked-lists
0169-majority-element
0202-happy-number
0205-isomorphic-strings
0217-contains-duplicate
0219-contains-duplicate-ii
0242-valid-anagram
0268-missing-number
0349-intersection-of-two-arrays
0448-find-all-numbers-disappeared-in-an-array
0460-lfu-cache
0865-smallest-subtree-with-all-the-deepest-nodes
0889-buddy-strings
0961-n-repeated-element-in-size-2n-array
1015-smallest-integer-divisible-by-k
1123-lowest-common-ancestor-of-deepest-leaves
1264-maximum-number-of-words-you-can-type
1510-find-lucky-integer-in-an-array
1798-max-number-of-k-sum-pairs
2122-count-special-quadruplets
2975-maximum-square-area-by-removing-fences-from-a-field
3501-delete-nodes-from-linked-list-present-in-array
3581-the-two-sneaky-numbers-of-digitville
3591-check-if-any-element-has-prime-frequency
3797-design-spreadsheet

Two Pointers

0005-longest-palindromic-substring
0011-container-with-most-water
0015-3sum
0019-remove-nth-node-from-end-of-list
0026-remove-duplicates-from-sorted-array
0027-remove-element
0042-trapping-rain-water
0061-rotate-list
0080-remove-duplicates-from-sorted-array-ii
0082-remove-duplicates-from-sorted-list-ii
0086-partition-list
0141-linked-list-cycle
0142-linked-list-cycle-ii
0143-reorder-list
0148-sort-list
0151-reverse-words-in-a-string
0160-intersection-of-two-linked-lists
0167-two-sum-ii-input-array-is-sorted
0202-happy-number
0234-palindrome-linked-list
0283-move-zeroes
0287-find-the-duplicate-number
0344-reverse-string
0345-reverse-vowels-of-a-string
0349-intersection-of-two-arrays
0392-is-subsequence
0443-string-compression
0528-swapping-nodes-in-a-linked-list
0541-reverse-string-ii
0658-find-k-closest-elements
0861-flipping-an-image
0908-middle-of-the-linked-list
0941-sort-array-by-parity
1798-max-number-of-k-sum-pairs
2216-delete-the-middle-node-of-a-linked-list
2392-successful-pairs-of-spells-and-potions

Dynamic Programming

0005-longest-palindromic-substring
0022-generate-parentheses
0042-trapping-rain-water
0053-maximum-subarray
0055-jump-game
0070-climbing-stairs
0085-maximal-rectangle
0118-pascals-triangle
0119-pascals-triangle-ii
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0233-number-of-digit-one
0338-counting-bits
0392-is-subsequence
0712-minimum-ascii-delete-sum-for-two-strings
1013-fibonacci-number
1086-divisor-game
1236-n-th-tribonacci-number
1411-number-of-ways-to-paint-n-3-grid
1458-max-dot-product-of-two-subsequences
1866-number-of-ways-to-rearrange-sticks-with-k-sticks-visible

Divide and Conquer

0023-merge-k-sorted-lists
0053-maximum-subarray
0148-sort-list
0169-majority-element
0191-number-of-1-bits
0215-kth-largest-element-in-an-array
0240-search-a-2d-matrix-ii
0493-reverse-pairs

Binary Search

0033-search-in-rotated-sorted-array
0034-find-first-and-last-position-of-element-in-sorted-array
0069-sqrtx
0074-search-a-2d-matrix
0081-search-in-rotated-sorted-array-ii
0153-find-minimum-in-rotated-sorted-array
0154-find-minimum-in-rotated-sorted-array-ii
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0209-minimum-size-subarray-sum
0240-search-a-2d-matrix-ii
0268-missing-number
0275-h-index-ii
0278-first-bad-version
0287-find-the-duplicate-number
0349-intersection-of-two-arrays
0367-valid-perfect-square
0493-reverse-pairs
0658-find-k-closest-elements
0792-binary-search
0882-peak-index-in-a-mountain-array
1056-capacity-to-ship-packages-within-d-days
1292-maximum-side-length-of-a-square-with-sum-less-than-or-equal-to-threshold
1408-find-the-smallest-divisor-given-a-threshold
1476-count-negative-numbers-in-a-sorted-matrix
2392-successful-pairs-of-spells-and-potions
3453-separate-squares-i
3454-separate-squares-ii

Sliding Window

0209-minimum-size-subarray-sum
0219-contains-duplicate-ii
0643-maximum-average-subarray-i
0658-find-k-closest-elements

Prefix Sum

0209-minimum-size-subarray-sum
1292-maximum-side-length-of-a-square-with-sum-less-than-or-equal-to-threshold
1603-running-sum-of-1d-array
1895-largest-magic-square
2485-find-the-pivot-integer

Math

0002-add-two-numbers
0007-reverse-integer
0009-palindrome-number
0012-integer-to-roman
0013-roman-to-integer
0029-divide-two-integers
0043-multiply-strings
0050-powx-n
0060-permutation-sequence
0066-plus-one
0069-sqrtx
0070-climbing-stairs
0089-gray-code
0149-max-points-on-a-line
0168-excel-sheet-column-title
0172-factorial-trailing-zeroes
0202-happy-number
0204-count-primes
0223-rectangle-area
0231-power-of-two
0233-number-of-digit-one
0258-add-digits
0263-ugly-number
0268-missing-number
0292-nim-game
0326-power-of-three
0342-power-of-four
0367-valid-perfect-square
0371-sum-of-two-integers
0412-fizz-buzz
0628-maximum-product-of-three-numbers
0728-self-dividing-numbers
0812-largest-triangle-area
0858-mirror-reflection
0883-projection-area-of-3d-shapes
1013-fibonacci-number
1015-smallest-integer-divisible-by-k
1086-divisor-game
1236-n-th-tribonacci-number
1266-minimum-time-visiting-all-points
1295-find-numbers-with-even-number-of-digits
1378-cells-with-odd-values-in-a-matrix
1390-four-divisors
1440-convert-integer-to-the-sum-of-two-no-zero-integers
1444-number-of-steps-to-reduce-a-number-to-zero
1448-maximum-69-number
1523-count-odd-numbers-in-an-interval-range
1610-xor-operation-in-an-array
1688-count-of-matches-in-tournament
1806-count-of-matches-in-tournament
1866-number-of-ways-to-rearrange-sticks-with-k-sticks-visible
1951-find-the-winner-of-the-circular-game
2083-three-divisors
2180-count-integers-with-even-digit-sum
2238-a-number-after-a-double-reversal
2455-average-value-of-even-numbers-that-are-divisible-by-three
2485-find-the-pivot-integer
2520-count-the-digits-that-divide-a-number
2523-closest-prime-numbers-in-range
2556-convert-the-temperature
2752-sum-multiples
2894-divisible-and-non-divisible-sums-difference
3047-find-the-largest-area-of-square-inside-two-rectangles
3172-divisible-and-non-divisible-sums-difference
3321-type-of-triangle
3511-find-the-winning-player-in-coin-game
3581-the-two-sneaky-numbers-of-digitville
3591-check-if-any-element-has-prime-frequency
3622-check-divisibility-by-digit-sum-and-product

Recursion

0002-add-two-numbers
0021-merge-two-sorted-lists
0024-swap-nodes-in-pairs
0050-powx-n
0060-permutation-sequence
0143-reorder-list
0203-remove-linked-list-elements
0206-reverse-linked-list
0231-power-of-two
0233-number-of-digit-one
0234-palindrome-linked-list
0326-power-of-three
0342-power-of-four
1013-fibonacci-number
1951-find-the-winner-of-the-circular-game

Memoization

0070-climbing-stairs
1013-fibonacci-number
1236-n-th-tribonacci-number

Bit Manipulation

0029-divide-two-integers
0078-subsets
0089-gray-code
0136-single-number
0137-single-number-ii
0191-number-of-1-bits
0231-power-of-two
0268-missing-number
0287-find-the-duplicate-number
0338-counting-bits
0342-power-of-four
0371-sum-of-two-integers
0861-flipping-an-image
0891-score-after-flipping-matrix
1239-maximum-length-of-a-concatenated-string-with-unique-characters
1444-number-of-steps-to-reduce-a-number-to-zero
1610-xor-operation-in-an-array
2433-find-the-original-array-of-prefix-xor
3314-construct-the-minimum-bitwise-array-i
3315-construct-the-minimum-bitwise-array-ii

Matrix

0054-spiral-matrix
0059-spiral-matrix-ii
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0085-maximal-rectangle
0240-search-a-2d-matrix-ii
0289-game-of-life
0566-reshape-the-matrix
0861-flipping-an-image
0883-projection-area-of-3d-shapes
0891-score-after-flipping-matrix
0898-transpose-matrix
1253-sort-the-matrix-diagonally
1292-maximum-side-length-of-a-square-with-sum-less-than-or-equal-to-threshold
1476-count-negative-numbers-in-a-sorted-matrix
1677-matrix-diagonal-sum
1895-largest-magic-square
1975-maximum-matrix-sum
3797-design-spreadsheet

Simulation

0043-multiply-strings
0054-spiral-matrix
0059-spiral-matrix-ii
0258-add-digits
0289-game-of-life
0412-fizz-buzz
0566-reshape-the-matrix
0861-flipping-an-image
0898-transpose-matrix
1378-cells-with-odd-values-in-a-matrix
1688-count-of-matches-in-tournament
1806-count-of-matches-in-tournament
1951-find-the-winner-of-the-circular-game
2180-count-integers-with-even-digit-sum
2386-min-max-game
3174-clear-digits
3511-find-the-winning-player-in-coin-game

Sorting

0015-3sum
0049-group-anagrams
0056-merge-intervals
0148-sort-list
0169-majority-element
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0242-valid-anagram
0268-missing-number
0274-h-index
0349-intersection-of-two-arrays
0414-third-maximum-number
0628-maximum-product-of-three-numbers
0658-find-k-closest-elements
0941-sort-array-by-parity
1253-sort-the-matrix-diagonally
1502-can-make-arithmetic-progression-from-sequence
1798-max-number-of-k-sum-pairs
2392-successful-pairs-of-spells-and-potions
2943-maximize-area-of-square-hole-in-grid
3321-type-of-triangle

String

0005-longest-palindromic-substring
0006-zigzag-conversion
0012-integer-to-roman
0013-roman-to-integer
0014-longest-common-prefix
0020-valid-parentheses
0022-generate-parentheses
0038-count-and-say
0043-multiply-strings
0049-group-anagrams
0058-length-of-last-word
0151-reverse-words-in-a-string
0168-excel-sheet-column-title
0205-isomorphic-strings
0242-valid-anagram
0344-reverse-string
0345-reverse-vowels-of-a-string
0392-is-subsequence
0412-fizz-buzz
0443-string-compression
0541-reverse-string-ii
0649-dota2-senate
0712-minimum-ascii-delete-sum-for-two-strings
0889-buddy-strings
0944-delete-columns-to-make-sorted
1108-defanging-an-ip-address
1239-maximum-length-of-a-concatenated-string-with-unique-characters
1264-maximum-number-of-words-you-can-type
3174-clear-digits
3797-design-spreadsheet

Greedy

0011-container-with-most-water
0055-jump-game
0122-best-time-to-buy-and-sell-stock-ii
0649-dota2-senate
0890-lemonade-change
0891-score-after-flipping-matrix
1448-maximum-69-number
1975-maximum-matrix-sum

Brainteaser

0292-nim-game
1086-divisor-game

Game Theory

0292-nim-game
1086-divisor-game
3511-find-the-winning-player-in-coin-game

Linked List

0002-add-two-numbers
0019-remove-nth-node-from-end-of-list
0021-merge-two-sorted-lists
0023-merge-k-sorted-lists
0024-swap-nodes-in-pairs
0061-rotate-list
0082-remove-duplicates-from-sorted-list-ii
0083-remove-duplicates-from-sorted-list
0086-partition-list
0092-reverse-linked-list-ii
0138-copy-list-with-random-pointer
0141-linked-list-cycle
0142-linked-list-cycle-ii
0143-reorder-list
0146-lru-cache
0148-sort-list
0160-intersection-of-two-linked-lists
0203-remove-linked-list-elements
0206-reverse-linked-list
0234-palindrome-linked-list
0237-delete-node-in-a-linked-list
0328-odd-even-linked-list
0460-lfu-cache
0528-swapping-nodes-in-a-linked-list
0725-split-linked-list-in-parts
0766-flatten-a-multilevel-doubly-linked-list
0908-middle-of-the-linked-list
2182-find-the-minimum-and-maximum-number-of-nodes-between-critical-points
2216-delete-the-middle-node-of-a-linked-list
3501-delete-nodes-from-linked-list-present-in-array

Enumeration

0204-count-primes
1656-count-good-triplets
2083-three-divisors
2122-count-special-quadruplets
2975-maximum-square-area-by-removing-fences-from-a-field

Number Theory

0204-count-primes
0258-add-digits
0858-mirror-reflection
2083-three-divisors
2523-closest-prime-numbers-in-range
3591-check-if-any-element-has-prime-frequency

Stack

0020-valid-parentheses
0042-trapping-rain-water
0085-maximal-rectangle
0094-binary-tree-inorder-traversal
0143-reorder-list
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0234-palindrome-linked-list
3174-clear-digits

Design

0146-lru-cache
0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0460-lfu-cache
0703-kth-largest-element-in-a-stream
0969-number-of-recent-calls
3797-design-spreadsheet

Queue

0225-implement-stack-using-queues
0232-implement-queue-using-stacks
0649-dota2-senate
0969-number-of-recent-calls
1951-find-the-winner-of-the-circular-game

Data Stream

0703-kth-largest-element-in-a-stream
0969-number-of-recent-calls

Counting

0169-majority-element
1510-find-lucky-integer-in-an-array
3591-check-if-any-element-has-prime-frequency

Tree

0094-binary-tree-inorder-traversal
0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0111-minimum-depth-of-binary-tree
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0226-invert-binary-tree
0235-lowest-common-ancestor-of-a-binary-search-tree
0515-find-largest-value-in-each-tree-row
0703-kth-largest-element-in-a-stream
0865-smallest-subtree-with-all-the-deepest-nodes
1123-lowest-common-ancestor-of-deepest-leaves
1161-maximum-level-sum-of-a-binary-tree
1339-maximum-product-of-splitted-binary-tree

Depth-First Search

0094-binary-tree-inorder-traversal
0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0111-minimum-depth-of-binary-tree
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0226-invert-binary-tree
0235-lowest-common-ancestor-of-a-binary-search-tree
0515-find-largest-value-in-each-tree-row
0766-flatten-a-multilevel-doubly-linked-list
0865-smallest-subtree-with-all-the-deepest-nodes
1123-lowest-common-ancestor-of-deepest-leaves
1161-maximum-level-sum-of-a-binary-tree
1339-maximum-product-of-splitted-binary-tree

Breadth-First Search

0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0111-minimum-depth-of-binary-tree
0226-invert-binary-tree
0515-find-largest-value-in-each-tree-row
0865-smallest-subtree-with-all-the-deepest-nodes
1123-lowest-common-ancestor-of-deepest-leaves
1161-maximum-level-sum-of-a-binary-tree

Binary Tree

0094-binary-tree-inorder-traversal
0100-same-tree
0101-symmetric-tree
0104-maximum-depth-of-binary-tree
0111-minimum-depth-of-binary-tree
0144-binary-tree-preorder-traversal
0145-binary-tree-postorder-traversal
0226-invert-binary-tree
0235-lowest-common-ancestor-of-a-binary-search-tree
0515-find-largest-value-in-each-tree-row
0703-kth-largest-element-in-a-stream
0865-smallest-subtree-with-all-the-deepest-nodes
1123-lowest-common-ancestor-of-deepest-leaves
1161-maximum-level-sum-of-a-binary-tree
1339-maximum-product-of-splitted-binary-tree

Binary Search Tree

0235-lowest-common-ancestor-of-a-binary-search-tree
0703-kth-largest-element-in-a-stream

Heap (Priority Queue)

0023-merge-k-sorted-lists
0215-kth-largest-element-in-an-array
0658-find-k-closest-elements
0703-kth-largest-element-in-a-stream

Backtracking

0022-generate-parentheses
0077-combinations
0078-subsets
0089-gray-code
1239-maximum-length-of-a-concatenated-string-with-unique-characters

Binary Indexed Tree

0493-reverse-pairs

Segment Tree

0493-reverse-pairs
3454-separate-squares-ii

Merge Sort

0023-merge-k-sorted-lists
0148-sort-list
0493-reverse-pairs

Ordered Set

0493-reverse-pairs

Quickselect

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

Database

0175-combine-two-tables
0176-second-highest-salary
0178-rank-scores
0180-consecutive-numbers
0181-employees-earning-more-than-their-managers
0185-department-top-three-salaries
0196-delete-duplicate-emails
0197-rising-temperature
0262-trips-and-users
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-with-at-least-5-students
0602-friend-requests-ii-who-has-the-most-friends
0608-tree-node
0610-triangle-judgement
0619-biggest-single-number
0620-not-boring-movies
0626-exchange-seats
1045-customers-who-bought-all-products
1135-customers-who-bought-all-products
1153-product-sales-analysis-i
1155-product-sales-analysis-iii
1161-project-employees-i
1182-game-play-analysis-iv
1245-user-activity-for-the-past-30-days-i
1258-article-views-i
1278-product-price-at-a-given-date
1280-students-and-examinations
1292-immediate-food-delivery-ii
1317-monthly-transactions-i
1327-last-person-to-fit-in-the-bus
1338-queries-quality-and-percentage
1341-movie-rating
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
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
1773-percentage-of-users-attended-a-contest
1801-average-time-of-process-per-machine
1811-fix-names-in-a-table
1827-invalid-tweets
1877-find-followers-count
1882-the-number-of-employees-which-report-to-each-employee
1908-recyclable-and-low-fat-products
1942-primary-department-for-each-employee
2057-count-salary-categories
2087-confirmation-rate
2127-employees-whose-manager-left-the-company
2495-number-of-unique-subjects-taught-by-each-teacher

Doubly-Linked List

0146-lru-cache
0460-lfu-cache
0766-flatten-a-multilevel-doubly-linked-list

Trie

0014-longest-common-prefix

Combinatorics

1866-number-of-ways-to-rearrange-sticks-with-k-sticks-visible

Geometry

0149-max-points-on-a-line
0223-rectangle-area
0812-largest-triangle-area
0858-mirror-reflection
0883-projection-area-of-3d-shapes
1266-minimum-time-visiting-all-points
3047-find-the-largest-area-of-square-inside-two-rectangles

Interactive

0278-first-bad-version

Counting Sort

0274-h-index

Monotonic Stack

0042-trapping-rain-water
0085-maximal-rectangle

Line Sweep

3454-separate-squares-ii