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

LeetCode Topics

Array

0015-3sum
0016-3sum-closest
0018-4sum
0031-next-permutation
0033-search-in-rotated-sorted-array
0039-combination-sum
0040-combination-sum-ii
0042-trapping-rain-water
0047-permutations-ii
0048-rotate-image
0051-n-queens
0054-spiral-matrix
0059-spiral-matrix-ii
0064-minimum-path-sum
0066-plus-one
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0075-sort-colors
0078-subsets
0081-search-in-rotated-sorted-array-ii
0088-merge-sorted-array
0118-pascals-triangle
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0189-rotate-array
0198-house-robber
0209-minimum-size-subarray-sum
0218-the-skyline-problem
0268-missing-number
0287-find-the-duplicate-number
0300-longest-increasing-subsequence
0322-coin-change
0349-intersection-of-two-arrays
0378-kth-smallest-element-in-a-sorted-matrix
0456-132-pattern
0724-find-pivot-index
0729-my-calendar-i
0747-min-cost-climbing-stairs
0859-design-circular-deque
0860-design-circular-queue
0882-peak-index-in-a-mountain-array
0940-fruit-into-baskets
1056-capacity-to-ship-packages-within-d-days
1397-search-suggestions-system
1408-find-the-smallest-divisor-given-a-threshold
1421-find-numbers-with-even-number-of-digits
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1628-count-submatrices-with-all-ones
1633-minimum-number-of-increments-on-subarrays-to-form-a-target-array
1961-maximum-ice-cream-bars
2015-determine-whether-matrix-can-be-obtained-by-rotation
2048-build-array-from-permutation
2144-maximum-difference-between-increasing-elements
2215-finding-3-digit-even-numbers
2229-maximum-fruits-harvested-after-at-most-k-steps
2237-longest-palindrome-by-concatenating-two-letter-words
2320-find-all-k-distant-indices-in-an-array
2503-longest-subarray-with-maximum-bitwise-and
3143-longest-unequal-adjacent-groups-subsequence-i
3194-find-words-containing-character
3213-count-subarrays-where-max-element-appears-at-least-k-times
3241-divide-array-into-arrays-with-max-difference
3278-find-the-number-of-ways-to-place-people-i
3639-zero-array-transformation-i
3747-maximum-difference-between-adjacent-elements-in-a-circular-array

Dynamic Programming

0005-longest-palindromic-substring
0042-trapping-rain-water
0064-minimum-path-sum
0070-climbing-stairs
0072-edit-distance
0118-pascals-triangle
0198-house-robber
0233-number-of-digit-one
0264-ugly-number-ii
0300-longest-increasing-subsequence
0322-coin-change
0516-longest-palindromic-subsequence
0747-min-cost-climbing-stairs
0868-push-dominoes
1250-longest-common-subsequence
1628-count-submatrices-with-all-ones
1633-minimum-number-of-increments-on-subarrays-to-form-a-target-array
3143-longest-unequal-adjacent-groups-subsequence-i
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-ii

Stack

0042-trapping-rain-water
0224-basic-calculator
0316-remove-duplicate-letters
0456-132-pattern
1159-smallest-subsequence-of-distinct-characters
1628-count-submatrices-with-all-ones
1633-minimum-number-of-increments-on-subarrays-to-form-a-target-array

Greedy

0316-remove-duplicate-letters
0409-longest-palindrome
1159-smallest-subsequence-of-distinct-characters
1529-max-difference-you-can-get-from-changing-an-integer
1633-minimum-number-of-increments-on-subarrays-to-form-a-target-array
1961-maximum-ice-cream-bars
2149-remove-colored-pieces-if-both-neighbors-are-the-same-color
2237-longest-palindrome-by-concatenating-two-letter-words
2704-maximum-difference-by-remapping-a-digit
3143-longest-unequal-adjacent-groups-subsequence-i
3241-divide-array-into-arrays-with-max-difference

Monotonic Stack

0042-trapping-rain-water
0316-remove-duplicate-letters
0456-132-pattern
1159-smallest-subsequence-of-distinct-characters
1628-count-submatrices-with-all-ones
1633-minimum-number-of-increments-on-subarrays-to-form-a-target-array

Matrix

0048-rotate-image
0054-spiral-matrix
0059-spiral-matrix-ii
0064-minimum-path-sum
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0378-kth-smallest-element-in-a-sorted-matrix
1628-count-submatrices-with-all-ones
2015-determine-whether-matrix-can-be-obtained-by-rotation

Binary Search

0033-search-in-rotated-sorted-array
0074-search-a-2d-matrix
0081-search-in-rotated-sorted-array-ii
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0167-two-sum-ii-input-array-is-sorted
0209-minimum-size-subarray-sum
0268-missing-number
0287-find-the-duplicate-number
0300-longest-increasing-subsequence
0349-intersection-of-two-arrays
0378-kth-smallest-element-in-a-sorted-matrix
0456-132-pattern
0729-my-calendar-i
0882-peak-index-in-a-mountain-array
1056-capacity-to-ship-packages-within-d-days
1358-find-positive-integer-solution-for-a-given-equation
1397-search-suggestions-system
1408-find-the-smallest-divisor-given-a-threshold
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
2229-maximum-fruits-harvested-after-at-most-k-steps

Ordered Set

0218-the-skyline-problem
0456-132-pattern
0729-my-calendar-i

Hash Table

0003-longest-substring-without-repeating-characters
0017-letter-combinations-of-a-phone-number
0073-set-matrix-zeroes
0264-ugly-number-ii
0268-missing-number
0349-intersection-of-two-arrays
0409-longest-palindrome
0940-fruit-into-baskets
1915-check-if-one-string-swap-can-make-strings-equal
2215-finding-3-digit-even-numbers
2237-longest-palindrome-by-concatenating-two-letter-words
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-ii
3753-maximum-difference-between-even-and-odd-frequency-i

Math

0043-multiply-strings
0048-rotate-image
0050-powx-n
0060-permutation-sequence
0066-plus-one
0070-climbing-stairs
0089-gray-code
0189-rotate-array
0224-basic-calculator
0231-power-of-two
0233-number-of-digit-one
0264-ugly-number-ii
0268-missing-number
0282-expression-add-operators
1358-find-positive-integer-solution-for-a-given-equation
1421-find-numbers-with-even-number-of-digits
1529-max-difference-you-can-get-from-changing-an-integer
2149-remove-colored-pieces-if-both-neighbors-are-the-same-color
2202-sum-of-k-mirror-numbers
2704-maximum-difference-by-remapping-a-digit
3172-divisible-and-non-divisible-sums-difference
3278-find-the-number-of-ways-to-place-people-i
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-ii

String

0003-longest-substring-without-repeating-characters
0005-longest-palindromic-substring
0006-zigzag-conversion
0017-letter-combinations-of-a-phone-number
0043-multiply-strings
0058-length-of-last-word
0072-edit-distance
0224-basic-calculator
0282-expression-add-operators
0316-remove-duplicate-letters
0409-longest-palindrome
0516-longest-palindromic-subsequence
0868-push-dominoes
1058-lexicographically-smallest-equivalent-string
1159-smallest-subsequence-of-distinct-characters
1250-longest-common-subsequence
1397-search-suggestions-system
1915-check-if-one-string-swap-can-make-strings-equal
2149-remove-colored-pieces-if-both-neighbors-are-the-same-color
2237-longest-palindrome-by-concatenating-two-letter-words
3143-longest-unequal-adjacent-groups-subsequence-i
3194-find-words-containing-character
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-ii
3753-maximum-difference-between-even-and-odd-frequency-i

Counting

1915-check-if-one-string-swap-can-make-strings-equal
2237-longest-palindrome-by-concatenating-two-letter-words
3629-total-characters-in-string-after-transformations-i
3630-total-characters-in-string-after-transformations-ii
3753-maximum-difference-between-even-and-odd-frequency-i

Sorting

0015-3sum
0016-3sum-closest
0018-4sum
0047-permutations-ii
0075-sort-colors
0088-merge-sorted-array
0268-missing-number
0349-intersection-of-two-arrays
0378-kth-smallest-element-in-a-sorted-matrix
1397-search-suggestions-system
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1961-maximum-ice-cream-bars
2215-finding-3-digit-even-numbers
3241-divide-array-into-arrays-with-max-difference
3278-find-the-number-of-ways-to-place-people-i

Enumeration

2202-sum-of-k-mirror-numbers
2215-finding-3-digit-even-numbers
3278-find-the-number-of-ways-to-place-people-i

Linked List

0021-merge-two-sorted-lists
0859-design-circular-deque
0860-design-circular-queue

Design

0729-my-calendar-i
0859-design-circular-deque
0860-design-circular-queue

Queue

0859-design-circular-deque
0860-design-circular-queue

Sliding Window

0003-longest-substring-without-repeating-characters
0209-minimum-size-subarray-sum
0940-fruit-into-baskets
2229-maximum-fruits-harvested-after-at-most-k-steps
3213-count-subarrays-where-max-element-appears-at-least-k-times

Simulation

0043-multiply-strings
0054-spiral-matrix
0059-spiral-matrix-ii
2048-build-array-from-permutation

Two Pointers

0005-longest-palindromic-substring
0015-3sum
0016-3sum-closest
0018-4sum
0031-next-permutation
0042-trapping-rain-water
0075-sort-colors
0088-merge-sorted-array
0167-two-sum-ii-input-array-is-sorted
0189-rotate-array
0287-find-the-duplicate-number
0349-intersection-of-two-arrays
0868-push-dominoes
1358-find-positive-integer-solution-for-a-given-equation
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
2320-find-all-k-distant-indices-in-an-array

Backtracking

0017-letter-combinations-of-a-phone-number
0039-combination-sum
0040-combination-sum-ii
0047-permutations-ii
0051-n-queens
0077-combinations
0078-subsets
0089-gray-code
0282-expression-add-operators

Game Theory

2149-remove-colored-pieces-if-both-neighbors-are-the-same-color

Bit Manipulation

0078-subsets
0089-gray-code
0201-bitwise-and-of-numbers-range
0231-power-of-two
0268-missing-number
0287-find-the-duplicate-number
2503-longest-subarray-with-maximum-bitwise-and

Brainteaser

2503-longest-subarray-with-maximum-bitwise-and

Recursion

0021-merge-two-sorted-lists
0050-powx-n
0060-permutation-sequence
0224-basic-calculator
0231-power-of-two
0233-number-of-digit-one

Heap (Priority Queue)

0218-the-skyline-problem
0264-ugly-number-ii
0378-kth-smallest-element-in-a-sorted-matrix
1397-search-suggestions-system

Segment Tree

0218-the-skyline-problem
0729-my-calendar-i

Interactive

1358-find-positive-integer-solution-for-a-given-equation

Trie

1397-search-suggestions-system

Prefix Sum

0209-minimum-size-subarray-sum
0724-find-pivot-index
2229-maximum-fruits-harvested-after-at-most-k-steps
3639-zero-array-transformation-i

Counting Sort

1961-maximum-ice-cream-bars

Memoization

0070-climbing-stairs

Union Find

1058-lexicographically-smallest-equivalent-string

Divide and Conquer

0218-the-skyline-problem

Binary Indexed Tree

0218-the-skyline-problem

Line Sweep

0218-the-skyline-problem

Database

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
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
0607-sales-person
0608-tree-node
0610-triangle-judgement
0620-not-boring-movies
1153-product-sales-analysis-i
1179-game-play-analysis-i
1182-game-play-analysis-iv
1258-article-views-i
1390-average-selling-price
1415-students-and-examinations
1509-replace-employee-id-with-the-unique-identifier
1724-customer-who-visited-but-did-not-make-any-transactions
1801-average-time-of-process-per-machine
1827-invalid-tweets
1877-find-followers-count
1908-recyclable-and-low-fat-products
2087-confirmation-rate

Breadth-First Search

0322-coin-change

Geometry

3278-find-the-number-of-ways-to-place-people-i