DSA-Leetcode

Collection of LeetCode questions!

LeetCode Topics

Math

0007-reverse-integer
0012-integer-to-roman
0013-roman-to-integer
0048-rotate-image
0066-plus-one
0171-excel-sheet-column-number
0202-happy-number
0231-power-of-two
0268-missing-number
0292-nim-game
0326-power-of-three
0342-power-of-four
0343-integer-break
0371-sum-of-two-integers
0628-maximum-product-of-three-numbers
0826-soup-servings
0867-new-21-game
0900-reordered-power-of-2
1013-fibonacci-number
1411-convert-binary-number-in-a-linked-list-to-integer
1426-find-n-unique-integers-sum-up-to-zero
1440-convert-integer-to-the-sum-of-two-no-zero-integers
1529-max-difference-you-can-get-from-changing-an-integer
2432-number-of-zero-filled-subarrays
2481-strictly-palindromic-number
2704-maximum-difference-by-remapping-a-digit
3172-divisible-and-non-divisible-sums-difference
3278-find-the-number-of-ways-to-place-people-i
3516-find-closest-person
3600-find-the-k-th-character-in-string-game-i
3754-maximum-manhattan-distance-after-k-changes

Dynamic Programming

0022-generate-parentheses
0042-trapping-rain-water
0055-jump-game
0118-pascals-triangle
0119-pascals-triangle-ii
0121-best-time-to-buy-and-sell-stock
0152-maximum-product-subarray
0338-counting-bits
0343-integer-break
0392-is-subsequence
0410-split-array-largest-sum
0826-soup-servings
0867-new-21-game
0868-push-dominoes
0934-bitwise-ors-of-subarrays
1013-fibonacci-number
1402-count-square-submatrices-with-all-ones
1586-longest-subarray-of-1s-after-deleting-one-element
1628-count-submatrices-with-all-ones
3143-longest-unequal-adjacent-groups-subsequence-i
3490-find-the-maximum-length-of-valid-subsequence-i
3491-find-the-maximum-length-of-valid-subsequence-ii

Recursion

0021-merge-two-sorted-lists
0231-power-of-two
0326-power-of-three
0342-power-of-four
1013-fibonacci-number
3600-find-the-k-th-character-in-string-game-i

Memoization

1013-fibonacci-number

Array

0001-two-sum
0004-median-of-two-sorted-arrays
0011-container-with-most-water
0015-3sum
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
0041-first-missing-positive
0042-trapping-rain-water
0048-rotate-image
0049-group-anagrams
0054-spiral-matrix
0055-jump-game
0056-merge-intervals
0066-plus-one
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0075-sort-colors
0080-remove-duplicates-from-sorted-array-ii
0081-search-in-rotated-sorted-array-ii
0088-merge-sorted-array
0118-pascals-triangle
0119-pascals-triangle-ii
0121-best-time-to-buy-and-sell-stock
0128-longest-consecutive-sequence
0135-candy
0136-single-number
0152-maximum-product-subarray
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0164-maximum-gap
0169-majority-element
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0220-contains-duplicate-iii
0229-majority-element-ii
0238-product-of-array-except-self
0268-missing-number
0283-move-zeroes
0287-find-the-duplicate-number
0347-top-k-frequent-elements
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0378-kth-smallest-element-in-a-sorted-matrix
0410-split-array-largest-sum
0414-third-maximum-number
0452-minimum-number-of-arrows-to-burst-balloons
0455-assign-cookies
0485-max-consecutive-ones
0506-relative-ranks
0540-single-element-in-a-sorted-array
0560-subarray-sum-equals-k
0561-array-partition
0594-longest-harmonious-subsequence
0628-maximum-product-of-three-numbers
0645-set-mismatch
0748-largest-number-at-least-twice-of-others
0792-binary-search
0907-koko-eating-bananas
0934-bitwise-ors-of-subarrays
0940-fruit-into-baskets
1056-capacity-to-ship-packages-within-d-days
1137-height-checker
1293-three-consecutive-odds
1350-remove-sub-folders-from-the-filesystem
1402-count-square-submatrices-with-all-ones
1408-find-the-smallest-divisor-given-a-threshold
1426-find-n-unique-integers-sum-up-to-zero
1478-maximum-number-of-events-that-can-be-attended
1510-find-lucky-integer-in-an-array
1548-check-if-all-1s-are-at-least-length-k-places-away
1586-longest-subarray-of-1s-after-deleting-one-element
1603-running-sum-of-1d-array
1605-minimum-number-of-days-to-make-m-bouquets
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1628-count-submatrices-with-all-ones
1646-kth-missing-positive-number
1656-count-good-triplets
1813-maximum-erasure-value
1878-check-if-array-is-sorted-and-rotated
1966-frequency-of-the-most-frequent-element
2048-build-array-from-permutation
2144-maximum-difference-between-increasing-elements
2204-find-subsequence-of-length-k-with-the-largest-sum
2271-rearrange-array-elements-by-sign
2316-count-hills-and-valleys-in-an-array
2320-find-all-k-distant-indices-in-an-array
2387-partition-array-such-that-maximum-difference-is-k
2432-number-of-zero-filled-subarrays
2497-maximum-matching-of-players-with-trainers
2503-longest-subarray-with-maximum-bitwise-and
3074-apple-redistribution-into-boxes
3075-maximize-happiness-of-selected-children
3143-longest-unequal-adjacent-groups-subsequence-i
3154-maximum-value-of-an-ordered-triplet-i
3194-find-words-containing-character
3241-divide-array-into-arrays-with-max-difference
3242-count-elements-with-maximum-frequency
3251-maximum-area-of-longest-diagonal-rectangle
3278-find-the-number-of-ways-to-place-people-i
3461-find-the-minimum-area-to-cover-all-ones-i
3490-find-the-maximum-length-of-valid-subsequence-i
3491-find-the-maximum-length-of-valid-subsequence-ii
3639-zero-array-transformation-i
3743-reschedule-meetings-for-maximum-free-time-i
3747-maximum-difference-between-adjacent-elements-in-a-circular-array
3788-maximum-unique-subarray-sum-after-deletion
3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii

Two Pointers

0011-container-with-most-water
0015-3sum
0018-4sum
0026-remove-duplicates-from-sorted-array
0027-remove-element
0028-find-the-index-of-the-first-occurrence-in-a-string
0031-next-permutation
0042-trapping-rain-water
0075-sort-colors
0080-remove-duplicates-from-sorted-array-ii
0088-merge-sorted-array
0141-linked-list-cycle
0160-intersection-of-two-linked-lists
0202-happy-number
0283-move-zeroes
0287-find-the-duplicate-number
0345-reverse-vowels-of-a-string
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0392-is-subsequence
0455-assign-cookies
0868-push-dominoes
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
2271-rearrange-array-elements-by-sign
2320-find-all-k-distant-indices-in-an-array
2481-strictly-palindromic-number
2497-maximum-matching-of-players-with-trainers

Sorting

0015-3sum
0018-4sum
0049-group-anagrams
0056-merge-intervals
0075-sort-colors
0088-merge-sorted-array
0164-maximum-gap
0169-majority-element
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0220-contains-duplicate-iii
0229-majority-element-ii
0242-valid-anagram
0268-missing-number
0347-top-k-frequent-elements
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0378-kth-smallest-element-in-a-sorted-matrix
0389-find-the-difference
0414-third-maximum-number
0451-sort-characters-by-frequency
0452-minimum-number-of-arrows-to-burst-balloons
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
0900-reordered-power-of-2
1137-height-checker
1478-maximum-number-of-events-that-can-be-attended
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1966-frequency-of-the-most-frequent-element
2204-find-subsequence-of-length-k-with-the-largest-sum
2387-partition-array-such-that-maximum-difference-is-k
2497-maximum-matching-of-players-with-trainers
3074-apple-redistribution-into-boxes
3075-maximize-happiness-of-selected-children
3241-divide-array-into-arrays-with-max-difference
3278-find-the-number-of-ways-to-place-people-i

String

0008-string-to-integer-atoi
0012-integer-to-roman
0013-roman-to-integer
0014-longest-common-prefix
0022-generate-parentheses
0028-find-the-index-of-the-first-occurrence-in-a-string
0038-count-and-say
0049-group-anagrams
0058-length-of-last-word
0171-excel-sheet-column-number
0242-valid-anagram
0345-reverse-vowels-of-a-string
0389-find-the-difference
0392-is-subsequence
0451-sort-characters-by-frequency
0868-push-dominoes
1264-maximum-number-of-words-you-can-type
1302-delete-characters-to-make-fancy-string
1350-remove-sub-folders-from-the-filesystem
2260-divide-a-string-into-groups-of-size-k
2346-largest-3-same-digit-number-in-string
2483-minimum-penalty-for-a-shop
2886-faulty-keyboard
3143-longest-unequal-adjacent-groups-subsequence-i
3194-find-words-containing-character
3396-valid-word
3617-find-the-original-typed-string-i
3753-maximum-difference-between-even-and-odd-frequency-i
3754-maximum-manhattan-distance-after-k-changes
3872-find-most-frequent-vowel-and-consonant

Greedy

0011-container-with-most-water
0055-jump-game
0135-candy
0410-split-array-largest-sum
0452-minimum-number-of-arrows-to-burst-balloons
0455-assign-cookies
0561-array-partition
1478-maximum-number-of-events-that-can-be-attended
1529-max-difference-you-can-get-from-changing-an-integer
1966-frequency-of-the-most-frequent-element
2387-partition-array-such-that-maximum-difference-is-k
2497-maximum-matching-of-players-with-trainers
2704-maximum-difference-by-remapping-a-digit
3074-apple-redistribution-into-boxes
3075-maximize-happiness-of-selected-children
3143-longest-unequal-adjacent-groups-subsequence-i
3241-divide-array-into-arrays-with-max-difference
3743-reschedule-meetings-for-maximum-free-time-i
3788-maximum-unique-subarray-sum-after-deletion

Hash Table

0001-two-sum
0012-integer-to-roman
0013-roman-to-integer
0041-first-missing-positive
0049-group-anagrams
0073-set-matrix-zeroes
0128-longest-consecutive-sequence
0141-linked-list-cycle
0160-intersection-of-two-linked-lists
0169-majority-element
0202-happy-number
0217-contains-duplicate
0229-majority-element-ii
0242-valid-anagram
0268-missing-number
0347-top-k-frequent-elements
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0389-find-the-difference
0451-sort-characters-by-frequency
0560-subarray-sum-equals-k
0594-longest-harmonious-subsequence
0645-set-mismatch
0900-reordered-power-of-2
0940-fruit-into-baskets
1264-maximum-number-of-words-you-can-type
1510-find-lucky-integer-in-an-array
1813-maximum-erasure-value
2204-find-subsequence-of-length-k-with-the-largest-sum
3242-count-elements-with-maximum-frequency
3753-maximum-difference-between-even-and-odd-frequency-i
3754-maximum-manhattan-distance-after-k-changes
3788-maximum-unique-subarray-sum-after-deletion
3872-find-most-frequent-vowel-and-consonant

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
0081-search-in-rotated-sorted-array-ii
0153-find-minimum-in-rotated-sorted-array
0162-find-peak-element
0268-missing-number
0287-find-the-duplicate-number
0349-intersection-of-two-arrays
0350-intersection-of-two-arrays-ii
0378-kth-smallest-element-in-a-sorted-matrix
0410-split-array-largest-sum
0540-single-element-in-a-sorted-array
0792-binary-search
0907-koko-eating-bananas
1056-capacity-to-ship-packages-within-d-days
1408-find-the-smallest-divisor-given-a-threshold
1605-minimum-number-of-days-to-make-m-bouquets
1621-number-of-subsequences-that-satisfy-the-given-sum-condition
1646-kth-missing-positive-number
1966-frequency-of-the-most-frequent-element
3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii

Divide and Conquer

0004-median-of-two-sorted-arrays
0169-majority-element
0215-kth-largest-element-in-an-array
0347-top-k-frequent-elements

Prefix Sum

0238-product-of-array-except-self
0410-split-array-largest-sum
0560-subarray-sum-equals-k
1603-running-sum-of-1d-array
1966-frequency-of-the-most-frequent-element
2483-minimum-penalty-for-a-shop
3639-zero-array-transformation-i

Backtracking

0022-generate-parentheses

Matrix

0048-rotate-image
0054-spiral-matrix
0073-set-matrix-zeroes
0074-search-a-2d-matrix
0378-kth-smallest-element-in-a-sorted-matrix
1402-count-square-submatrices-with-all-ones
1628-count-submatrices-with-all-ones
3461-find-the-minimum-area-to-cover-all-ones-i

Sliding Window

0220-contains-duplicate-iii
0594-longest-harmonious-subsequence
0867-new-21-game
0940-fruit-into-baskets
1586-longest-subarray-of-1s-after-deleting-one-element
1813-maximum-erasure-value
1966-frequency-of-the-most-frequent-element
3743-reschedule-meetings-for-maximum-free-time-i

Bit Manipulation

0136-single-number
0231-power-of-two
0268-missing-number
0287-find-the-duplicate-number
0338-counting-bits
0342-power-of-four
0371-sum-of-two-integers
0389-find-the-difference
0645-set-mismatch
0934-bitwise-ors-of-subarrays
2503-longest-subarray-with-maximum-bitwise-and
3600-find-the-k-th-character-in-string-game-i

Counting

0169-majority-element
0229-majority-element-ii
0347-top-k-frequent-elements
0451-sort-characters-by-frequency
0594-longest-harmonious-subsequence
0900-reordered-power-of-2
1510-find-lucky-integer-in-an-array
3242-count-elements-with-maximum-frequency
3753-maximum-difference-between-even-and-odd-frequency-i
3754-maximum-manhattan-distance-after-k-changes
3872-find-most-frequent-vowel-and-consonant

Simulation

0054-spiral-matrix
2048-build-array-from-permutation
2260-divide-a-string-into-groups-of-size-k
2271-rearrange-array-elements-by-sign
2886-faulty-keyboard
3600-find-the-k-th-character-in-string-game-i
3790-fruits-into-baskets-ii

Union Find

0128-longest-consecutive-sequence

String Matching

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

Linked List

0021-merge-two-sorted-lists
0083-remove-duplicates-from-sorted-list
0141-linked-list-cycle
0160-intersection-of-two-linked-lists
0328-odd-even-linked-list
1411-convert-binary-number-in-a-linked-list-to-integer

Depth-First Search

0386-lexicographical-numbers
1350-remove-sub-folders-from-the-filesystem

Trie

0014-longest-common-prefix
0386-lexicographical-numbers
1350-remove-sub-folders-from-the-filesystem

Brainteaser

0292-nim-game
2481-strictly-palindromic-number
2503-longest-subarray-with-maximum-bitwise-and

Game Theory

0292-nim-game

Counting Sort

0561-array-partition
1137-height-checker

Heap (Priority Queue)

0215-kth-largest-element-in-an-array
0347-top-k-frequent-elements
0378-kth-smallest-element-in-a-sorted-matrix
0451-sort-characters-by-frequency
0506-relative-ranks
1478-maximum-number-of-events-that-can-be-attended
2204-find-subsequence-of-length-k-with-the-largest-sum

Quickselect

0215-kth-largest-element-in-an-array
0347-top-k-frequent-elements

Bucket Sort

0164-maximum-gap
0220-contains-duplicate-iii
0347-top-k-frequent-elements
0451-sort-characters-by-frequency

Radix Sort

0164-maximum-gap

Ordered Set

0220-contains-duplicate-iii
3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii

Enumeration

0900-reordered-power-of-2
1656-count-good-triplets
3278-find-the-number-of-ways-to-place-people-i

Segment Tree

3790-fruits-into-baskets-ii
3791-fruits-into-baskets-iii

Probability and Statistics

0826-soup-servings
0867-new-21-game

Stack

0042-trapping-rain-water
1628-count-submatrices-with-all-ones

Monotonic Stack

0042-trapping-rain-water
1628-count-submatrices-with-all-ones

Geometry

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