LeetCode Solutions by Darshan

Welcome to my LeetCode solutions repository! This repo contains my solutions to various algorithm and data structure problems from LeetCode, implemented mainly in C++.
The goal of this repo is to track my problem-solving progress, improve my coding skills, and share helpful solutions with the community.

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About

This repository is a personal collection of solutions to LeetCode problems. Each solution aims to provide clear, optimized, and well-commented code for better understanding.
I update this repo regularly as I solve new problems and revise older ones.

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LeetCode Topics

Linked List

0002-add-two-numbers
1267-remove-zero-sum-consecutive-nodes-from-linked-list
2903-insert-greatest-common-divisors-in-linked-list
3501-delete-nodes-from-linked-list-present-in-array

Math

0002-add-two-numbers
0043-multiply-strings
0231-power-of-two
0268-missing-number
0670-maximum-swap
0900-reordered-power-of-2
1018-largest-perimeter-triangle
1426-find-n-unique-integers-sum-up-to-zero
1635-number-of-good-pairs
1642-water-bottles
1889-check-if-number-is-a-sum-of-powers-of-three
2610-closest-prime-numbers-in-range
2649-count-total-number-of-colored-cells
2903-insert-greatest-common-divisors-in-linked-list
3172-divisible-and-non-divisible-sums-difference
3201-distribute-candies-among-children-ii
3227-find-missing-and-repeated-values
3321-type-of-triangle
3336-water-bottles-ii
3515-find-if-digit-game-can-be-won
3581-the-two-sneaky-numbers-of-digitville
3676-smallest-number-with-all-set-bits
3768-check-if-digits-are-equal-in-string-after-operations-i

Recursion

0002-add-two-numbers
0231-power-of-two
1197-parsing-a-boolean-expression
1667-find-kth-bit-in-nth-binary-string

Array

0001-two-sum
0026-remove-duplicates-from-sorted-array
0036-valid-sudoku
0037-sudoku-solver
0041-first-missing-positive
0075-sort-colors
0120-triangle
0121-best-time-to-buy-and-sell-stock
0135-candy
0136-single-number
0167-two-sum-ii-input-array-is-sorted
0169-majority-element
0217-contains-duplicate
0219-contains-duplicate-ii
0268-missing-number
0283-move-zeroes
0287-find-the-duplicate-number
0347-top-k-frequent-elements
0448-find-all-numbers-disappeared-in-an-array
0455-assign-cookies
0611-valid-triangle-number
0645-set-mismatch
0745-find-smallest-letter-greater-than-target
0833-bus-routes
0934-bitwise-ors-of-subarrays
1002-maximum-width-ramp
1018-largest-perimeter-triangle
1249-snapshot-array
1293-three-consecutive-odds
1335-maximum-candies-allocated-to-k-children
1402-count-square-submatrices-with-all-ones
1407-group-the-people-given-the-group-size-they-belong-to
1424-maximum-candies-you-can-get-from-boxes
1426-find-n-unique-integers-sum-up-to-zero
1586-longest-subarray-of-1s-after-deleting-one-element
1635-number-of-good-pairs
1760-check-array-formation-through-concatenation
1834-minimum-number-of-people-to-teach
2023-design-movie-rental-system
2137-final-value-of-variable-after-performing-operations
2170-count-number-of-maximum-bitwise-or-subsets
2265-partition-array-according-to-given-pivot
2308-divide-array-into-equal-pairs
2316-count-hills-and-valleys-in-an-array
2343-count-unguarded-cells-in-the-grid
2478-longest-nice-subarray
2483-task-scheduler-ii
2498-smallest-subarrays-with-maximum-bitwise-or
2503-longest-subarray-with-maximum-bitwise-and
2529-range-product-queries-of-powers
2614-maximum-count-of-positive-integer-and-negative-integer
2689-rearranging-fruits
2707-merge-two-2d-arrays-by-summing-values
2724-convert-an-array-into-a-2d-array-with-conditions
2755-extra-characters-in-a-string
2766-find-the-prefix-common-array-of-two-arrays
2888-minimum-index-of-a-valid-split
3194-find-words-containing-character
3227-find-missing-and-repeated-values
3321-type-of-triangle
3430-count-days-without-meetings
3459-find-the-minimum-area-to-cover-all-ones-ii
3461-find-the-minimum-area-to-cover-all-ones-i
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3501-delete-nodes-from-linked-list-present-in-array
3515-find-if-digit-game-can-be-won
3581-the-two-sneaky-numbers-of-digitville
3610-find-x-sum-of-all-k-long-subarrays-i
3648-find-the-maximum-number-of-fruits-collected
3789-maximize-subarrays-after-removing-one-conflicting-pair
3819-count-covered-buildings
3827-implement-router
3863-power-grid-maintenance

Hash Table

0001-two-sum
0036-valid-sudoku
0037-sudoku-solver
0041-first-missing-positive
0169-majority-element
0217-contains-duplicate
0219-contains-duplicate-ii
0242-valid-anagram
0268-missing-number
0347-top-k-frequent-elements
0448-find-all-numbers-disappeared-in-an-array
0645-set-mismatch
0833-bus-routes
0900-reordered-power-of-2
0920-uncommon-words-from-two-sentences
1218-lowest-common-ancestor-of-deepest-leaves
1249-snapshot-array
1267-remove-zero-sum-consecutive-nodes-from-linked-list
1407-group-the-people-given-the-group-size-they-belong-to
1460-number-of-substrings-containing-all-three-characters
1635-number-of-good-pairs
1760-check-array-formation-through-concatenation
1777-determine-if-two-strings-are-close
1834-minimum-number-of-people-to-teach
2023-design-movie-rental-system
2308-divide-array-into-equal-pairs
2483-task-scheduler-ii
2689-rearranging-fruits
2707-merge-two-2d-arrays-by-summing-values
2724-convert-an-array-into-a-2d-array-with-conditions
2755-extra-characters-in-a-string
2766-find-the-prefix-common-array-of-two-arrays
2888-minimum-index-of-a-valid-split
3227-find-missing-and-repeated-values
3501-delete-nodes-from-linked-list-present-in-array
3581-the-two-sneaky-numbers-of-digitville
3610-find-x-sum-of-all-k-long-subarrays-i
3819-count-covered-buildings
3827-implement-router
3863-power-grid-maintenance

Two Pointers

0026-remove-duplicates-from-sorted-array
0075-sort-colors
0167-two-sum-ii-input-array-is-sorted
0283-move-zeroes
0287-find-the-duplicate-number
0455-assign-cookies
0611-valid-triangle-number
0680-valid-palindrome-ii
1002-maximum-width-ramp
2128-reverse-prefix-of-word
2265-partition-array-according-to-given-pivot
2707-merge-two-2d-arrays-by-summing-values
3683-find-the-lexicographically-largest-string-from-the-box-i

Number Theory

2610-closest-prime-numbers-in-range
2903-insert-greatest-common-divisors-in-linked-list
3768-check-if-digits-are-equal-in-string-after-operations-i

String

0008-string-to-integer-atoi
0043-multiply-strings
0242-valid-anagram
0680-valid-palindrome-ii
0812-rotate-string
0920-uncommon-words-from-two-sentences
1058-lexicographically-smallest-equivalent-string
1197-parsing-a-boolean-expression
1205-defanging-an-ip-address
1304-longest-happy-string
1460-number-of-substrings-containing-all-three-characters
1667-find-kth-bit-in-nth-binary-string
1777-determine-if-two-strings-are-close
2128-reverse-prefix-of-word
2137-final-value-of-variable-after-performing-operations
2755-extra-characters-in-a-string
3194-find-words-containing-character
3312-number-of-changing-keys
3379-score-of-a-string
3683-find-the-lexicographically-largest-string-from-the-box-i
3768-check-if-digits-are-equal-in-string-after-operations-i

Simulation

0043-multiply-strings
1642-water-bottles
1667-find-kth-bit-in-nth-binary-string
2137-final-value-of-variable-after-performing-operations
2265-partition-array-according-to-given-pivot
2343-count-unguarded-cells-in-the-grid
2408-number-of-people-aware-of-a-secret
2483-task-scheduler-ii
3336-water-bottles-ii
3768-check-if-digits-are-equal-in-string-after-operations-i

Combinatorics

3201-distribute-candies-among-children-ii
3768-check-if-digits-are-equal-in-string-after-operations-i

Backtracking

0037-sudoku-solver
2170-count-number-of-maximum-bitwise-or-subsets

Bit Manipulation

0136-single-number
0231-power-of-two
0268-missing-number
0287-find-the-duplicate-number
0645-set-mismatch
0934-bitwise-ors-of-subarrays
2170-count-number-of-maximum-bitwise-or-subsets
2308-divide-array-into-equal-pairs
2478-longest-nice-subarray
2498-smallest-subarrays-with-maximum-bitwise-or
2503-longest-subarray-with-maximum-bitwise-and
2529-range-product-queries-of-powers
2766-find-the-prefix-common-array-of-two-arrays
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3676-smallest-number-with-all-set-bits

Enumeration

0900-reordered-power-of-2
2170-count-number-of-maximum-bitwise-or-subsets
3201-distribute-candies-among-children-ii
3459-find-the-minimum-area-to-cover-all-ones-ii
3683-find-the-lexicographically-largest-string-from-the-box-i
3789-maximize-subarrays-after-removing-one-conflicting-pair

Greedy

0135-candy
0455-assign-cookies
0611-valid-triangle-number
0670-maximum-swap
0680-valid-palindrome-ii
1018-largest-perimeter-triangle
1304-longest-happy-string
1407-group-the-people-given-the-group-size-they-belong-to
1834-minimum-number-of-people-to-teach
2689-rearranging-fruits

Counting

0169-majority-element
0347-top-k-frequent-elements
0900-reordered-power-of-2
0920-uncommon-words-from-two-sentences
1635-number-of-good-pairs
1777-determine-if-two-strings-are-close
2308-divide-array-into-equal-pairs
2614-maximum-count-of-positive-integer-and-negative-integer

Matrix

0036-valid-sudoku
0037-sudoku-solver
1402-count-square-submatrices-with-all-ones
2343-count-unguarded-cells-in-the-grid
3227-find-missing-and-repeated-values
3459-find-the-minimum-area-to-cover-all-ones-ii
3461-find-the-minimum-area-to-cover-all-ones-i
3648-find-the-maximum-number-of-fruits-collected

Binary Search

0167-two-sum-ii-input-array-is-sorted
0268-missing-number
0278-first-bad-version
0287-find-the-duplicate-number
0611-valid-triangle-number
0745-find-smallest-letter-greater-than-target
1249-snapshot-array
1335-maximum-candies-allocated-to-k-children
2498-smallest-subarrays-with-maximum-bitwise-or
2614-maximum-count-of-positive-integer-and-negative-integer
3827-implement-router

Sorting

0075-sort-colors
0169-majority-element
0217-contains-duplicate
0242-valid-anagram
0268-missing-number
0347-top-k-frequent-elements
0455-assign-cookies
0611-valid-triangle-number
0645-set-mismatch
0900-reordered-power-of-2
1018-largest-perimeter-triangle
1777-determine-if-two-strings-are-close
2689-rearranging-fruits
2888-minimum-index-of-a-valid-split
3321-type-of-triangle
3430-count-days-without-meetings
3819-count-covered-buildings

Stack

1002-maximum-width-ramp
1197-parsing-a-boolean-expression
2128-reverse-prefix-of-word

Monotonic Stack

1002-maximum-width-ramp

Sliding Window

0219-contains-duplicate-ii
1460-number-of-substrings-containing-all-three-characters
1586-longest-subarray-of-1s-after-deleting-one-element
2478-longest-nice-subarray
2498-smallest-subarrays-with-maximum-bitwise-or
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3610-find-x-sum-of-all-k-long-subarrays-i

Heap (Priority Queue)

0347-top-k-frequent-elements
1304-longest-happy-string
2023-design-movie-rental-system
3610-find-x-sum-of-all-k-long-subarrays-i
3863-power-grid-maintenance

Queue

2408-number-of-people-aware-of-a-secret
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3827-implement-router

Prefix Sum

2529-range-product-queries-of-powers
3475-minimum-operations-to-make-binary-array-elements-equal-to-one-i
3789-maximize-subarrays-after-removing-one-conflicting-pair

Interactive

0278-first-bad-version

String Matching

0812-rotate-string

Tree

1218-lowest-common-ancestor-of-deepest-leaves

Depth-First Search

1218-lowest-common-ancestor-of-deepest-leaves
3863-power-grid-maintenance

Breadth-First Search

0833-bus-routes
1218-lowest-common-ancestor-of-deepest-leaves
1424-maximum-candies-you-can-get-from-boxes
3863-power-grid-maintenance

Binary Tree

1218-lowest-common-ancestor-of-deepest-leaves

Design

1249-snapshot-array
2023-design-movie-rental-system
3827-implement-router

Dynamic Programming

0120-triangle
0121-best-time-to-buy-and-sell-stock
0934-bitwise-ors-of-subarrays
1402-count-square-submatrices-with-all-ones
1586-longest-subarray-of-1s-after-deleting-one-element
2028-the-earliest-and-latest-rounds-where-players-compete
2408-number-of-people-aware-of-a-secret
2755-extra-characters-in-a-string
2882-ways-to-express-an-integer-as-sum-of-powers
3648-find-the-maximum-number-of-fruits-collected

Trie

2755-extra-characters-in-a-string

Graph

1424-maximum-candies-you-can-get-from-boxes
3863-power-grid-maintenance

Union Find

1058-lexicographically-smallest-equivalent-string
3863-power-grid-maintenance

Memoization

2028-the-earliest-and-latest-rounds-where-players-compete

Segment Tree

3789-maximize-subarrays-after-removing-one-conflicting-pair

Brainteaser

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

Divide and Conquer

0169-majority-element
0347-top-k-frequent-elements

Bucket Sort

0347-top-k-frequent-elements

Quickselect

0347-top-k-frequent-elements

Ordered Set

2023-design-movie-rental-system
3827-implement-router
3863-power-grid-maintenance