LeetCode-Solutions

Collection of LeetCode questions to ace the coding interview! - Created using LeetHub-3.0

LeetCode Topics

Array

Problem Name	Difficulty
0001-two-sum	Easy
0004-median-of-two-sorted-arrays	Hard
0011-container-with-most-water	Medium
0014-longest-common-prefix	Easy
0015-3sum	Medium
0016-3sum-closest	Medium
0026-remove-duplicates-from-sorted-array	Easy
0027-remove-element	Easy
0035-search-insert-position	Easy
0066-plus-one	Easy
0088-merge-sorted-array	Easy
0108-convert-sorted-array-to-binary-search-tree	Easy
0118-pascals-triangle	Easy
0119-pascals-triangle-ii	Easy
0121-best-time-to-buy-and-sell-stock	Easy
0136-single-number	Easy
0169-majority-element	Easy
1488-avoid-flood-in-the-city	Medium
1727-largest-submatrix-with-rearrangements	Medium
1878-get-biggest-three-rhombus-sums-in-a-grid	Medium
2011-final-value-of-variable-after-performing-operations	Easy
3070-count-submatrices-with-top-left-element-and-sum-less-than-k	Medium
3147-taking-maximum-energy-from-the-mystic-dungeon	Medium
3212-count-submatrices-with-equal-frequency-of-x-and-y	Medium
3296-minimum-number-of-seconds-to-make-mountain-height-zero	Medium

Hash Table

Problem Name	Difficulty
0001-two-sum	Easy
0003-longest-substring-without-repeating-characters	Medium
0012-integer-to-roman	Medium
0013-roman-to-integer	Easy
0141-linked-list-cycle	Easy
0160-intersection-of-two-linked-lists	Easy
0169-majority-element	Easy
0202-happy-number	Easy
1488-avoid-flood-in-the-city	Medium

String

Problem Name	Difficulty
0003-longest-substring-without-repeating-characters	Medium
0005-longest-palindromic-substring	Medium
0006-zigzag-conversion	Medium
0008-string-to-integer-atoi	Medium
0010-regular-expression-matching	Hard
0012-integer-to-roman	Medium
0013-roman-to-integer	Easy
0014-longest-common-prefix	Easy
0020-valid-parentheses	Easy
0028-find-the-index-of-the-first-occurrence-in-a-string	Easy
0058-length-of-last-word	Easy
0067-add-binary	Easy
0125-valid-palindrome	Easy
1415-the-k-th-lexicographical-string-of-all-happy-strings-of-length-n	Medium
1758-minimum-changes-to-make-alternating-binary-string	Easy
2011-final-value-of-variable-after-performing-operations	Easy
3461-check-if-digits-are-equal-in-string-after-operations-i	Easy

Sliding Window

Problem Name	Difficulty
0003-longest-substring-without-repeating-characters	Medium

Math

Problem Name	Difficulty
0002-add-two-numbers	Medium
0007-reverse-integer	Medium
0009-palindrome-number	Easy
0012-integer-to-roman	Medium
0013-roman-to-integer	Easy
0066-plus-one	Easy
0067-add-binary	Easy
0069-sqrtx	Easy
0070-climbing-stairs	Easy
0202-happy-number	Easy
1622-fancy-sequence	Hard
1878-get-biggest-three-rhombus-sums-in-a-grid	Medium
3296-minimum-number-of-seconds-to-make-mountain-height-zero	Medium
3461-check-if-digits-are-equal-in-string-after-operations-i	Easy

Binary Search

Problem Name	Difficulty
0004-median-of-two-sorted-arrays	Hard
0035-search-insert-position	Easy
0069-sqrtx	Easy
1488-avoid-flood-in-the-city	Medium
3296-minimum-number-of-seconds-to-make-mountain-height-zero	Medium

Greedy

Problem Name	Difficulty
0011-container-with-most-water	Medium
1488-avoid-flood-in-the-city	Medium
1727-largest-submatrix-with-rearrangements	Medium
3296-minimum-number-of-seconds-to-make-mountain-height-zero	Medium

Heap (Priority Queue)

Problem Name	Difficulty
1488-avoid-flood-in-the-city	Medium
1878-get-biggest-three-rhombus-sums-in-a-grid	Medium
3296-minimum-number-of-seconds-to-make-mountain-height-zero	Medium

Dynamic Programming

Problem Name	Difficulty
0005-longest-palindromic-substring	Medium
0010-regular-expression-matching	Hard
0070-climbing-stairs	Easy
0118-pascals-triangle	Easy
0119-pascals-triangle-ii	Easy
0121-best-time-to-buy-and-sell-stock	Easy
3147-taking-maximum-energy-from-the-mystic-dungeon	Medium

Prefix Sum

Problem Name	Difficulty
1878-get-biggest-three-rhombus-sums-in-a-grid	Medium
3070-count-submatrices-with-top-left-element-and-sum-less-than-k	Medium
3147-taking-maximum-energy-from-the-mystic-dungeon	Medium
3212-count-submatrices-with-equal-frequency-of-x-and-y	Medium

Trie

Problem Name	Difficulty
0014-longest-common-prefix	Easy

Stack

Problem Name	Difficulty
0020-valid-parentheses	Easy
0094-binary-tree-inorder-traversal	Easy
0144-binary-tree-preorder-traversal	Easy
0145-binary-tree-postorder-traversal	Easy

Two Pointers

Problem Name	Difficulty
0005-longest-palindromic-substring	Medium
0011-container-with-most-water	Medium
0015-3sum	Medium
0016-3sum-closest	Medium
0026-remove-duplicates-from-sorted-array	Easy
0027-remove-element	Easy
0028-find-the-index-of-the-first-occurrence-in-a-string	Easy
0088-merge-sorted-array	Easy
0125-valid-palindrome	Easy
0141-linked-list-cycle	Easy
0160-intersection-of-two-linked-lists	Easy
0202-happy-number	Easy

String Matching

Problem Name	Difficulty
0028-find-the-index-of-the-first-occurrence-in-a-string	Easy

Linked List

Problem Name	Difficulty
0002-add-two-numbers	Medium
0021-merge-two-sorted-lists	Easy
0083-remove-duplicates-from-sorted-list	Easy
0141-linked-list-cycle	Easy
0160-intersection-of-two-linked-lists	Easy
0203-remove-linked-list-elements	Easy

Recursion

Problem Name	Difficulty
0002-add-two-numbers	Medium
0010-regular-expression-matching	Hard
0021-merge-two-sorted-lists	Easy
0203-remove-linked-list-elements	Easy

Divide and Conquer

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

Bit Manipulation

Problem Name	Difficulty
0067-add-binary	Easy
0136-single-number	Easy
0190-reverse-bits	Easy
0191-number-of-1-bits	Easy

Simulation

Problem Name	Difficulty
0067-add-binary	Easy
2011-final-value-of-variable-after-performing-operations	Easy
3461-check-if-digits-are-equal-in-string-after-operations-i	Easy

Sorting

Problem Name	Difficulty
0015-3sum	Medium
0016-3sum-closest	Medium
0088-merge-sorted-array	Easy
0169-majority-element	Easy
1727-largest-submatrix-with-rearrangements	Medium
1878-get-biggest-three-rhombus-sums-in-a-grid	Medium

Memoization

Problem Name	Difficulty
0070-climbing-stairs	Easy

Tree

Problem Name	Difficulty
0094-binary-tree-inorder-traversal	Easy
0100-same-tree	Easy
0101-symmetric-tree	Easy
0104-maximum-depth-of-binary-tree	Easy
0108-convert-sorted-array-to-binary-search-tree	Easy
0110-balanced-binary-tree	Easy
0111-minimum-depth-of-binary-tree	Easy
0112-path-sum	Easy
0144-binary-tree-preorder-traversal	Easy
0145-binary-tree-postorder-traversal	Easy

Depth-First Search

Problem Name	Difficulty
0094-binary-tree-inorder-traversal	Easy
0100-same-tree	Easy
0101-symmetric-tree	Easy
0104-maximum-depth-of-binary-tree	Easy
0110-balanced-binary-tree	Easy
0111-minimum-depth-of-binary-tree	Easy
0112-path-sum	Easy
0144-binary-tree-preorder-traversal	Easy
0145-binary-tree-postorder-traversal	Easy

Binary Tree

Problem Name	Difficulty
0094-binary-tree-inorder-traversal	Easy
0100-same-tree	Easy
0101-symmetric-tree	Easy
0104-maximum-depth-of-binary-tree	Easy
0108-convert-sorted-array-to-binary-search-tree	Easy
0110-balanced-binary-tree	Easy
0111-minimum-depth-of-binary-tree	Easy
0112-path-sum	Easy
0144-binary-tree-preorder-traversal	Easy
0145-binary-tree-postorder-traversal	Easy

Breadth-First Search

Problem Name	Difficulty
0100-same-tree	Easy
0101-symmetric-tree	Easy
0104-maximum-depth-of-binary-tree	Easy
0111-minimum-depth-of-binary-tree	Easy
0112-path-sum	Easy

Binary Search Tree

Problem Name	Difficulty
0108-convert-sorted-array-to-binary-search-tree	Easy

Counting

Problem Name	Difficulty
0169-majority-element	Easy

Matrix

Problem Name	Difficulty
1727-largest-submatrix-with-rearrangements	Medium
1878-get-biggest-three-rhombus-sums-in-a-grid	Medium
3070-count-submatrices-with-top-left-element-and-sum-less-than-k	Medium
3212-count-submatrices-with-equal-frequency-of-x-and-y	Medium

Design

Problem Name	Difficulty
1622-fancy-sequence	Hard

Segment Tree

Problem Name	Difficulty
1622-fancy-sequence	Hard

Backtracking

Problem Name	Difficulty
1415-the-k-th-lexicographical-string-of-all-happy-strings-of-length-n	Medium

Combinatorics

Problem Name	Difficulty
3461-check-if-digits-are-equal-in-string-after-operations-i	Easy

Number Theory

Problem Name	Difficulty
3461-check-if-digits-are-equal-in-string-after-operations-i	Easy