Coding Problems

“Step-by-Step Solutions to Common Coding Interview Problems”

Array Problems

Problem	Category	Source	Difficulty
Coding Interview - Finding Second Minimum	Sorting	Coding Interview	Easy
Leetcode 33 - Search in Rotated Sorted Array	Binary Search	Leetcode	Medium
Leetcode 49 - Group Anagrams	HashMaps - Prefix Sum	Leetcode	Medium
Leetcode 303 - Range Sum Query Immutable	Arrays - Prefix Sum	Leetcode	Easy
Leetcode 560 - Subarray Sum Equals K	Arrays - Prefix Sum	Leetcode	Medium
Leetcode 1752 - Check if Array Is Sorted and Rotated	Arrays - Sorting	Leetcode	Easy

String Problems

Problem	Category	Source	Difficulty
Leetcode 20 - Valid Parentheses	String - Stack	Leetcode	Easy

Tree & Graph Problems

Problem	Category	Source	Difficulty
Leetcode 102 - Binary Tree Level Order Traversal	Tree - Binary Tree - Breadth First Search	Leetcode	Medium
Leetcode 547 - Number of Provinces	Graph Theory - Union Find	Leetcode	Medium
HackerRank - Roads and Libraries	Graph Theory - Union Find	HackerRank	Medium
Leetcode 721 - Accounts Merge - DFS	Union Find - Depth First Search - Breadth First Search	Leetcode	Medium
Leetcode 721 - Accounts Merge - Union Find	Union Find - Depth First Search - Breadth First Search	Leetcode	Medium

Matrix Problems

Problem	Category	Source	Difficulty
Leetcode Leetcode 733 - Flood Fill	Array - Matrix - Depth First Search - Breadth First Search	Leetcode	Medium
Leetcode 200 - Number of Islands	Array - Matrix - Depth First Search - Breadth First Search	Leetcode	Medium