- DSA Problems
First Unique Character in a String Algorithm
Find the first non-repeating character in a string and return its index, with optimal time and space complexity solutions.
- DSA Problems
Prefix Sum with Hash Map Patterns in Java
Comprehensive guide to solving array and subarray problems using prefix sum techniques with hash map optimizations for efficient runtime complexity.
- DSA Problems
Four Sum Problem Solution with Two Pointers Approach
Complete Java implementation of 4Sum problem using sorting and two-pointer technique with O(n³) time complexity and O(1) space solution.
- DSA Problems
Happy Number Algorithm Solution
Complete Java implementation for determining happy numbers with optimal time and space complexity analysis.
- DSA Problems
Contains Duplicate Problem Solution
Complete Java implementation for detecting duplicate elements in an array with optimal time and space complexity analysis.
- DSA Problems
Isomorphic Strings Java Solution with HashMap
Complete Java implementation for determining if two strings are isomorphic, using character mapping with HashMap for optimal time and space complexity.
- DSA Problems
Find the Index of the First Occurrence in a String
Learn to implement string matching algorithms including KMP and naive approaches to find the first occurrence of a substring in a string.
- DSA Problems
Decode String Algorithm Solution
Java implementation of decode string problem with stack-based approach for handling nested encoded patterns.
- DSA Problems
Compare Version Numbers Java Solution
Complete Java implementation to compare version numbers with proper edge case handling and performance considerations.
- DSA Problems
Longest Palindromic Substring Algorithm Solution
Complete Java implementation with optimal time and space complexity for finding the longest palindromic substring using expand around centers approach.
- DSA Problems
String to Integer Conversion Algorithm
Implementation of atoi function converting strings to 32-bit signed integers with overflow handling and edge case management.
- DSA Problems
Group Anagrams Problem Solution
Complete Java implementation for grouping anagrams from a string array, including optimal approach and time/space complexity analysis.
FAANG Data Structures & Algorithms Problems Guide
A curated catalog of concrete data structures and algorithms problems. Use it to plan practice, track coverage, and rehearse solutions with a repeatable approach.