LeetCode 202 | Happy Number | C++ Explained
LeetCode 202: Happy Number – complete explanation in C++.
In this video, I explain how to determine whether a number is a Happy Number using C++, focusing on interview thinking and cycle detection techniques.
You’ll learn:
What a Happy Number is with examples
How repeated digit-square sums work
Hash Set approach to detect cycles
Slow and Fast Pointer (Floyd’s Cycle Detection) approach
Step-by-step example walkthrough
Complete C++ implementation
Time and space complexity analysis
Problem Link:
https://leetcode.com/problems/happy-n...
Timestamps:
00:00 Introduction & Problem Explanation
00:50 Example Walkthrough
03:39 Step-by-Step Logic
05:31 C++ Implementation
06:58 Code Execution & Output
Approaches Covered:
1) Hash Set approach
2) Slow and Fast Pointer approach (Optimal)
Time Complexity: O(log n)
Space Complexity:
Hash Set: O(log n)
Slow & Fast Pointer: O(1)
This is a very common math + cycle detection interview question asked in coding interviews.
This video is useful for:
LeetCode beginners
Math-based interview problems
Cycle detection problems
DSA interview preparation
C++ coding interviews
FAANG interview preparation
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