231. Power of Two

[Subhosjx]

PR Title Format: Problem no.Problem name.cpp

Approach

• A number n is a power of two if:

  • n > 0
  • In binary, it has exactly one set bit.

• Trick: For powers of two, n & (n - 1) == 0.

Example:

• n = 8 (1000), n-1 = 7 (0111), n & (n-1) = 0000 ✅
• n = 6 (0110), n-1 = 5 (0101), n & (n-1) = 0100 ❌

Intuition

Binary representation of powers of two looks like: 1 (0001), 2 (0010), 4 (0100), 8 (1000), 16 (10000) ...

Each has exactly one set bit.
Therefore, checking (n > 0) && (n & (n-1)) == 0 efficiently verifies this.

Code Solution (C++)

    class Solution {
public:
    bool isPowerOfTwo(int n) {
        if (n <= 0) return false;
        return (n & (n - 1)) == 0;
    }
};
    

Related Issues #109

By submitting this PR, I confirm that:

• This is my original work not totally AI generated
• I have tested the solution thoroughly on leetcode
• I have maintained proper PR description format
• This is a meaningful contribution, not spam

Summary by Sourcery

New Features:

• Add isPowerOfTwo function in Solution class utilizing n > 0 and n & (n - 1) == 0 to verify powers of two

[sourcery-ai]

Reviewer's guide (collapsed on small PRs)

Reviewer's Guide

Adds a new Solution method that efficiently determines if an integer is a power of two using a bitwise trick.

Class diagram for the new Solution class with isPowerOfTwo method

classDiagram
class Solution {
  +bool isPowerOfTwo(int n)
}

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Flow diagram for isPowerOfTwo logic

flowchart TD
    A["Input: n"] --> B["n <= 0?"]
    B -- Yes --> C["Return false"]
    B -- No --> D["Compute n & (n-1)"]
    D --> E["Result == 0?"]
    E -- Yes --> F["Return true"]
    E -- No --> G["Return false"]

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File-Level Changes

Change	Details	Files
Implement isPowerOfTwo method with bitwise check	Created Solution class with public isPowerOfTwo(int) signature Added guard clause returning false for non-positive inputs Added (n & (n - 1)) == 0 check to verify single set bit	231. Power of Two.cpp

Possibly linked issues

• 112.PathSum.cpp #231: The PR implements the exact solution for the 'Power of Two' problem described in the issue.

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[github-actions]

🎉 Congrats on getting your PR merged in, @Subhosjx! 🙌🏼

Thanks for your contribution every effort helps improve the project.

Looking forward to seeing more from you! 🥳✨