5. Power of Two

Given an integer n, return true if it is a power of two. Otherwise, return false.

An integer n is a power of two, if there exists an integer x such that n == 2x.

Example 1:
Input: n = 1
Output: true
Explanation: 20 = 1

Example 2:
Input: n = 16
Output: true
Explanation: 24 = 16

Example 3:
Input: n = 3
Output: false

Example 4:
Input: n = 4
Output: true

Example 5:
Input: n = 5
Output: false

Solution: (Using Bitwise operations)

Power of 2 has only one set bit Counting number of set bits approach

class Solution
{
public:
    bool isPowerOfTwo(int n)
    {

        if (n <= 0)
        {
            return false;
        }

        n = n & n - 1;
        if (n == 0)
        {
            return true;
        }

        return false;
    }
};

Time Complexity: O(1)