Power of Two

Problem

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.

Follow up: Could you solve it without loops/recursion?

Constraints

• -231 <= nums[i] <= 231 - 1

Solution

The problem Power of Two can be solved by examining bits in the given number. If and only if a given integer is a power of two, then subtracting 1 from the number and performing a bitwise and operation on 2 numbers will result in 0.

Implementation

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