231. Power of Two

• Difficulty: Easy

• Topics: Math, Bit Manipulation

• Similar Questions:

  • Number of 1 Bits

  • Power of Three

  • Power of Four

Problem:

Given an integer, write a function to determine if it is a power of two.

Example 1:

Input: 1
Output: true 
Explanation: 20 = 1

Example 2:

Input: 16
Output: true
Explanation: 24 = 16

Example 3:

Input: 218
Output: false

Solutions:

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