231 - Power of Two

231. Power of Two

Problem Statement:

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

Constraints:

• -2³¹ <= n <= 2³¹ - 1

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

Solution:

Java

public boolean isPowerOfTwo(int n) {
  if (n == 0)
    return false;
  long x = (long) n;
  return (x & x - 1) == 0;
}

...