English
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;
}
...