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
Solution:
class Solution {
public boolean isPowerOfTwo2(int n) {
if (n == 0 ) {
return false;
}
if (n == 1) {
return true;
}
while (n % 2 == 0 && n > 2) {
n = n / 2;
}
return n == 0 || n == 2;
}
public boolean isPowerOfTwo(int n) {
if (n == 0 ) {
return false;
}
if (n == Integer.MIN_VALUE) {
return false;
}
return (n & (n - 1)) == 0;
}
}