E

1516343302

tags: Math, Bit Manipulation

跟powerOfThree一样: 可以loop, check mod; 也可以用binary search找合适的数字.

```

/*

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

*/

/*

Similar to powerOfThree. Two ways: 1 divide and check mode; 2. binary search

*/

class Solution {

public boolean isPowerOfTwo(int n) {

if (n <= 0) {

return false;

}

while (n != 1) {

if (n % 2 != 0 || n / 2 == 0) {

return false;

}

n/=2;

}

return true;

}

}

```