Power of Two(算法)

4: $2^2$ true
9: $3^2$ false
16: $4^2$ = $2^4$ true

1.mod;
2.log2 => int;
3.位运算;
x & (x - 1)
判断:
x != 0 && x & (x - 1) == 0

python

def isPowerOfTwo(self, n):
    return n > 0 and not (n & n - 1)

java

bool isPowerOfTwo(int n) {
    return n > 0 && !(n & (n - 1));
}