[LeetCode]Power of Four

和Power of Two类似的，我们只需要在其基础上确保其为1的位在第0,2,4...位上即可，代码如下：

	class Solution {
	public:
	bool isPowerOfFour(int num) {
	int mask = 0x55555555;
	return (num & mask) && !(num & (num - 1));
	}
	};

view raw Power of Four.cpp hosted with ❤ by GitHub