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leetcode 0342

admin 11月 13, 2020 0

Desicription

Given an integer (signed 32 bits), write a function to check whether it is a power of 4.

Example 1:

1 2	Input: 16 Output: true

Example 2:

1 2	Input: 5 Output: false

Follow up: Could you solve it without loops/recursion?

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