Power Of Four Problem


Description

LeetCode Problem 342.

Given an integer n, return true if it is a power of four. Otherwise, return false.

An integer n is a power of four, if there exists an integer x such that n == 4^x.

Example 1:

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Input: n = 16
Output: true

Example 2:

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Input: n = 5
Output: false

Example 3:

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Input: n = 1
Output: true

Constraints:

  • -2^31 <= n <= 2^31 - 1


Sample C++ Code

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class Solution {
public:
    bool isPowerOfFour(int num) {
        if (num <= 0)
            return false;
        while (num > 1) {
            if ((num & 3) != 0)
                return false;
            num = num >> 2;
        }
        return true;
    }
};




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