Power of LeetCode-342-4

Power of 4

Title description: Given an integer, write a function to determine whether it is a power of 4. If yes, return true; otherwise, return false.

If the integer n is a power of 4, it must satisfy: there is an integer x such that n == $4^{x}$

Please refer to the official website of LeetCode for examples.

Source: LeetCode
Link: https://leetcode-cn.com/problems/power-of-four/
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Solution 1: Round Robin

First, if n is equal to 0, then return false directly.

If n is not equal to 0, the loop processing is performed, and the processing procedure is as follows:

• If n is not divisible by 4, return false directly;
• Otherwise, reset n to n/4 , and then proceed to the next round of processing;
• The condition for the end of the loop is that n is less than 4.

Finally, it is judged that if n is equal to 1, it returns true; otherwise, it returns false.

: and -326-3 161472652aa51f is exactly the same.

public class LeetCode_342 {
    public static boolean isPowerOfFour(int n) {
        // 4的任何次幂都不可能为0，所以直接直接返回false
        if (n == 0) {
            return false;
        }
        while (n >= 4) {
            if (n % 4 != 0) {
                return false;
            }
            n = n / 4;
        }
        if (n == 1) {
            return true;
        } else {
            return false;
        }
    }

    public static void main(String[] args) {
        System.out.println(isPowerOfFour(16));
    }
}

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