Power of LeetCode-326-3

Power of 3

Title description: Given an integer, write a function to determine whether it is a power of 3. If yes, return true; otherwise, return false.

If the integer n is a power of 3, it must satisfy: there is an integer x such that n == $3^{x}$

Please refer to LeetCode official website for example description.

Source: LeetCode
Link: https://leetcode-cn.com/problems/power-of-three/
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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 3, return false directly;
• Otherwise, reset n to n/3 , and then proceed to the next round of processing;
• The condition for the end of the loop is that n is less than 3.

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

public class LeetCode_326 {

    /**
     * 循环
     *
     * @param n
     * @return
     */
    public static boolean isPowerOfThree(int n) {
        // 如果n等于0，则直接返回false
        if (n == 0) {
            return false;
        }
        while (n >= 3) {
            // 如果n不能被3整除，则直接返回false
            if (n % 3 != 0) {
                return false;
            }
            n = n / 3;
        }
        if (n == 1) {
            return true;
        } else {
            return false;
        }
    }

    public static void main(String[] args) {
        System.out.println(isPowerOfThree(45));
    }
}

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