Ugly Number | leetcode 263 【Java解题报告】

Write a program to check whether a given number is an ugly number.

Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. For example, 6, 8 are ugly while 14 is not ugly since it includes another prime factor 7.

Note that 1 is typically treated as an ugly number.

【解题思路】：

将num除以2，将整除结果赋值给num，直到无法被2整除，3、5也同理。最后如果得到结果为1，则返回true，否则返回false。

【代码实现】：

public class Solution {
    public boolean isUgly(int num) {
        if(num == 0) return false;       //之前忘了num=0的情况，超时了
        while(num % 2 == 0) num /= 2;
        while(num % 3 == 0) num /= 3;
        while(num % 5 == 0) num /= 5;
        if(num == 1) return true;
        return false;
    }
}

1012 / 1012 test cases passed.   Runtime: 2 ms

最后，欢迎各位批评指正！