LeetCode题解：Ugly Number

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.

题意：判断一个给定整数的质因数是否只有2，3，5。其中1符合题意

解决思路：循环除以质因数2，3，5。最后结果为1则符合题意

代码：

public class Solution {    public boolean isUgly(int num) {        if(num < 1){            return false;        }        while(num != 1){            if(num % 2 == 0){                num /= 2;            }else if(num % 3 == 0){                num /= 3;            }else if(num % 5 == 0){                num /= 5;            }else{                return false;            }        }        return true;    }}