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(easy)LeetCode 263.Ugly Number

Posted on 2015-08-19 16:54  骄阳照林  阅读(117)  评论(0编辑  收藏  举报

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.

Credits:
Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.

代码如下:

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

  运行结果: