Ugly Number

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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.

思路：除以2，3，5直到不能除为止，最后应该是1，要为其他数，则不是ugly number.

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

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