2015年8月29日星期六

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.

public class Solution {
    public boolean isUgly(int num) {
        if (num <= 0) {
            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;
    }
}

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