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.

 注意事项

Note that 1 is typically treated as an ugly number.

样例

Given num = 8 return true

Given num = 14 return false

解题

直接递归

public class Solution {    /**     * @param num an integer     * @return true if num is an ugly number or false     */    public boolean isUgly(int num) {        // Write your code here        if(num <=0)            return false;        if(num == 1)            return true;        if(num %2 ==0)            return isUgly(num/2);        if(num %3 ==0)            return isUgly(num/3);        if(num%5 ==0)            return isUgly(num/5);        return false;            }}

while 循环‘

public class Solution {    /**     * @param num an integer     * @return true if num is an ugly number or false     */    public boolean isUgly(int num) {        // Write your code here        if(num <=0)            return false;        while(num %2 ==0)            num/=2;        while(num %3 ==0)            num/=3;        while(num%5 ==0)            num/=5;                    return num==1;            }}