A7：丑数

 1 public class Solution {
 2     /**
 3      * @param num an integer
 4      * @return true if num is an ugly number or false
 5      */
 6   public boolean isUgly(int num) {
 7         // Write your code here
 8 
 9         if(num <= 0){
10             return false;
11         }else {
12             int tmp = isDouble(num, 2);
13             if (tmp != 1) {
14                 tmp = isDouble(tmp, 3);
15                 if (tmp != 1) {
16                     tmp = isDouble(tmp, 5);
17                     if (tmp != 1) {
18                         return false;
19                     } else {
20                         return true;
21                     }
22                 } else {
23                     return true;
24                 }
25             } else {
26                 return true;
27             }
28         }
29     }
30 
31     public static int isDouble(int num,int deb){
32 
33         int tmp = num %deb;
34 
35         if( tmp == 0 ){
36             num = num/deb;
37            return isDouble(num,deb);
38         }else {
39             return num;
40         }
41     }
42 }