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.
Example 1:
Input: 6 Output: true Explanation: 6 = 2 × 3
Example 2:
Input: 8 Output: true Explanation: 8 = 2 × 2 × 2
Example 3:
Input: 14 Output: false Explanation: 14 is not ugly since it includes another prime factor 7.
Note:
1is typically treated as an ugly number.- Input is within the 32-bit signed integer range: [−231, 231 − 1].
实现思路：递归实现
class Solution {
public boolean isUgly(int num) {
if(num==0) return false;
if(num==1) return true;
if(num%2==0){
num=num/2;
return isUgly(num);
}
if(num%3==0){
num=num/3;
return isUgly(num);
}
if(num%5==0){
num=num/5;
return isUgly(num);
}
return false;
}
}