LeetCode263——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.

实现：

class Solution {

public:

bool isUgly(int num) {

if (num == 0) return false;

if (num == 1) return true;

if (num % 2 == 0) return isUgly(num/2);

else if (num % 3 == 0) return isUgly(num/3);

else if (num % 5 == 0) return isUgly(num/5);

return false;

}

};