1.描述
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.
2.分析
3.代码
class Solution {
public:
bool isUgly(int num) {
if (num <= 0) return false;
if (num == 1 || num == 2 || num == 3 || num == 5) return true;
while (num % 2 == 0) { num /= 2; }
while (num % 3 == 0) { num /= 3; }
while (num % 5 == 0) { num /= 5; }
if (num != 1 && num != 2 && num != 3 && num != 5) return false;
return true;
}
};
