leetcode-Ugly Number

Question：

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.

Solution：

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

總結:

注意while判斷條件是num！=1，而不是 num ！= 0