Leetcode 263. Ugly Number

263. Ugly Number

• Total Accepted: 65061
• Total Submissions:173755
• Difficulty: Easy

 

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.

 

 

思路：按定义做。

 

代码：

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