题目:
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.
分析:
直接对该数一直除2,3,5即可,直到除完为止,判断最终结果是否等于1,如果等于1,那么return true,否则return false。
代码:
class Solution {
public:
bool isUgly(int num) {
if(num==0)return false;
while(!(num%2))num/=2;
while(!(num%3))num/=3;
while(!(num%5))num/=5;
if(num!=1)return false;
return true;
}
};