LeetCode：263. 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.

假设有个数N，先一直除以2，直到其除不尽，然后得到一个结果N1，一直除以3，直到除不尽，得到一个数N2，再一直除以5，直到除不尽。如果最终得到的结果为1，证明他是ugly number。

AC：

class Solution {public:    bool isUgly(int num) {        if(num>0)        for(int i=2;i<6;i++)            while(num%i==0)            num/=i;        return num==1;    }};