263. Ugly Number

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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.

 1 bool isUgly(int num) {
 2     int k;
 3     int i;
 4     if(num <= 0)
 5         return 0;
 6     if(1 == num)
 7         return 1;
 8     while(num >= 2 && num % 2 == 0) num /= 2;
 9     while(num >= 3 && num % 3 == 0) num /= 3;
10     while(num >= 5 && num % 5 == 0) num /= 5;
11     return num == 1;
12 }

263. Ugly Number

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原文地址：http://www.cnblogs.com/boluo007/p/5495428.html