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: according to defination, only be divided by 2,3,5
public boolean isUgly(int num) { if(num<=0) return false; while(num%2 == 0){ num = num/2; } while(num%3 == 0){ num = num/3; } while(num%5 == 0){ num = num/5; } return num == 1; }