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.
Java Solution
public boolean isUgly(int num) { if(num==0) return false; if(num==1) return true; if(num%2==0){ num=num/2; return isUgly(num); } if(num%3==0){ num=num/3; return isUgly(num); } if(num%5==0){ num=num/5; return isUgly(num); } return false; } |