CC1.1

check_unique.java

import java.util.HashSet;
import java.util.Set;
public class UniqueChar {
    public static boolean check(String s) {
        Set<Character> hashset = new HashSet<Character>();
        for (int i = 0; i < s.length(); i++) {
            if (hashset.contains(s.charAt(i)))
                return false;
            else
               hashset.add(s.charAt(i));
        }
        return true;
    }
    public static void main(String[] args) {
        String s = "this is what i need";
        System.out.println(check(s));
    }
}