import java.util.*;
public class isUnique {
public static boolean isUnique1(String str) {
int len = str.length();
boolean[] charcontains = new boolean[256];// set up a boolean array
for(int i = 0; i<len;i++){
int val = str.charAt(i);//ascii two code number
if(charcontains[val]) return false; // if contains return false
charcontains[val] = true; // first letter sets to be true
}
return true;
}
public static void main(String[] args){
String str = "abcda";
System.out.println(isUnique1(str));
}
}