/* package codechef; // don’t place package name! */
import java.util.;
import java.lang.;
import java.io.*;
/* Name of the class has to be “Main” only if the class is public. /
class Codechef
{
public static void main (String[] args) throws java.lang.Exception
{
// your code goes here
Scanner sc=new Scanner(System.in);
int t=sc.nextInt();
while(t–>0){
int n=sc.nextInt();
int c=sc.nextInt();
String s=sc.next();
int translator_cost=(n(n+1))/2;
Set st=new HashSet<>();
for(int i=0;i<n;i++){
if(!st.contains(s.charAt(i)))
st.add(s.charAt(i));
}
int learning_cost=(cst.size());
int min=Math.min(translator_cost,
Math.min(c+(n(n-1))/2,learning_cost));
System.out.println(min);
}
}
}
what is wrong in my approach,what i’m missing?