~~~~~ static ArrayList qu= new ArrayList<>(); static void pre(int n) { int i=1; while(i<= n) { qu.add(i); i*=2; } } static void solve(int cct, int tcc) throws IOException {

int n= in.nextInt();
    pre(n);
    HashSet<Integer> fin= new HashSet<>();
    HashSet<Integer> one = new HashSet<>();
    HashSet<Integer>zero = new HashSet<>();
    StringBuilder ans= new StringBuilder();
    for(int i=1;i<n;i++)
    {
        fin.add(i);
    }
    int sc=1;
    for(int i : qu)
    {

        for(int j : fin)
        {
            out.println("? "+j+" "+i);
            out.flush();
            int x = in.nextInt();
            if(x==0)zero.add(j);
            else
                one.add(j);

        }

// out.print(zero); // out.println(one);

if(zero.size()<one.size())
        {
            ans.insert(0, '0');

            fin=zero;
            if(fin.isEmpty()){
                break;
            }
        }
        else if(zero.size()== one.size())
        {
            ans.insert(0,sc);
            if(sc==0)
                fin=zero;
            else
                fin=one;
        }
        else
        {
            ans.insert(0, '1');
            fin=one;
            if(fin.isEmpty()){
                ans.insert(0,'0');
                break;
            }

        }
        sc++;
        sc= sc%2;


        one=new HashSet<>();
        zero=new HashSet<>();

// out.println(fin); // out.println(ans); } // out.println(ans); String a =""; for(int i=0;i<ans.length();i++) { if(ans.charAt(i)=='1') { a=ans.substring(i); break; } }

int number = Integer.parseInt(a, 2);
        out.println("! "+number);



    out.flush();

// 1 2 4 3 5

}~~~~~

Can someone please let me know whats wrong with this solution of D ????

It is failing for 1 2 3 4 5 But on IDE i got correct answer