class BinarySearch {

public:

    int getPos(vector<int> A, int n, int val) {

        // write code here

      

        if(n==0)

            return -1;

        else

            return find(A,0,A.size(),val);

     }

   

    int find(vector <int> A,int a,int b,int val)

        {

         int low=a;

         int high=b;

          if(low>high)

              return -1;

          else

               {

                int mid=(high+low)/2;

                if(A[mid]==val)

                    return mid;

                else

                    {

                     if(A[mid]>val)

                       return find(A,mid+1,high,val);

                    else

                       return find(A,low,mid-1,val);

                    }    

               }      

    }

   

};