ricorsiva

#include <iostream>
using namespace std;

int S(int *X, int i){

    if(X[0]==-2)
    return -2;

    if(X[0]==-1)
    i--;

    if(!i){

        if(X[1]==-2)
        return -2;

        return 1;
    }


    int r=S(X+1, i);

    if(r==-2)
    return -2;

    return 1+r;
}

int main(){

   int X[100];
   cin>>X[0];

   for(int i=1; i<100 && X[i-1]!=-2; i++)
   cin>>X[i];

   int a;
   cin>>a;

   int b=S(X,a);

   if(b==-2)
     cout<<"sottosequenza "<<a<<" non presente"<<endl;
   else
     cout<<"inizio sottosequenza "<<a<<" indice="<<b<<endl;


   cout<<"end"<<endl;

 }