679 - Dropping Balls, uva

#include<iostream>
#include<cstdio>
#include<cstring>
#include<vector>
#include<utility>
#define db(a) cout << #a << " = " << a << endl
#define db2(a, b) cout << #a << " = " << a << " " << #b << " = " << b << endl
using namespace std;
int bin_to_entero(string binario) {
 int n = binario.size();
 int t = 1, res = 0;
 for (int i = n - 1; i >= 0; i--) {
  res += t * (binario[i] - 48);
  t *= 2;
 }
 return res;
}
int main() {
 vector< vector<string> > level;
 #ifdef dennisbot
  freopen("in.in", "r", stdin);
  freopen("ou.out", "w", stdout);
 #endif
 vector<string> seed;
 seed.push_back("10");
 seed.push_back("11");
 level.push_back(seed);
 int t = 2;
 for (int k = 3; k < 21; k++) {
  vector<string> fila;
  for (int i = 0; i < t; i++) {
   fila.push_back(level[k - 3][i] + "0");
  }
  for (int i = 0; i < t; i++) {
   fila.push_back(level[k - 3][i] + "1");
  }
  level.push_back(fila);
  t *= 2;
 }
 int n, D, I;
 scanf("%d", &n);
 for (int i = 0; i < n; i++) {
  scanf("%d%d", &D, &I);
  printf("%d\n", bin_to_entero(level[D - 2][I - 1]));
 }
 scanf("%d", &n);
 return 0;
}