785 - Grid Colouring, 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;
vector<string> grilla;
vector< pair<int, int> > m;
void dfs(char marcar,int x, int y) {
 if (x >= 0 && x < grilla.size() 
 && y >= 0 && y < grilla[x].size() 
 && grilla[x][y] == 32) {
  grilla[x][y] = marcar;
  dfs(marcar, x - 1, y);
  dfs(marcar, x, y - 1);
  dfs(marcar, x + 1, y);
  dfs(marcar, x, y + 1); 
 }
}
int main() {
 
 #ifdef dennisbot
  freopen("in.in", "r", stdin);
  freopen("ou.out", "w", stdout);
 #endif
 int len = 0;
 char linea[100];
 while (gets(linea) != NULL) {
  if (linea[0] == '_') {
   int n = m.size();
   for (int i = 0; i < n; i++) {
    char marcar = grilla[m[i].first][m[i].second];
    grilla[m[i].first][m[i].second] = 32;
    dfs(marcar, m[i].first, m[i].second);
   }
   n = grilla.size();
   for (int i = 0; i < n; i++) {
    printf("%s\n", grilla[i].c_str());
   }
   puts(linea);
   grilla.clear();
   m.clear();
   continue;
  }
  len = strlen(linea);
  for (int i = 0; i < len; i++) {
   if (linea[i] != 32 && linea[i] != 'X')
    m.push_back(make_pair(grilla.size(), i));
  }
  grilla.push_back(linea);
 }
 return 0;
}