10336 - Rank the Languages, uva, solution

This can be done with both DFS or BSF graph traversal.

#include <iostream> 
#include <sstream> 
#include <cstring> 
#include <cstdio> 
#include <cstdlib> 
#include <algorithm> 
#include <ctime> 
#include <cctype> 
#include <cmath> 
#include <vector> 
#include <map> 
#include <set> 
#include <queue>
#include<bitset>
#define foreach(it, l) for (typeof(l.begin()) it = l.begin(); it != l.end(); it++)
#define db(a) \
cout << #a << " = " << a << endl
#define db2(a, b) \
cout << #a << " = " << a << " " << #b << " = " << b << endl
#define inf (1<<30)
using namespace std;
vector<string> lista;
int h, w;
void dfs(int i, int j, char cur) {
 if (i >= 0 && i < h && j >= 0 && j < w && lista[i][j] == cur) {
  lista[i][j] = '-';
  dfs(i + 1, j, cur);
  dfs(i - 1, j, cur);
  dfs(i, j - 1, cur);
  dfs(i, j + 1, cur);
 }
}
bool def(int i, int j, char cur) {
 if (i > 0 && lista[i - 1][j] == cur) return true;
 if (i < h - 1 && lista[i + 1][j] == cur) return true;
 if (j > 0 && lista[i][j - 1] == cur) return true;
 if (j < w - 1 && lista[i][j + 1] == cur) return true;
 return false;
}
bool cmp(const pair<char, int>& a, const pair<char, int>& b) {
 if (a.second > b.second) return true;
 return a.first < b.first;
}
int main() {
 #ifdef dennisbot
  freopen("in.in", "r", stdin);
  freopen("ou.out", "w", stdout);
 #endif
 int t;
 string s;
 set<char> sc;
 cin >> t;
 int start = t;
 while (t--) {
  cin >> h >> w;
  lista.resize(h);
  for (int i = 0; i < h; i++) {
   cin >> lista[i];
  }
  map<char, int> mapa;
  sc.clear();
  for (int i = 0; i < h; i++) {
   for (int j = 0; j < w; j++) {
    if (lista[i][j] != '-' && def(i, j, lista[i][j])) {
     char cur = lista[i][j];
     mapa[cur]++;
     sc.insert(cur);
     dfs(i, j, cur);
    }
   }
  }
  printf("World #%d\n", start - t);
  vector< pair<char,int> > res;
  foreach(it, mapa) {
   res.push_back(make_pair(it->first, it->second));
  }
  sort(res.begin(), res.end(), cmp);
  for (int i = 0; i < res.size(); i++) {
   cout << res[i].first << ": " << res[i].second << endl;
  }
 }
 return 0;
}