Programación Competitiva

#include <iostream>

using namespace std;
 int dr[] = {1,1,0,-1,-1,-1,0,1};
 int dc[] = {0,1,1,1,0,-1,-1,-1};
 
 int main() {
     int c, f, g[50][50];
     while (cin >> c >> f && !(c == 0 && f == 0)) {
         for (int i = 0; i < f; i++)
             for (int j = 0; j < c; j++)
                 g[i][j] = 0;
 
         int a, cnt = 0;
         cin >> a;
         while (a--) {
             int x, y;
             cin >> y >> x;
             x--, y--;
             if (g[x][y] == 1) cnt--;
             g[x][y] = 2;
             for (int d = 0; d < 8; d++) {
                 int i = x + dr[d], j = y + dc[d];
                 if (0 <= i && i < f && 0 <= j && j < c && g[i][j] == 0) {
                     g[i][j] = 1;
                     cnt++;
                 }
             }
         }
 
         cout << cnt << endl;
     }
 
     return 0;
 }