模拟 Codeforces Round #288 (Div. 2) A. Pasha and Pixels

题目传送门

 /*
     模拟水题：给定n*m的空白方格，k次涂色，将（x，y）处的涂成黑色，判断第几次能形成2*2的黑色方格，若不能，输出0
     很挫的判断四个方向是否OK
 */
 #include <cstdio>
 #include <iostream>
 #include <algorithm>
 #include <cmath>
 #include <cstring>
 #include <map>
 using namespace std;

 const int MAXN = 1e3 + ;
 const int INF = 0x3f3f3f3f;
 int a[MAXN][MAXN];

 bool lose(int i, int j, int n, int m)
 {
     if (a[i][j] == )
     {
         if (j < m && a[i][j+] == )
         {
             if (i < n && a[i+][j] == )
             {
                 if (a[i+][j+] == )
                 {
                     return true;
                 }
             }
         }
         if (j> && a[i][j-] == )
         {
             if (i < n && a[i+][j-] == )
             {
                 if (a[i+][j] == )
                 {
                     return true;
                 }
             }
         }
         if (j >  && a[i][j-] == )
         {
             if (i >  && a[i-][j-] == )
             {
                 if (a[i-][j] == )
                 {
                     return true;
                 }
             }
         }
         if (j < m && a[i][j+] == )
         {
             if (i >  && a[i-][j] == )
             {
                 if (a[i-][j+] == )
                 {
                     return true;
                 }
             }
         }
     }

     return false;
 }

 int main(void)
 {
     #ifndef ONLINE_JUDGE
         freopen ("A.in", "r", stdin);
     #endif

     int n, m, k;
     while (~scanf ("%d%d%d", &n, &m, &k))
     {
         memset (a, , sizeof (a));

         bool flag = false;    int ans = -;
         for (int i=; i<=k; ++i)
         {
             int x, y;
             scanf ("%d%d", &x, &y);
             if (a[x][y] == )    continue;

             a[x][y] = ;
             if (lose (x, y, n, m) && !flag)
             {
                 flag = true;    ans = i;
             }
         }

         if (!flag)    printf ("%d\n", );
         else    printf ("%d\n", ans);
     }

     return ;
 }