func_code_string: #include <bits/stdc++.h>   using namespace std;   bool M[3000][6000];   int dr[] = {-1, -1, -1, 0, 0, 1, 1, 1};   int dc[] = {-1, 0, 1, -1, 1, -1, 0, 1};   int parent[18000000];   int Find(int x) {     if (parent[x] != x) parent[x] = Find(parent[x]);     return parent[x];   }   void Union(int x, int y) {     x = Find(x);     y = Find(y);     parent[x] = y;   }   int R, C;   int id(int r, int c) { return r * 2 * C + c; }   int main() {     int N, r, c;     scanf( %d %d %d , &R, &C, &N);     if (C == 1)       printf( 0 n );     else {       for (int i = R * 2 * C - 1; i >= 0; --i) parent[i] = i;       int ans = 0;       while (N--) {         scanf( %d %d , &r, &c);         --r;         --c;         bool add = true;         for (int k1 = 0; k1 < 8; ++k1) {           int r2 = r + dr[k1], c2 = c + dc[k1];           if (c2 == -1) c2 = 2 * C - 1;           if (c2 == 2 * C) c2 = 0;           if (r2 >= 0 && r2 < R && M[r2][c2]) {             int u = id(r2, c2);             for (int k2 = 0; k2 < 8; ++k2) {               int r3 = r + dr[k2], c3 = c + C + dc[k2];               if (c3 == -1) c3 = 2 * C - 1;               if (c3 == 2 * C) c3 = 0;               if (r3 >= 0 && r3 < R && M[r3][c3]) {                 int v = id(r3, c3);                 if (Find(u) == Find(v)) add = false;               }             }           }         }         if (add) {           ++ans;           M[r][c] = M[r][c + C] = true;           for (int k = 0; k < 8; ++k) {             int r2 = r + dr[k], c2 = c + dc[k];             if (c2 == -1) c2 = 2 * C - 1;             if (c2 == 2 * C) c2 = 0;             if (r2 >= 0 && r2 < R && M[r2][c2]) Union(id(r, c), id(r2, c2));           }           for (int k = 0; k < 8; ++k) {             int r2 = r + dr[k], c2 = c + C + dc[k];             if (c2 == -1) c2 = 2 * C - 1;             if (c2 == 2 * C) c2 = 0;             if (r2 >= 0 && r2 < R && M[r2][c2]) Union(id(r, c + C), id(r2, c2));           }         }       }       printf( %d n , ans);     }     return 0;   }   