Настройки поиска

#include <cstdio>
#include <memory.h>

const int maxl = 1001;

char s[maxl][maxl];
int n, m, u[maxl][maxl];
int xl, yl, xr, yr;

int dx[8] = {-1, 0, 1, 0, -1, -1, 1, 1};
int dy[8] = {0, 1, 0, -1, -1, 1, 1, -1};
int di[4] = {-1, 0, 1, 0};
int dj[4] = {0, 1, 0, -1};

void walk(int x, int y)
{
  if (x < 0 || y < 0 || x >= n || y >= m)
    return;
  if (u[x][y])
    return;
  u[x][y] = 1;
  if (x < xl && y < yl)
    xl = x, yl = y;
  if (x > xr && y > yr)
    xr = x, yr = y;
  for (int i = 0; i < 8; i++)
    walk(x + dx[i], y + dy[i]);
}

int main()
{
  scanf("%d%d", &n, &m);
  for (int i = 0; i < n; i++)
    scanf("%s", s[i]);
  
  memset(u, 0, sizeof(u));
  
  bool anychanged = true;
  
  while (anychanged) {
    for (int i = 0; i < n; i++)
      for (int j = 0; j < m; j++)
        if (s[i][j] == 'X' && !u[i][j]) {
      xl = i, xr = i;
          yl = j, yr = j;
    
      walk(i, j);
    
      for (int x = xl; x <= xr; x++)
        for (int y = yl; y <= yr; y++)
          s[y][x] = 'X', u[y][x] = 1;
        }
    
    anychanged = false;
    
    for (int i = 0; i < n; i++)
      for (int j = 0; j < m; j++)
    if (s[i][j] == '.') {
      int c = 0;
      for (int k = 0; k < 4; k++)
        if (i + di[k] >= 0 && j + dj[k] >= 0 && i + di[k] < n && j + dj[k] < m && s[i + di[k]][j + dj[k]] == 'X')
          ++c;
      if (c >= 2)
        s[i][j] = 'X', anychanged = true;
    }
  }
  
  int c = 0; 
  for (int i = 0; i < n; i++)
    for (int j = 0; j < m; j++)
      c += (s[i][j] == 'X');
      
  printf("%d\n", c);
  return 0;
}