Problem - 377A - Codeforces

maze.c

#include <stdio.h>
#include <stdlib.h>

void fillAfter (char **, int, int, int *);

int dx[4] = {-1, 0, 1, 0};
int dy[4] = {0, -1, 0, 1};
int n, m;

int
main (int argc, char **argv)
{
  int k, f;
  int i, j;
  int x, y;
  int left;
  char **grid;

  f = 0;

  fscanf (stdin, "%d %d %d ", &n, &m, &k);
  grid = malloc (sizeof *grid * n);
  for (i = 0; i < n; i++)
    {
      grid[i] = malloc (sizeof **grid * (m + 2));
      fgets (grid[i], m + 2, stdin);
      for (j = 0; j < m; j++)
        {
          if (grid[i][j] == '.')
            {
              f += 1;
              x = i;
              y = j;
            }
        }
    }

  left = f - k;
  fillAfter (grid, x, y, &left);

  for (i = 0; i < n; i++)
    {
      for (j = 0; j < m; j++)
        {
          if (grid[i][j] == 'V')
            {
              grid[i][j] = '.';
            }
        }
      grid[i][m] = '\0';
      fprintf (stdout, "%s\n", grid[i]);
      free (grid[i]);
    }
  free (grid);
  return EXIT_SUCCESS;
}

void fillAfter (char **grid, int cx, int cy, int *left)
{
  char *temp;
  int i,j;

  if (cx < 0 || cx >= n || cy < 0 || cy >= m)
    return;

  temp = &grid[cx][cy];

  if (*temp == '.')
    {
      *temp = (*left)-- > 0 ? 'V' : 'X';

      for (i = 0; i < 4; i++)
        {
          for (j = 0; j < 4; j++)
            {
              fillAfter (grid, cx + dx[i], cy + dy[i], left);
            }
        }
    }
}