c maze gen

maze.c

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

typedef struct
{
  int x, y;
} Vector2d;

#define WALL "#"
#define SPACE " "

void printMaze(int mazeSize, int **sides, int **topAndBots)
{
  int y, x;
  for (y = 0; y <= mazeSize * 2; y++)
  {
    for (x = 0; x <= mazeSize * 2; x++)
      if (y % 2 == 0 && x % 2 == 0)
        printf(WALL);
      else if (y % 2 == 0)
        if (topAndBots[y / 2][x / 2])
          printf(SPACE);
        else
          printf(WALL);
      else if (x % 2 == 0)
        if (sides[y / 2][x / 2])
          printf(SPACE);
        else
          printf(WALL);
      else
        printf(SPACE);
    putchar('\n');
  }
}

int main(int argc, char **argv)
{
  srand((unsigned int)time(NULL));

  int mazeSize = argc > 1 ? atoi(argv[1]) : 10;
  /* TODO: handle invalid input */

  int **sides = (int **)calloc(mazeSize, sizeof(int *));
  int **topAndBots = (int **)calloc(mazeSize + 1, sizeof(int *));
  int **visited = (int **)calloc(mazeSize, sizeof(int *));

  int i;
  for (i = 0; i < mazeSize; i++)
  {
    sides[i] = (int *)calloc(mazeSize + 1, sizeof(int));
    topAndBots[i] = (int *)calloc(mazeSize, sizeof(int));
    visited[i] = (int *)calloc(mazeSize, sizeof(int));
  }
  topAndBots[mazeSize] = (int *)calloc(mazeSize, sizeof(int));
  Vector2d *toVisitStack = (Vector2d *)calloc(mazeSize * mazeSize, sizeof(Vector2d));
  /* TODO: check callocs success */

  long toVisitLast = 0;
  toVisitStack[0] = (Vector2d){0, 0};
  visited[0][0] = 1;

  const Vector2d dirs[4] = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
  while (toVisitLast >= 0)
  {
    Vector2d cur = toVisitStack[toVisitLast];
    int visitable = 0;
    Vector2d visitableDirs[4];
    for (i = 0; i < 4; i++)
    {
      Vector2d dir = dirs[i];
      Vector2d next = {cur.x + dir.x, cur.y + dir.y};
      if (next.x < 0 || next.x >= mazeSize || next.y < 0 || next.y >= mazeSize)
        continue;
      if (visited[next.y][next.x])
        continue;
      visitableDirs[visitable++] = dir;
    }

    if (!visitable)
    {
      toVisitLast--;
      continue;
    }

    Vector2d nextDir = visitableDirs[rand() % visitable];
    Vector2d next = {cur.x + nextDir.x, cur.y + nextDir.y};
    visited[next.y][next.x] = 1;
    toVisitStack[++toVisitLast] = next;

    if (nextDir.x == 0 && nextDir.y == 1)
      topAndBots[next.y][next.x] = 1;
    else if (nextDir.x == 1 && nextDir.y == 0)
      sides[next.y][next.x] = 1;
    else if (nextDir.x == 0 && nextDir.y == -1)
      topAndBots[cur.y][cur.x] = 1;
    else if (nextDir.x == -1 && nextDir.y == 0)
      sides[cur.y][cur.x] = 1;
  }

  // printMaze(mazeSize, sides, topAndBots);

  /* TODO: free all memory */
  return 0;
}