Python readable DFS on upscaled grid
Explanation:\n\n\nTransform every \'/\' or \'\\\' into an upscaled 1:3 grid. I set the slash boundaries to "False" and the open regions to "True". Then, I used 
**Explanation:**\n![image](https://assets.leetcode.com/users/albertzhong/image_1566784257.png)\n\nTransform every \'/\' or \'\\\\\' into an upscaled 1:3 grid. I set the slash boundaries to "False" and the open regions to "True". Then, I used a DFS algorithm to traverse through the entire big grid. Every time the algorithm comes across a "True" that hasn\'t been seen yet, it will iteratively add all neighboring "Trues" to the "seen" set. \n\n```\n        n = len(grid) * 3\n        big_grid = [[True for j in range(n)] for i in range(n)]\n        \n        for i, row in enumerate(grid):\n            for j, char in enumerate(row):\n                if char == \'/\':\n                    big_grid[3 * i][(3 * j) + 2] = False\n                    big_grid[(3 * i) + 1][(3 * j) + 1] = False\n                    big_grid[(3 * i) + 2][3 * j] = False\n                elif char == \'\\\\\':\n                    big_grid[3 * i][3 * j] = False\n                    big_grid[(3 * i) + 1][(3 * j) + 1] = False\n                    big_grid[(3 * i) + 2][(3 * j) + 2] = False\n                \n        seen = set()\n        regions_count = 0\n        \n        for i, row in enumerate(big_grid):\n            for j, is_char in enumerate(row):\n                if is_char and (i, j) not in seen:\n                    regions_count += 1\n                    stack = [(i, j)]\n                    while stack:\n                        a, b = stack.pop()\n                        seen.add((a, b))\n                        if a > 0 and big_grid[a - 1][b] and (a - 1, b) not in seen:\n                            stack.append((a - 1, b))\n                        if a < n - 1 and big_grid[a + 1][b] and (a + 1, b) not in seen:\n                            stack.append((a + 1, b))\n                        if b > 0 and big_grid[a][b - 1] and (a, b - 1) not in seen:\n                            stack.append((a, b - 1))\n                        if b < n - 1 and big_grid[a][b + 1] and (a, b + 1) not in seen:\n                            stack.append((a, b + 1))\n                \n        return regions_count\n```
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