In a N x N grid composed of 1 x 1 squares, each 1 x 1 square consists of a /, \, or blank space.  These characters divide the square into contiguous regions.
(Note that backslash characters are escaped, so a \ is represented as "\\".)
Return the number of regions.
 













Example 1:
Input:
[
  " /",
  "/ "
]
Output: 2
Explanation: The 2x2 grid is as follows:



Example 2:
Input:
[
  " /",
  "  "
]
Output: 1
Explanation: The 2x2 grid is as follows:



Example 3:
Input:
[
  "\\/",
  "/\\"
]
Output: 4
Explanation: (Recall that because \ characters are escaped, "\\/" refers to \/, and "/\\" refers to /\.)
The 2x2 grid is as follows:



Example 4:
Input:
[
  "/\\",
  "\\/"
]
Output: 5
Explanation: (Recall that because \ characters are escaped, "/\\" refers to /\, and "\\/" refers to \/.)
The 2x2 grid is as follows:



Example 5:
Input:
[
  "//",
  "/ "
]
Output: 3
Explanation: The 2x2 grid is as follows:


 
Note:

1 <= grid.length == grid[0].length <= 30
grid[i][j] is either '/', '\', or ' '.

```python

USER_FILENAME = "<user_code>"
import sys, json, builtins
import math, heapq, bisect, itertools, functools, collections, statistics, fractions, decimal, operator, array, random, re, string, os, pathlib
try:
    import resource as _res
except Exception:
    _res = None
from collections import Counter, defaultdict, deque, OrderedDict
from functools import lru_cache, reduce
from itertools import accumulate, permutations, combinations, product
from math import gcd, ceil, floor, sqrt
from decimal import Decimal
try:
    from typing import *
except Exception:
    pass
try:
    sys.setrecursionlimit(1_000_000)
except Exception:
    pass
try:
    import site as _site
    try:
        _sys_sites = _site.getsitepackages() if hasattr(_site, "getsitepackages") else []
        for _p in _sys_sites:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
    try:
        _usp = _site.getusersitepackages()
        if isinstance(_usp, str):
            _usp = [_usp]
        for _p in _usp:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
except Exception:
    pass

def _disabled_input(*args, **kwargs):
    raise RuntimeError("input() is disabled in callable mode")
builtins.input = _disabled_input

ns = {"__name__": "__judge__"}  # prevent if __name__ == "__main__" blocks
for _k, _v in list(globals().items()):
    if not _k.startswith("_"):
        ns[_k] = _v
_CODE = "#\n# *-------*\n# | \\\\ 0 / |\n# | 3 * 1 |\n# | / 2 \\\\ |\n# *-------*\nclass DSU:\n    def __init__(self, N):\n        self.pres = list(range(N))  #   初始，每个节点指向自己\n    def setRoot(self, i, root):\n        while self.pres[i] != root:\n            t = self.pres[i]\n            self.pres[i] = root\n            i = t\n        return \n    def findRoot(self, i):\n        root = i\n        while root != self.pres[root]:\n            root = self.pres[root]\n        self.setRoot(i, root)\n        return root\n    def merge(self, i, j):\n        root = self.findRoot(i)\n        self.setRoot(j, root)\n    \n    \nclass Solution:\n    def regionsBySlashes(self, grid: List[str]) -> int:\n        def getPos(N, h, w, i):\n            return N*4 * h + 4*w + i\n\n        #   借鉴三角面片思路\n        N = len(grid)\n        NN4 = N*N*4\n        dsu = DSU(NN4)\n        \n        #   合并临近矩形\n        for h in range(N):\n            for w in range(N):\n                p  = getPos(N, h, w, 0)\n                pR = getPos(N, h, w+1, 0)\n                pD = getPos(N, h+1, w, 0)                \n                pRD= getPos(N, h+1, w+1, 0)\n                if h < N-1:\n                    dsu.merge(p+2, pD+0)\n                if w < N-1:\n                    dsu.merge(p+1, pR+3)\n                \n\n        #   检查输入网格\n        for h in range(N):\n            for w in range(N):\n                p  = getPos(N, h, w, 0)\n                if grid[h][w] == '/':\n                    dsu.merge(p+0, p+3)\n                    dsu.merge(p+1, p+2)\n                elif grid[h][w] == '\\\\\\\\':\n                    dsu.merge(p+0, p+1)\n                    dsu.merge(p+2, p+3)\n                else:\n                    dsu.merge(p+0, p+1)\n                    dsu.merge(p+0, p+2)\n                    dsu.merge(p+0, p+3)\n        \n        return sum(dsu.findRoot(x) == x for x in range(NN4))\n\n"
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'regionsBySlashes'
if _fn_name:
    if "Solution" in ns:
        try:
            _obj = ns["Solution"]()
            if hasattr(_obj, _fn_name):
                _target = getattr(_obj, _fn_name)
        except Exception:
            _target = None
    if _target is None and _fn_name in ns and callable(ns[_fn_name]):
        _target = ns[_fn_name]
# Fallback: if there's exactly one user-defined function, use it
if _target is None:
    _cands = [v for k, v in ns.items() if callable(v) and getattr(v, "__module__", "") in ("__judge__", "__main__")]
    _user_funcs = [c for c in _cands if getattr(c, "__name__", "").startswith("_") is False]
    if len(_user_funcs) == 1:
        _target = _user_funcs[0]
if _target is None:
    raise RuntimeError(f"Could not resolve callable '{_fn_name}'")

_raw = sys.stdin.read().strip()
if _raw:
    _parsed = json.loads(_raw)
    if isinstance(_parsed, dict):
        _kwargs = _parsed.get("kwargs", {})
        _args = _parsed.get("args", [])
    else:
        _args, _kwargs = _parsed, {}
else:
    _args, _kwargs = [], {}
if not isinstance(_args, (list, tuple)):
    _args = [_args]
_res = _target(*_args, **_kwargs)
try:
    sys.stdout.write(repr(_res) + "\n")
except Exception:
    pass

```

Measured memory_bytes: 8124