<p>You are given an <code>m x n</code> binary grid <code>grid</code> where <code>1</code> represents land and <code>0</code> represents water. An <strong>island</strong> is a maximal <strong>4-directionally</strong> (horizontal or vertical) connected group of <code>1</code>&#39;s.</p>

<p>The grid is said to be <strong>connected</strong> if we have <strong>exactly one island</strong>, otherwise is said <strong>disconnected</strong>.</p>

<p>In one day, we are allowed to change <strong>any </strong>single land cell <code>(1)</code> into a water cell <code>(0)</code>.</p>

<p>Return <em>the minimum number of days to disconnect the grid</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/12/24/land1.jpg" style="width: 500px; height: 169px;" />
<pre>
<strong>Input:</strong> grid = [[0,1,1,0],[0,1,1,0],[0,0,0,0]]

<strong>Output:</strong> 2
<strong>Explanation:</strong> We need at least 2 days to get a disconnected grid.
Change land grid[1][1] and grid[0][2] to water and get 2 disconnected island.
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/12/24/land2.jpg" style="width: 404px; height: 85px;" />
<pre>
<strong>Input:</strong> grid = [[1,1]]
<strong>Output:</strong> 2
<strong>Explanation:</strong> Grid of full water is also disconnected ([[1,1]] -&gt; [[0,0]]), 0 islands.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>m == grid.length</code></li>
	<li><code>n == grid[i].length</code></li>
	<li><code>1 &lt;= m, n &lt;= 30</code></li>
	<li><code>grid[i][j]</code> is either <code>0</code> or <code>1</code>.</li>
</ul>

class Solution:
    def minDays(self, grid: List[List[int]]) -> int:
        ROWS, COLS = len(grid), len(grid[0])
        ones_pos = [(i, j) for i in range(ROWS) for j in range(COLS) if grid[i][j] == 1]
        def numIslands(grid, ones_pos) -> int:
            islands = 0
            visited = set()
            def bfs(grid, pos, visited):
                r, c = pos
                q = deque([(r, c)])

                dirs = [(0, 1), (1, 0), (-1, 0), (0, -1)]
                while q:
                    r, c = q.popleft()
                    for dr, dc in dirs:
                        nr, nc = r+dr, c+dc
                        if 0 <= nr < ROWS and 0 <= nc < COLS and grid[nr][nc] == 1 and (nr, nc) not in visited:
                            visited.add((nr, nc))
                            q.append((nr, nc))
            for pos in ones_pos:
                if pos in visited:
                    continue
                else:
                    bfs(grid, pos, visited)
                    islands += 1
            return islands
        # 0 changes
        init_islands = numIslands(grid, ones_pos)
        if init_islands > 1 or init_islands == 0:
            return 0
        # 1 change
        for pos in ones_pos:
            r, c = pos
            new_grid = deepcopy(grid)
            new_grid[r][c] = 0
            new_ones = ones_pos.copy()
            new_ones.remove((r, c))
            new_islands = numIslands(new_grid, new_ones)
            print(grid, new_grid, new_ones)
            if new_islands > 1 or new_islands == 0:
                return 1
        return 2
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