<p>Given a 2D&nbsp;<code>grid</code> consists of <code>0s</code> (land)&nbsp;and <code>1s</code> (water).&nbsp; An <em>island</em> is a maximal 4-directionally connected group of <code><font face="monospace">0</font>s</code> and a <em>closed island</em>&nbsp;is an island <strong>totally</strong>&nbsp;(all left, top, right, bottom) surrounded by <code>1s.</code></p>

<p>Return the number of <em>closed islands</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<p><img alt="" src="https://assets.leetcode.com/uploads/2019/10/31/sample_3_1610.png" style="width: 240px; height: 120px;" /></p>

<pre>
<strong>Input:</strong> grid = [[1,1,1,1,1,1,1,0],[1,0,0,0,0,1,1,0],[1,0,1,0,1,1,1,0],[1,0,0,0,0,1,0,1],[1,1,1,1,1,1,1,0]]
<strong>Output:</strong> 2
<strong>Explanation:</strong> 
Islands in gray are closed because they are completely surrounded by water (group of 1s).</pre>

<p><strong class="example">Example 2:</strong></p>

<p><img alt="" src="https://assets.leetcode.com/uploads/2019/10/31/sample_4_1610.png" style="width: 160px; height: 80px;" /></p>

<pre>
<strong>Input:</strong> grid = [[0,0,1,0,0],[0,1,0,1,0],[0,1,1,1,0]]
<strong>Output:</strong> 1
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> grid = [[1,1,1,1,1,1,1],
&nbsp;              [1,0,0,0,0,0,1],
&nbsp;              [1,0,1,1,1,0,1],
&nbsp;              [1,0,1,0,1,0,1],
&nbsp;              [1,0,1,1,1,0,1],
&nbsp;              [1,0,0,0,0,0,1],
               [1,1,1,1,1,1,1]]
<strong>Output:</strong> 2
</pre>

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

<ul>
	<li><code>1 &lt;= grid.length, grid[0].length &lt;= 100</code></li>
	<li><code>0 &lt;= grid[i][j] &lt;=1</code></li>
</ul>

class Solution:
    def closedIsland(self, grid: List[List[int]]) -> int:
        visited = set()
        ans = 0
        directions = [(0,1),(1,0),(-1,0),(0,-1)]
        def bfs(r, c):
            queue = deque([(r,c)])
            visited.add((r,c))

            while queue:
                row, col = queue.popleft()

                for dy, dx in directions:
                    n_row, n_col = row + dy, col + dx
                    
                    if 0 <= n_row < len(grid) and 0 <= n_col < len(grid[0]) and grid[n_row][n_col] == 0 and (n_row, n_col) not in visited:
                        visited.add((n_row, n_col))
                        queue.append((n_row, n_col))

        for row in range(len(grid)):
            for col in range(len(grid[0])):
                if row == 0 or row == len(grid) - 1 or col == 0 or col == len(grid[0]) - 1:
                    if grid[row][col] == 0:
                        bfs(row, col)

        for row in range(len(grid)):
            for col in range(len(grid[0])):
                if (row, col) not in visited and grid[row][col] == 0:
                    # visited.add((row,col))
                    bfs(row, col)
                    ans += 1

        return ans

        
                    
17700