<p>You are given an <code>m x n</code> binary matrix <code>grid</code>, where <code>0</code> represents a sea cell and <code>1</code> represents a land cell.</p>

<p>A <strong>move</strong> consists of walking from one land cell to another adjacent (<strong>4-directionally</strong>) land cell or walking off the boundary of the <code>grid</code>.</p>

<p>Return <em>the number of land cells in</em> <code>grid</code> <em>for which we cannot walk off the boundary of the grid in any number of <strong>moves</strong></em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/02/18/enclaves1.jpg" style="width: 333px; height: 333px;" />
<pre>
<strong>Input:</strong> grid = [[0,0,0,0],[1,0,1,0],[0,1,1,0],[0,0,0,0]]
<strong>Output:</strong> 3
<strong>Explanation:</strong> There are three 1s that are enclosed by 0s, and one 1 that is not enclosed because its on the boundary.
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/02/18/enclaves2.jpg" style="width: 333px; height: 333px;" />
<pre>
<strong>Input:</strong> grid = [[0,1,1,0],[0,0,1,0],[0,0,1,0],[0,0,0,0]]
<strong>Output:</strong> 0
<strong>Explanation:</strong> All 1s are either on the boundary or can reach the boundary.
</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;= 500</code></li>
	<li><code>grid[i][j]</code> is either <code>0</code> or <code>1</code>.</li>
</ul>

class Solution:
    def check(self,i,j,n,m,grid):
        if i<0 or i>=n or j<0 or j>=m:
            return 
        if grid[i][j]==1:
            grid[i][j]=0
            self.check(i+1,j,n,m,grid)
            self.check(i-1,j,n,m,grid)
            self.check(i,j+1,n,m,grid)
            self.check(i,j-1,n,m,grid)
    def numEnclaves(self, grid: List[List[int]]) -> int:
        from collections import deque
        queue=deque()
        n,m=len(grid),len(grid[0])
        for i in range(n):
            for j in range(m):
                if i==0 or i==n-1 or j==0 or j==m-1:
                    if grid[i][j]==1:
                        queue.append((i,j))
        while queue:
            i,j=queue.popleft()
            self.check(i,j,n,m,grid)
        ans=0
        for i in grid:
            for j in i:
                if j==1:
                    ans+=1
        return ans
28341