<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 {
public:
void dfs(int row,int col,vector<vector<int>>& grid,vector<vector<int>>&visited){
    visited[row][col]=1;
    vector<pair<int,int>>direction{{-1,0},{1,0},{0,-1},{0,1}};
    for(auto [x,y] : direction){
        int nx=x+row;
        int ny=y+col;
        if(nx>=0 && ny>=0 && ny<grid[0].size() && nx<grid.size() && grid[nx][ny]==1){
            if(!visited[nx][ny]){
                dfs(nx,ny,grid,visited);
            }
        }
    }
}
    int numEnclaves(vector<vector<int>>& grid) {
        int row=grid.size();
        int col=grid[0].size();
        vector<vector<int>>visited(row,vector<int>(col,0));

        for(int i=0;i<row;i++){
            for(int j=0;j<col;j++){
                if(i==0 || j==0 || i==row-1|| j==col-1){

                if(grid[i][j]==1&&!visited[i][j]){
                    dfs(i,j,grid,visited);
                }
                }
            }
        }
int cnt=0;
        for(int i=0;i<row;i++){
            for(int j=0;j<col;j++){
                if(grid[i][j]==1 && visited[i][j]!=1){
                    cnt++;
                }
            }
        }
        return cnt;
    }
};
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