<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>

#include<bits/stdc++.h>
class Solution {
public:
    void dfs(int i, int j, vector<vector<int>>& result, vector<vector<int>>& visited, int row[], int col[], int m, int n)
    {
        int rowindex, colindex;
        if(result[i][j]==0) return;
        visited[i][j]=1;
        result[i][j] = 2;

        for(int pos=0;pos<4;pos++)
        {
            rowindex = i+row[pos];
            colindex = j+col[pos];
            if( rowindex>=0 && colindex>=0 && rowindex<m && colindex<n && !visited[rowindex][colindex])
            {
                if(result[rowindex][colindex]==1)
                {
                    dfs(rowindex, colindex, result, visited, row, col, m,n);
                }
            }
        }
    }

    int numEnclaves(vector<vector<int>>& grid) {
        int m = grid.size();
        int n = grid[0].size();
        vector<vector<int>> result = grid;
        int row[] = {0,0,1,-1};
        int col[] = {1,-1,0,0};
        vector<vector<int>> visited(m, vector<int>(n,0));
        
        for(int i=0;i<m;i++) 
        {
            if(!visited[i][0])
            {
                dfs(i,0,result, visited, row,col,m,n);
            }

        }
        for(int i=0;i<n;i++) {if(!visited[0][i]) {dfs(0,i,result, visited, row,col,m,n);}}
        for(int i=0;i<m;i++) {if(!visited[i][n-1]) {dfs(i,n-1,result, visited, row,col,m,n);}}
        for(int i=0;i<n;i++) {{if(!visited[m-1][i]) dfs(m-1,i,result, visited, row,col,m,n);}}

        int res=0;
        for(int i=0;i<m;i++)
        {
        for(int j=0;j<n;j++)
        {
            cout<<result[i][j];
            if(result[i][j]==1) res++;
        }
        cout<<endl;
        }

        return res;

    }
};
40582