<p>You are given an <code>m x n</code> binary matrix <code>grid</code>. An island is a group of <code>1</code>&#39;s (representing land) connected <strong>4-directionally</strong> (horizontal or vertical.) You may assume all four edges of the grid are surrounded by water.</p>

<p>The <strong>area</strong> of an island is the number of cells with a value <code>1</code> in the island.</p>

<p>Return <em>the maximum <strong>area</strong> of an island in </em><code>grid</code>. If there is no island, return <code>0</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/05/01/maxarea1-grid.jpg" style="width: 500px; height: 310px;" />
<pre>
<strong>Input:</strong> grid = [[0,0,1,0,0,0,0,1,0,0,0,0,0],[0,0,0,0,0,0,0,1,1,1,0,0,0],[0,1,1,0,1,0,0,0,0,0,0,0,0],[0,1,0,0,1,1,0,0,1,0,1,0,0],[0,1,0,0,1,1,0,0,1,1,1,0,0],[0,0,0,0,0,0,0,0,0,0,1,0,0],[0,0,0,0,0,0,0,1,1,1,0,0,0],[0,0,0,0,0,0,0,1,1,0,0,0,0]]
<strong>Output:</strong> 6
<strong>Explanation:</strong> The answer is not 11, because the island must be connected 4-directionally.
</pre>

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

<pre>
<strong>Input:</strong> grid = [[0,0,0,0,0,0,0,0]]
<strong>Output:</strong> 0
</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;= 50</code></li>
	<li><code>grid[i][j]</code> is either <code>0</code> or <code>1</code>.</li>
</ul>

class Solution {
    private:
    int maxIslandArea(int row, int col, int n ,int m,vector<vector<int>>&grid,vector<vector<int>>&vis){
     vis[row][col] = 1;

        int delrow[] = {-1,1,0,0};
        int delcol[] = {0,0,1,-1};
        int maxi = 0;

        for(int i =0;i<4;i++){
        int nrow = row+delrow[i];
        int ncol = col+delcol[i];
        

        if(nrow >=0 && nrow < n && ncol >= 0 && ncol < m && !vis[nrow][ncol] && grid[nrow][ncol]){
            maxi += maxIslandArea(nrow,ncol,n,m,grid,vis);
        }
        }
        return maxi+1;
    }

public:
    int maxAreaOfIsland(vector<vector<int>>& grid) {
        int n = grid.size();
        int m = grid[0].size();
        int max_area = 0;
        vector<vector<int>>vis(n,vector<int>(m,0));

        for(int row = 0;row < n;row++){
            for(int col =0;col<m;col++){
            if(grid[row][col] !=0){
                max_area = max(max_area,maxIslandArea(row,col,n,m,grid,vis));
                }
            }
        }
    return max_area;
    }
};
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