<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 {
public:
    void dfs(int row, int col, vector<vector<int>>& grid, int m, int n, vector<vector<bool>>& visited, int& temp){
        visited[row][col] = 1;
        temp++;
        vector<pair<int, int>> directions = {{1,0},{-1,0},{0,1},{0,-1}};
        for(auto dir: directions){
            int nrow = row+dir.first;
            int ncol = col+dir.second;
            if(nrow>=0 && nrow<m && ncol>=0 && ncol<n && !visited[nrow][ncol] && grid[nrow][ncol]==1){
                dfs(nrow, ncol, grid, m, n, visited, temp);
            }
        }
    }
    int maxAreaOfIsland(vector<vector<int>>& grid) {
        int area = 0;
        int m = grid.size();
        int n = grid[0].size();
        vector<vector<bool>> visited(m, vector<bool>(n,false));
        for(int i=0; i<m; i++){
            for(int j=0; j<n; j++){
                if(!visited[i][j] && grid[i][j]==1){
                    int temp = 0;
                    dfs(i, j, grid, m, n, visited, temp);
                    area = max(area, temp);
                }
            }
        }
        return area;
    }
};
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