<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:
    int bfs(int row, int col, vector<vector<int>>& vis, vector<vector<int>>& grid){
        int n= grid.size();
        int m= grid[0].size();
        int count=1;

        vis[row][col]=1;

        queue<pair<int,int>> q;
        q.push({row,col});

        vector<int> delrow={-1,0,1,0};
        vector<int> delcol={0,1,0,-1};

        while(!q.empty()){
            int Row= q.front().first;
            int Col= q.front().second;
            q.pop();

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

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

    int maxAreaOfIsland(vector<vector<int>>& grid) {
        int n= grid.size();
        int m= grid[0].size();

        vector<vector<int>> vis(n, vector<int>(m,0));
        int cnt=0;

        for(int i=0; i<n; i++){
            for(int j=0; j<m; j++){
                if(grid[i][j]==1 && !vis[i][j]){
                    
                    cnt= max(cnt,bfs(i,j,vis,grid));
                }
            }
        }
        return cnt;
    }
};
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