<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 maxAreaOfIsland(vector<vector<int>>& grid) {
        int ans = 0;
        int rows = grid.size();
        int cols = grid[0].size();
        for(int i = 0; i < rows; i++)
            for(int j = 0; j < cols; j++)
                if(grid[i][j] == 1)
                    ans = max(ans, bfs(i, j, rows, cols, grid));
        return ans;
    }
private:
    int bfs(int r, int c, int rows, int cols, vector<vector<int>>& grid){
        int area = 1;
        int directions[4][2] = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
        queue<pair<int, int>> q;
        q.push({r, c});
        grid[r][c] = 0;
        while(!q.empty()){
            auto [x, y] = q.front();
            q.pop();
            for(auto &[i, j]: directions){
                if(0 <= x + i && x + i < rows && 0 <= y + j && y + j < cols && grid[x + i][y + j] == 1){
                    grid[x + i][y + j] = 0;
                    q.push({x + i, y + j});
                    area++;
                }
            }
        }
        return area;
    }
};
31010