<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 maxArea = 0;
        for(int i=0; i<grid.size(); i++){
            for(int j=0; j<grid[0].size(); j++){
                if(grid[i][j]){
                    grid[i][j] = 0;
                    maxArea = max(findArea(grid, i, j), maxArea);
                }
            }
        }
        return maxArea;
    }
    int findArea(vector<vector<int>>& grid, int curRow, int curCol){
        stack<pair<int, int>> st;
        st.push({curRow, curCol});
        int area = 0;
        while(!st.empty()){
            pair<int, int> curLocation = st.top();
            st.pop();
            area++;
            grid[curLocation.first][curLocation.second] = 0;
            if(validCoordinate(curLocation.first-1, curLocation.second, grid)){
                st.push({curLocation.first-1, curLocation.second});
            }
            if(validCoordinate(curLocation.first+1, curLocation.second, grid)){
                st.push({curLocation.first+1, curLocation.second});
            }
            if(validCoordinate(curLocation.first, curLocation.second-1, grid)){
                st.push({curLocation.first, curLocation.second-1});
            }
            if(validCoordinate(curLocation.first, curLocation.second+1, grid)){
                st.push({curLocation.first, curLocation.second+1});
            }
        }
        return area;
    }
    bool validCoordinate(int row, int col, vector<vector<int>>& grid){
        if(row >= 0 && row < grid.size() && col >= 0 && col < grid[0].size() && grid[row][col] == 1){
            grid[row][col] = 0;
            return true;
        }
        return false;
    }
};
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