<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 solve(vector<vector<int>>&grid,int n,int x,int y,map<pair<int,int>,bool>&vis){
    queue<pair<int,int>>q;
    q.push({x,y});
    vis[{x,y}]= true;
    int ans =0;
  int dx[4]={1,0,-1,0};
    int dy[4]={0,-1,0,1};

    while(!q.empty()){
        auto fnode= q.front();
        int nx= fnode.first;
        int ny= fnode.second;
        q.pop();
        ans++;
      
        for(int i=0;i<4;i++){
            int newx= nx+dx[i];
            int newy= ny+dy[i];

            if(newx>=0 && newx<n && newy>=0 && newy<grid[0].size() && !vis[{newx,newy}] && grid[newx][newy]==1){
                    q.push({newx,newy});
                    vis[{newx,newy}]= true;
            }
        }
    }
    return ans;
    
}
    int maxAreaOfIsland(vector<vector<int>>& grid) {
        int n= grid.size();
        int maxi = 0;
        map<pair<int,int>,bool>vis;
        for(int i=0;i<n;i++){
            for(int j=0;j<grid[0].size();j++){
                if(grid[i][j]==1 && !vis[{i,j}]){
                    int ans = solve(grid,n,i,j,vis);
                    maxi = max(maxi,ans);
                }
            }
        }
        return maxi;
    }
};
36470