<p>You are given an <code>m x n</code> binary grid <code>grid</code> where <code>1</code> represents land and <code>0</code> represents water. An <strong>island</strong> is a maximal <strong>4-directionally</strong> (horizontal or vertical) connected group of <code>1</code>&#39;s.</p>

<p>The grid is said to be <strong>connected</strong> if we have <strong>exactly one island</strong>, otherwise is said <strong>disconnected</strong>.</p>

<p>In one day, we are allowed to change <strong>any </strong>single land cell <code>(1)</code> into a water cell <code>(0)</code>.</p>

<p>Return <em>the minimum number of days to disconnect the grid</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/12/24/land1.jpg" style="width: 500px; height: 169px;" />
<pre>
<strong>Input:</strong> grid = [[0,1,1,0],[0,1,1,0],[0,0,0,0]]

<strong>Output:</strong> 2
<strong>Explanation:</strong> We need at least 2 days to get a disconnected grid.
Change land grid[1][1] and grid[0][2] to water and get 2 disconnected island.
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/12/24/land2.jpg" style="width: 404px; height: 85px;" />
<pre>
<strong>Input:</strong> grid = [[1,1]]
<strong>Output:</strong> 2
<strong>Explanation:</strong> Grid of full water is also disconnected ([[1,1]] -&gt; [[0,0]]), 0 islands.
</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;= 30</code></li>
	<li><code>grid[i][j]</code> is either <code>0</code> or <code>1</code>.</li>
</ul>

class Solution {
public:
    void helper(map<pair<int,int>,vector<pair<int,int>>>&adj,vector<vector<bool>>&visited,int i,int j){
        visited[i][j]=true;
        for(auto x:adj[{i,j}]){
            int ni=x.first;
            int nj=x.second;
            if(!visited[ni][nj]){
                helper(adj,visited,ni,nj);
            }
        }
        return;
    }
    int dfs(map<pair<int,int>,vector<pair<int,int>>>&adj,vector<vector<int>>& grid){
        int n=grid.size();
        int m=grid[0].size();

        vector<vector<bool>>visited(n,vector<bool>(m,false));
        int ans=0;
        for(int i=0;i<n;i++){
            for(int j=0;j<m;j++){
                if(!grid[i][j]) visited[i][j]=true;
            }
        }
        for(int i=0;i<n;i++){
            for(int j=0;j<m;j++){
                if(!visited[i][j]){
                    ans++;
                    helper(adj,visited,i,j);
                }
            }
        }
        return ans;

    }
    int minDays(vector<vector<int>>& grid) {
        map<pair<int,int>,vector<pair<int,int>>>adj;
        int n=grid.size();
        int m=grid[0].size();
        // set<pair<int,pair<int,int>>>s;
        int di[4]={0,0,-1,1};
        int dj[4]={1,-1,0,0};
        int count=0;
        for(int i=0;i<n;i++){
            for(int j=0;j<m;j++){
                if(grid[i][j]){
                    count++;
                    for(int k=0;k<4;k++){
                        int ni=i+di[k];
                        int nj=j+dj[k];
                        if(nj>=0 and nj<m and ni>=0 and ni<n and grid[ni][nj]){
                            adj[{i,j}].push_back({ni,nj});
                        }
                    }
                }
                // if(adj[{i,j}].size()) s.insert({adj[{i,j}].size(),{i,j}});
            }
        }
        int ans;
        ans=dfs(adj,grid);
        if(ans!=1) return 0;
        for(int i=0;i<n;i++){
            for(int j=0;j<m;j++){
                if(grid[i][j]){
                    grid[i][j]=0;
                    ans=dfs(adj,grid);
                    if(ans!=1) return 1;
                    grid[i][j]=1;
                }
            }
        }
        return 2;



    }
};
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