<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 {

  
    void DFS (vector<vector<int>>& grid , vector<vector<bool>>& visited , int row , int col) {
        visited[row][col] = true;
        int tempCount = 0;
        if(row - 1 >= 0 && grid[row -1 ][col]  ){
            if( !visited[row - 1][col]){
                 DFS(grid,visited, row -1 , col );}
            tempCount++;
            
        } 
        if(col - 1 >= 0 && grid[row ][col - 1] && !visited[row][col -1] ){
            if( !visited[row][col -1] )
                 DFS(grid,visited, row , col - 1 );
            tempCount++;
        }
        if(col + 1 < grid[0].size() && grid[row ][col  + 1] && !visited[row][col + 1] ){
            if( !visited[row][col + 1] )
                 DFS(grid,visited, row , col + 1);
            tempCount++;
        } 
        if(row + 1 < grid.size() && grid[row + 1][col] && !visited[row + 1][col] ){
            if(!visited[row + 1][col])
                 DFS(grid,visited, row + 1 , col );
            tempCount++;
        }  
       
    }

    int countIsland(vector<vector<int>>& grid){

        int row = grid.size();
        int col = grid[0].size();
        vector<vector<bool>> visited(row , vector<bool>(col,0) );
        int isLands = 0 ;
         for(int i = 0 ; i < row ; i++) {
            for(int j = 0 ; j < col ; j++) {
                if(grid[i][j] && !visited[i][j]) {
                    DFS(grid,visited, i , j );
                    isLands ++;
                }
            }
        }
        return isLands;
    }
public:
    int minDays(vector<vector<int>>& grid) {
        int row = grid.size();
        int col = grid[0].size();
        vector<vector<int>> count(row , vector<int>(col,0) );
        if ( countIsland(grid) > 1 ) return 0; 
        int oneCount = 0 ;
        for(int i = 0 ; i < row ; i++) {
            for(int j = 0 ; j < col ; j++) {
                if(grid[i][j]) {
                    oneCount++;
                    grid[i][j] = 0;
                    if ( countIsland(grid) > 1 ) return 1; 
                    grid[i][j] = 1;
                }
            }
        }
        if(oneCount <= 1) return oneCount;
        return 2;
    }
};
21660