<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 disintegrateIsland(vector<vector<int>>& grid, int row, int col) {
        int rows = grid.size();
        int cols = grid[0].size();

        if (col >= cols || col < 0 || row >= rows || row < 0 || grid[row][col] != 1) return;
        

        grid[row][col] = -1;
        disintegrateIsland(grid, row, col + 1);
        disintegrateIsland(grid, row, col - 1);
        disintegrateIsland(grid, row + 1, col);
        disintegrateIsland(grid, row - 1, col);
    }

    int islandCount(vector<vector<int>>& grid) {
        int rows = grid.size();
        int cols = grid[0].size();

        int count = 0;
        for (int row = 0; row < rows; row++) {
            for (int col = 0; col < cols; col++) {
                if (grid[row][col] == 1) {
                    count++;
                    disintegrateIsland(grid, row, col);
                }
            }
        }
        for (int row = 0; row < rows; row++) {
            for (int col = 0; col < cols; col++) {
                if (grid[row][col] == -1) {
                    grid[row][col] = 1;
                }
            }
        }
        return count;
    }
    int minDays(vector<vector<int>>& grid) {
        int islands = islandCount(grid);
        if (islands != 1) return 0;

        int rows = grid.size();
        int cols = grid[0].size();

        for (int row = 0; row < rows; row++) {
            for (int col = 0; col < cols; col++) {
                if (grid[row][col] == 1) {
                    grid[row][col] = 0;

                    if (islandCount(grid) != 1) return 1;

                    grid[row][col] = 1;
                }
            }
        }
        
        return 2;
    }
};
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