<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>

queue<pair<int, int>> q;
class Solution {
public:
    int n, m;
    int dir[4][2] = {{-1, 0},{1, 0},{0, -1},{0, 1}};

    bool isValid(int i, int j, vector<vector<int>>& temp){
        return i >= 0 && i < n && j >= 0 && j < m && temp[i][j];
    }

    void bfs(queue<pair<int, int>> &q, vector<vector<int>>& grid){
        pair<int, int> pr;
        int i, j;
        while(q.size()){
            i = q.front().first;
            j = q.front().second;
            for(auto &it: dir){
                if(isValid(i + it[0], j + it[1], grid)){
                    q.push({i + it[0], j + it[1]});
                    grid[i + it[0]][j + it[1]] = 0;
                }
            }
            q.pop();
        }
    }

    int countNumberOfIsland(vector<vector<int>> &grid){
        int i = 0, j;
        int cnt = 0;
        while(i < n){
            j = 0;
            while(j < m){
                if(grid[i][j]){
                    cnt += 1;
                    q.push({i, j});
                    grid[i][j] = 0;
                    bfs(q, grid);
                }
                j += 1;
            }
            i += 1;
        } 
        return cnt;
    }

    int makeCopy(vector<vector<int>> grid){
        return countNumberOfIsland(grid);
    }

    bool isDevidedIntoTwo(int i, int j, vector<vector<int>> grid){
        grid[i][j] = 0;
        return countNumberOfIsland(grid) - 1;
    }

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

        ios::sync_with_stdio(false);
        cin.tie(0);
        cout.tie(0);

        n = grid.size();
        m = grid[0].size();

        int temp = makeCopy(grid);
        if(temp == 0 || temp >= 2) return 0;

        int i = 0, j;
        while(i < n){
            j = 0;
            while(j < m){
                if(grid[i][j] && isDevidedIntoTwo(i, j, grid)) return 1;
                j += 1;
            }
            i += 1;
        }

        return 2;
    }

};
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