<p>You are given a <strong>0-indexed</strong> <code>m x n</code> binary matrix <code>land</code> where a <code>0</code> represents a hectare of forested land and a <code>1</code> represents a hectare of farmland.</p>

<p>To keep the land organized, there are designated rectangular areas of hectares that consist <strong>entirely</strong> of farmland. These rectangular areas are called <strong>groups</strong>. No two groups are adjacent, meaning farmland in one group is <strong>not</strong> four-directionally adjacent to another farmland in a different group.</p>

<p><code>land</code> can be represented by a coordinate system where the top left corner of <code>land</code> is <code>(0, 0)</code> and the bottom right corner of <code>land</code> is <code>(m-1, n-1)</code>. Find the coordinates of the top left and bottom right corner of each <strong>group</strong> of farmland. A <strong>group</strong> of farmland with a top left corner at <code>(r<sub>1</sub>, c<sub>1</sub>)</code> and a bottom right corner at <code>(r<sub>2</sub>, c<sub>2</sub>)</code> is represented by the 4-length array <code>[r<sub>1</sub>, c<sub>1</sub>, r<sub>2</sub>, c<sub>2</sub>].</code></p>

<p>Return <em>a 2D array containing the 4-length arrays described above for each <strong>group</strong> of farmland in </em><code>land</code><em>. If there are no groups of farmland, return an empty array. You may return the answer in <strong>any order</strong></em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/07/27/screenshot-2021-07-27-at-12-23-15-copy-of-diagram-drawio-diagrams-net.png" style="width: 300px; height: 300px;" />
<pre>
<strong>Input:</strong> land = [[1,0,0],[0,1,1],[0,1,1]]
<strong>Output:</strong> [[0,0,0,0],[1,1,2,2]]
<strong>Explanation:</strong>
The first group has a top left corner at land[0][0] and a bottom right corner at land[0][0].
The second group has a top left corner at land[1][1] and a bottom right corner at land[2][2].
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/07/27/screenshot-2021-07-27-at-12-30-26-copy-of-diagram-drawio-diagrams-net.png" style="width: 200px; height: 200px;" />
<pre>
<strong>Input:</strong> land = [[1,1],[1,1]]
<strong>Output:</strong> [[0,0,1,1]]
<strong>Explanation:</strong>
The first group has a top left corner at land[0][0] and a bottom right corner at land[1][1].
</pre>

<p><strong class="example">Example 3:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/07/27/screenshot-2021-07-27-at-12-32-24-copy-of-diagram-drawio-diagrams-net.png" style="width: 100px; height: 100px;" />
<pre>
<strong>Input:</strong> land = [[0]]
<strong>Output:</strong> []
<strong>Explanation:</strong>
There are no groups of farmland.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>m == land.length</code></li>
	<li><code>n == land[i].length</code></li>
	<li><code>1 &lt;= m, n &lt;= 300</code></li>
	<li><code>land</code> consists of only <code>0</code>&#39;s and <code>1</code>&#39;s.</li>
	<li>Groups of farmland are <strong>rectangular</strong> in shape.</li>
</ul>

class Solution {
public:
    int n, m;
    void f(int i, int j, int count,  vector<vector<int>>& land, vector<vector<int>>& visited, vector<vector<pair<int,int>>>& cordinates){
        if(i<0 || i>= n || j<0 || j>=m || land[i][j]==0 || visited[i][j]==1){
            return;
        }
        visited[i][j] = 1;
        cordinates[count].push_back({i,j});
        f(i+1, j , count, land, visited, cordinates);
        f(i, j+1 , count, land, visited, cordinates);
        f(i-1, j , count, land, visited, cordinates);
        f(i, j-1 , count, land, visited, cordinates);
    }
    vector<vector<int>> findFarmland(vector<vector<int>>& land) {
        n = land.size();
        m = land[0].size();
        int count = 0;
        vector<vector<int>> visited(n, vector<int>(m, 0));
        vector<vector<pair<int,int>>> cordinates(n*m);

        for(int i = 0; i< n ; i++){
            for(int j = 0; j < m ; j++){
                if(land[i][j]==1 && !visited[i][j]){
                    f(i,j, count, land, visited, cordinates);
                    count++;
                }
            }
        }

        vector<vector<int>> ans;
        for(auto itr: cordinates){
            sort(itr.begin(),itr.end());
            if(itr.size()==1){
                ans.push_back({itr[0].first,itr[0].second,itr[0].first,itr[0].second});
            }else if(itr.size()>1){
                pair<int,int> last = itr.back();
                pair<int,int> front = itr[0];
                ans.push_back({front.first, front.second, last.first,last.second});
            }
        }
        return ans;
    }
};
124026