1using System;
2using System.Collections.Generic;
3
4public class Solution {
5    public int[][] FindFarmland(int[][] land) {
6        int m = land.Length;
7        int n = land[0].Length;
8        bool[,] visited = new bool[m, n];
9        var results = new List<int[]>();
10
11        for (int i = 0; i < m; i++) {
12            for (int j = 0; j < n; j++) {
13                if (land[i][j] == 1 && !visited[i, j]) {
14                    int maxRow = i, maxCol = j;
15                    var queue = new Queue<(int, int)>();
16                    queue.Enqueue((i, j));
17                    visited[i, j] = true;
18
19                    while (queue.Count > 0) {
20                        var (row, col) = queue.Dequeue();
21                        maxRow = Math.Max(maxRow, row);
22                        maxCol = Math.Max(maxCol, col);
23
24                        int[,] directions = { {0, 1}, {1, 0} };
25                        for (int d = 0; d < directions.GetLength(0); d++) {
26                            int newRow = row + directions[d, 0], newCol = col + directions[d, 1];
27                            if (newRow < m && newCol < n && land[newRow][newCol] == 1 && !visited[newRow, newCol]) {
28                                visited[newRow, newCol] = true;
29                                queue.Enqueue((newRow, newCol));
30                            }
31                        }
32                    }
33                    results.Add(new int[] { i, j, maxRow, maxCol });
34                }
35            }
36        }
37        return results.ToArray();
38    }
39}

#include <unordered_map>
using namespace std;

class Solution {
public:
    vector<int> parent, rank;

    int find(int x) {
        if (parent[x] != x) {
            parent[x] = find(parent[x]);
        }
        return parent[x];
    }

    void unionSets(int x, int y) {
        int rootX = find(x);
        int rootY = find(y);
        if (rootX != rootY) {
            if (rank[rootX] > rank[rootY]) {
                parent[rootY] = rootX;
            } else if (rank[rootX] < rank[rootY]) {
                parent[rootX] = rootY;
            } else {
                parent[rootY] = rootX;
                rank[rootX]++;
            }
        }
    }

    vector<vector<int>> findFarmland(vector<vector<int>>& land) {
        int m = land.size();
        int n = land[0].size();
        parent.resize(m * n);
        rank.resize(m * n, 0);

        for (int i = 0; i < m; ++i) {
            for (int j = 0; j < n; ++j) {
                if (land[i][j] == 1) {
                    int index = i * n + j;
                    parent[index] = index;
                    if (i > 0 && land[i-1][j] == 1) {
                        unionSets(index, (i-1) * n + j);
                    }
                    if (j > 0 && land[i][j-1] == 1) {
                        unionSets(index, i * n + (j-1));
                    }
                }
            }
        }

        unordered_map<int, vector<int>> bounds;
        for (int i = 0; i < m; ++i) {
            for (int j = 0; j < n; ++j) {
                if (land[i][j] == 1) {
                    int root = find(i * n + j);
                    if (!bounds.count(root)) {
                        bounds[root] = {i, j, i, j};
                    } else {
                        bounds[root][0] = min(bounds[root][0], i);
                        bounds[root][1] = min(bounds[root][1], j);
                        bounds[root][2] = max(bounds[root][2], i);
                        bounds[root][3] = max(bounds[root][3], j);
                    }
                }
            }
        }

        vector<vector<int>> results;
        for (auto& bound : bounds) {
            results.push_back(bound.second);
        }

        return results;
    }
};