1992. Find All Groups of Farmland.cpp

class Solution {
public:
    int m, n;
    vector<vector<int>> result;
    vector<vector<int>> directions{{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
    void dfs(vector<vector<int>>& land, int i, int j, int& r2, int& c2) {
        land[i][j] = 0;
        r2 = max(r2, i);
        c2 = max(c2, j);
        for (auto& dir : directions) {
            int new_i = i + dir[0];
            int new_j = j + dir[1];
            if (new_i >= 0 && new_i < m && new_j >= 0 && new_j < n &&
                land[new_i][new_j] == 1) {
                dfs(land, new_i, new_j, r2, c2);
            }
        }
    }

    vector<vector<int>> findFarmland(vector<vector<int>>& land) {
        m = land.size();
        n = land[0].size();
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                if (land[i][j] == 1) {
                    int r1 = i;
                    int c1 = j;
                    int r2 = -1;
                    int c2 = -1;
                    dfs(land, i, j, r2, c2);
                    result.push_back({r1, c1, r2, c2});
                }
            }
        }
        return result;
    }
};