func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long INF = 1e9 + 7;   const int N = 4e5 + 10;   vector<int> ans[N];   vector<int> v[N];   int tot;   int vis[N];   int cnt = 0;   void dfs(int x) {     vis[x] = 1;     ans[cnt++ / tot].push_back(x);     for (auto &y : v[x]) {       if (vis[y]) continue;       dfs(y);       ans[cnt++ / tot].push_back(x);     }   }   int main() {     int n, m, k;     cin >> n >> m >> k;     tot = (2 * n + k - 1) / k;     while (m--) {       int x, y;       cin >> x >> y;       v[x].push_back(y);       v[y].push_back(x);     }     for (int i = 1; i <= n; i++) {       if (vis[i]) continue;       cnt = (cnt + tot - 1) / tot * tot;       dfs(i);     }     for (int i = 0; i < k; i++) {       if (ans[i].empty()) ans[i].push_back(1);       printf( %d , ans[i].size());       for (auto &x : ans[i]) printf(  %d , x);       puts(  );     }     return 0;   }   