func_code_string: #include <bits/stdc++.h>   using namespace std;   const int MAX_N = 200000;   const int MAX_L = MAX_N * 2;   vector<int> nbrs[MAX_N];   int ps[MAX_N], cis[MAX_N], vs[MAX_L];   bool used[MAX_N];   int main() {     int n, m, k;     scanf( %d%d%d , &n, &m, &k);     for (int i = 0; i < m; i++) {       int u, v;       scanf( %d%d , &u, &v);       u--, v--;       nbrs[u].push_back(v);       nbrs[v].push_back(u);     }     ps[0] = -1;     int l = 0;     for (int u = 0; u >= 0;) {       vector<int> &nbru = nbrs[u];       if (cis[u] == 0) {         vs[l++] = u;         used[u] = true;       }       while (cis[u] < nbru.size() && used[nbru[cis[u]]]) cis[u]++;       if (cis[u] < nbru.size()) {         int v = nbru[cis[u]++];         ps[v] = u;         u = v;       } else {         int v = ps[u];         if (v >= 0) vs[l++] = v;         u = v;       }     }     int q = l / k, r = l % k;     for (int i = 0, j = 0; i < k; i++) {       int ci = q + ((i < r) ? 1 : 0);       printf( %d , ci);       while (ci--) printf(  %d , vs[j++] + 1);       putchar(  n );     }     return 0;   }   