func_code_string: #include <bits/stdc++.h>   using namespace std;   vector<int> graph[100001];   int color[100001];   vector<int> b, w;   void bfs(int v) {     queue<int> q;     q.push(v);     color[v] = 1;     b.push_back(v);     while (!q.empty()) {       int v = q.front();       q.pop();       for (int u : graph[v]) {         if (color[u] == 0) {           if (color[v] == 1)             color[u] = 2, w.push_back(u);           else             color[u] = 1, b.push_back(u);           q.push(u);         }         if (color[v] == color[u]) {           printf( -1 );           exit(0);         }       }     }   }   int main() {     int n, m;     scanf( %d %d , &n, &m);     while (m--) {       int a, b;       scanf( %d %d , &a, &b);       graph[a].push_back(b);       graph[b].push_back(a);     }     for (int i = 1; i <= n; i++)       if (color[i] == 0) bfs(i);     printf( %d n , (int)b.size());     for (int i = 0; i < b.size(); i++) printf( %d  , b[i]);     printf(  n%d n , (int)w.size());     for (int i : w) printf( %d  , i);     return 0;   }   