func_code_string: #include <bits/stdc++.h>   using namespace std;   const int maxn = 5000;   const double INF = 1e18;   const double ep = 1e-8;   struct Edge {     int from, to;     long long cap, flow;     int id;     Edge() {}     Edge(int u, int v, long long c, long long f, int id_)         : from(u), to(v), cap(c), flow(f), id(id_) {}   };   struct Dinic {     int n, m, s, t;     vector<Edge> edges;     vector<int> G[maxn];     int d[maxn], cur[maxn];     bool vis[maxn];     void init(int n) {       for (int i = 0; i < maxn; i++) G[i].clear();       edges.clear();     }     void add(int from, int to, long long cap, int id) {       edges.push_back(Edge(from, to, cap, 0, id));       edges.push_back(Edge(to, from, 0, 0, -1));       m = edges.size();       G[from].push_back(m - 2);       G[to].push_back(m - 1);     }     bool BFS() {       memset(vis, 0, sizeof(vis));       queue<int> Q;       Q.push(s);       d[s] = 0;       vis[s] = 1;       while (!Q.empty()) {         int x = Q.front();         Q.pop();         for (int i = 0; i < G[x].size(); i++) {           Edge& e = edges[G[x][i]];           if (!vis[e.to] && e.cap - e.flow > ep) {             vis[e.to] = 1;             d[e.to] = d[x] + 1;             Q.push(e.to);           }         }       }       return vis[t];     }     long long DFS(int x, long long a) {       if (x == t || a == 0) return a;       long long flow = 0, f;       for (int& i = cur[x]; i < G[x].size(); i++) {         Edge& e = edges[G[x][i]];         if (d[x] + 1 == d[e.to] && (f = DFS(e.to, min(a, e.cap - e.flow))) > 0) {           e.flow += f;           edges[G[x][i] ^ 1].flow -= f;           flow += f;           a -= f;           if (a == 0) break;         }       }       return flow;     }     long long maxFlow(int s, int t) {       this->s = s;       this->t = t;       long long flow = 0;       while (BFS()) {         memset(cur, 0, sizeof(cur));         flow += DFS(s, INF);       }       return flow;     }     void show() {       for (auto& e : edges) {         printf( (%d -> %d) => cap = %lld , flow = %lld n , e.from, e.to, e.cap,                e.flow);       }     }     void DFS2(int v) {       vis[v] = true;       for (int i = 0; i < G[v].size(); ++i) {         Edge e = edges[G[v][i]];         if (!vis[e.to] && e.cap - e.flow > ep) {           DFS2(e.to);         }       }     }     void showMinCut(int v) {       DFS2(v);       for (auto& e : edges) {         if (vis[e.from] && !vis[e.to] && e.cap != 0 && e.flow != 0)           printf( (%d -> %d) => cap = %lld , flow = %lld n , e.from, e.to, e.cap,                  e.flow);       }     }   };   int N1, N2, M;   int deg[4005];   vector<int> ans[2005];   int s, t, tot;   int main() {     Dinic G;     scanf( %d %d %d , &N1, &N2, &M);     tot = N1 + N2 + 15;     s = tot - 2, t = tot - 1;     G.init(tot);     for (int i = 1; i <= M; ++i) {       int x, y;       scanf( %d %d , &x, &y);       G.add(x, N1 + y, 1, i);       ++deg[x];       ++deg[y + N1];     }     int min_deg = M + 10;     for (int i = 1; i <= N1 + N2; ++i) {       min_deg = min(min_deg, deg[i]);     }     for (int i = 1; i <= N1; ++i) {       G.add(s, i, deg[i] - min_deg, -1);     }     for (int i = 1; i <= N2; ++i) {       G.add(i + N1, t, deg[i + N1] - min_deg, -1);     }     for (int k = min_deg; ~k; --k) {       G.maxFlow(s, t);       for (auto& e : G.edges) {         if (e.from >= 1 && e.from <= N1 && e.to >= N1 + 1 && e.to <= N2 + N1) {           if (e.flow == 0 && e.cap == 1) {             ans[k].push_back(e.id);           }         }       }       for (int i = 1; i <= N1; ++i) {         G.add(s, i, 1, -1);       }       for (int i = 1; i <= N2; ++i) {         G.add(i + N1, t, 1, -1);       }     }     for (int i = 0; i <= min_deg; ++i) {       printf( %d  , (int)ans[i].size());       for (int j : ans[i]) {         printf( %d  , j);       }       printf(  n );     }   }   