Method add_edge

code/graph/dinic.cpp:12–14

    memset(head = new int[n], -1, n*sizeof(int)); }
  void reset() { e = e_store; }
  void add_edge(int u, int v, int uv, int vu=0) {
    e.push_back(edge(v,uv,head[u])); head[u]=(int)size(e)-1;
    e.push_back(edge(u,vu,head[v])); head[v]=(int)size(e)-1;}
  int augment(int v, int t, int f) {
    if (v == t) return f;
    for (int &i = curh[v], ret; i != -1; i = e[i].nxt)