此模板未验证正确性，抄书型模板，慎用。
struct Edge{ int from, to, cap, flow; }; int dfs(int x, int a); struct Dinic{ int n, m, s, t; //结点数，边数（包括反向弧），原点编号和汇点编号 vector<Edge> edges; //边表。edges[e]和edges[e^1]互为反向弧 vector<int> g[N]; //邻接表。 bool vis[N]; int d[N]; //从起点到i的距离 int cur[N]; //当前弧下标 void Add_edge(int from, int to, int cap){ edges.push_back((Edge) {from, to, cap, 0}); edges.push_back((Edge) {to, from, 0, 0}); 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){ vis[e.to] = 1; d[e.to] = d[x] + 1; Q.push(e.to); } } } return vis[t]; } int Maxflow(int s, int t){ this->s = s; this->t = t; int flow = 0; while(bfs()){ memset(cur, 0, sizeof(cur)); flow += dfs(s, inf); } return flow; } }; int dfs(int x, int a){ if(x == t || a == 0) return a; int 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; }