struct mcmf { struct edge { int to; ll cap; ll flow; ll cost; int rev; int mark; }; vector> edges; vector dis; vector vis; ll ret; mcmf(int n) : edges(n + 1), dis(n + 1), vis(n + 1) {} void add_edge(int from, int to, ll cap, ll cost, int mark = 0, int mark_rev = 0) { edges[from].push_back({ to, cap, 0, cost, int(edges[to].size()), mark }); edges[to].push_back({ from, 0, 0, -cost, int(edges[from].size() - 1), mark_rev }); } bool sp(int s, int t) { dis.assign(edges.size(), INFLL); dis[s] = 0; int n = edges.size(); int f = 1; while (f) { f = 0; for (int i = 0; i < n; ++i) { for (auto&& [to, cap, flow, cost, rev, mark] : edges[i]) { if (cap > flow and dis[to] > dis[i] + cost) { dis[to] = dis[i] + cost; f = 1; } } } } return dis[t] != INFLL; } ll dfs(int s, int t, ll cap) { if (vis[s]) { return 0; } vis[s] = 1; if (s == t) { return cap; } ll res = 0; int n = edges[s].size(); for (int i = 0; i < n; ++i) { auto e = edges[s][i]; if (e.cap > e.flow and dis[e.to] == dis[s] + e.cost) { ll nw = dfs(e.to, t, min(cap - res, e.cap - e.flow)); edges[s][i].flow += nw; edges[e.to][e.rev].flow -= nw; res += nw; ret += nw * e.cost; if (res == cap) { return res; } } } return res; } // returns: (flow, cost) pll run(int s, int t) { ll res = 0; ret = 0; while (sp(s, t)) { vis.assign(edges.size(), 0); ll curr = dfs(s, t, LLONG_MAX); res += curr; // BUG: this is a temporary fix of the infinite-looping issue observed // when dealing with networks with negative weights. if (curr == 0) break; } return { res, ret }; } };