博客

struct edge {
    int to, capacity, cost, rev;
    edge() {}
    edge(int to, int _capacity, int _cost, int _rev) :to(to), capacity(_capacity), cost(_cost), rev(_rev) {}
};
struct Min_Cost_Max_Flow {
    int V, H[maxn + 5], dis[maxn + 5], PreV[maxn + 5], PreE[maxn + 5];
    vector<edge> G[maxn + 5];
    void Init(int n) {
        V = n;
        for (int i = 0; i <= V; ++i)G[i].clear();
    }
    void Add_Edge(int from, int to, int cap, int cost) {
        G[from].push_back(edge(to, cap, cost, G[to].size()));
        G[to].push_back(edge(from, 0, -cost, G[from].size() - 1));
    }
    int Min_cost_max_flow(int s, int t, int f, int& flow) {
        int res = 0; fill(H, H + 1 + V, 0);
        while (f) {
            priority_queue <pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>> > q;
            fill(dis, dis + 1 + V, INF);
            dis[s] = 0; q.push(pair<int, int>(0, s));
            while (!q.empty()) {
                pair<int, int> now = q.top(); q.pop();
                int v = now.second;
                if (dis[v] < now.first)continue;
                for (int i = 0; i < G[v].size(); ++i) {
                    edge& e = G[v][i];
                    if (e.capacity > 0 && dis[e.to] > dis[v] + e.cost + H[v] - H[e.to]) {
                        dis[e.to] = dis[v] + e.cost + H[v] - H[e.to];
                        PreV[e.to] = v;
                        PreE[e.to] = i;
                        q.push(pair<int, int>(dis[e.to], e.to));
                    }
                }
            }
            if (dis[t] == INF)break;
            for (int i = 0; i <= V; ++i)H[i] += dis[i];
            int d = f;
            for (int v = t; v != s; v = PreV[v])d = min(d, G[PreV[v]][PreE[v]].capacity);
            f -= d; flow += d; res += d*H[t];
            for (int v = t; v != s; v = PreV[v]) {
                edge& e = G[PreV[v]][PreE[v]];
                e.capacity -= d;
                G[v][e.rev].capacity += d;
            }
        }
        return res;
    }
    int Max_cost_max_flow(int s, int t, int f, int& flow) {
        int res = 0;
        fill(H, H + 1 + V, 0);
        while (f) {
            priority_queue <pair<int, int>> q;
            fill(dis, dis + 1 + V, -INF);
            dis[s] = 0;
            q.push(pair<int, int>(0, s));
            while (!q.empty()) {
                pair<int, int> now = q.top(); q.pop();
                int v = now.second;
                if (dis[v] > now.first)continue;
                for (int i = 0; i < G[v].size(); ++i) {
                    edge& e = G[v][i];
                    if (e.capacity > 0 && dis[e.to] < dis[v] + e.cost + H[v] - H[e.to]) {
                        dis[e.to] = dis[v] + e.cost + H[v] - H[e.to];
                        PreV[e.to] = v;
                        PreE[e.to] = i;
                        q.push(pair<int, int>(dis[e.to], e.to));
                    }
                }
            }
            if (dis[t] == -INF)break;
            for (int i = 0; i <= V; ++i)H[i] += dis[i];
            int d = f;
            for (int v = t; v != s; v = PreV[v])d = min(d, G[PreV[v]][PreE[v]].capacity);
            f -= d; flow += d;
            res += d*H[t];
            for (int v = t; v != s; v = PreV[v]) {
                edge& e = G[PreV[v]][PreE[v]];
                e.capacity -= d;
                G[v][e.rev].capacity += d;
            }
        }
        return res;
    }
}G;