• mcmf的dijkstra板子(来自PHY学长)


    struct MCMF {
        struct edge {
            int to, cap, cost, rev;
            //edge() {}
            //edge(int to, int _cap, int _cost, int _rev) : to(to), cap(_cap), cost(_cost), rev(_rev) {}
        };
    
        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 addedge(int from, int to, int cap, int cost) {
            G[from].emplace_back(edge{to, cap, cost, (int) G[to].size()});
            G[to].emplace_back(edge{from, 0, -cost, (int) G[from].size() - 1});
        }
    
        int mcmf(int s, int t) {
            int res = 0, flow = 0;
            fill(H, H + 1 + V, 0);
            int f = inf;
            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, Size;
                    if (dis[v] < -now.first)continue;
                    Size = G[v].size();
                    for (int i = 0; i < Size; ++i) {
                        edge e = G[v][i];
                        if (e.cap > 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]].cap);
                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.cap -= d;
                    G[v][e.rev].cap += d;
                }
            }
            return res;
        }
    } G;
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  • 原文地址:https://www.cnblogs.com/liuquanxu/p/11436928.html
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