hdu 5988 費用流( vector浮點版 )

#include <bits/stdc++.h>
using namespace std;
typedef int lint;
typedef long long LL;
struct EDGE {
    int from, to, next, cap;  //  如果需要修改 cost爲LL
    double cost;
};
namespace MFMC {
    static const int maxn = 5005;
    const double inf = 1e10;
    const double eps = 1e-8;
    struct EDGE {
        int from, to, inv;
        int cap;
        double cost;
    };
    vector<vector<EDGE> > es;
    void init(int n) {
        for (auto& i : es)
            i.resize(0);
        es.resize(n+1);
    }
    void add(int u, int v, int cap, double cost) {  //  如果需要修改 cost爲LL
        es[u].push_back(EDGE{u, v, (int)es[v].size(), cap, cost});
        es[v].push_back(EDGE{v, u, (int)es[u].size() - 1, 0, -cost});
    }
//O(VE)
    template<typename DT>
    void spfa(int s, DT dist[], EDGE* rec[]) {
        queue<int> q;
        static bool inq[maxn];
        for( int i = 0; i <= es.size();i++ ){
            dist[i] = inf;
        }
        memset(inq, 0, es.size() * sizeof(bool));
        memset(rec, 0, es.size() * sizeof(int));
        dist[s] = 0;
        q.push(s);
        while (!q.empty()) {
            s = q.front();
            q.pop();
            inq[s] = false;
            for (auto& e : es[s]) {
                if (0 == e.cap)
                    continue;
                if (dist[e.to] > dist[s] + e.cost + eps ) {
                    dist[e.to] = dist[s] + e.cost;
                    rec[e.to] = &e;
                    if (!inq[e.to]) {
                        q.push(e.to);
                        inq[e.to] = true;
                    }
                }
            }
        }
    }

    template<typename DT>
    void dijkstra_pq(int s, DT dist[], EDGE* rec[]) {
        priority_queue<pair<DT, int> > q;//-dist, vertex
        for( int i = 0; i <= es.size();i++ ){
            dist[i] = inf;
        }
        memset(rec, 0, es.size() * sizeof(int));
        dist[s] = 0;
        q.push(make_pair(0, s));
        while (!q.empty()) {
            s = q.top().second;
            DT c = -q.top().first;
            q.pop();
            if (fabs(c - dist[s]) > eps) continue;
            for (auto& e : es[s]) {
                if (0 == e.cap)
                    continue;
                if (dist[e.to] > c + e.cost+eps) {
                    dist[e.to] = c + e.cost;
                    rec[e.to] = &e;
                    q.push(make_pair(-dist[e.to], e.to));
                }
            }
        }
    }

//Need dijkstra_GRAPH_EDGES_PQ
//O(FE log(E)),F is the maximum flow
    template<typename FT, typename CT>
    void mfmc(int s, int t, FT &maxflow, CT &mincost) {

        static CT dist[maxn];
        static EDGE* rec_e[maxn];
        maxflow = mincost = 0;
        CT realdist = 0;    //real distance from s to t

        bool first = true;
        while (true) {
            if (first) {
                spfa( s, dist, rec_e);
                first = false;
            } else {
                dijkstra_pq( s, dist, rec_e);
            }
            if (!fabs(inf-dist[t]))
                break;
            FT minF = numeric_limits<FT>::max();
            for (auto e = rec_e[t]; e; e = rec_e[e->from])
                minF = min(minF, (FT)e->cap);
            maxflow += minF;
            realdist += dist[t];
            mincost += minF * realdist;
            for (auto e = rec_e[t]; e; e = rec_e[e->from]) {
                e->cap -= minF;
                es[e->to][e->inv].cap += minF;
            }
            for (auto& i : es)
                for (auto& e : i)
                    e.cost += dist[e.from] - dist[e.to];
        }
    }
};
const int maxn = 205;
const int inf = 0x3f3f3f3f;
int s[maxn],b[maxn];
int main(){
    int ca;
    scanf("%d",&ca);
    while(ca--){
        int n,m;
        scanf("%d%d",&n,&m);
        int S = 0,T = 2*n+1;
        MFMC::init(T);
        for( int i = 1;i <= n;i++ ){
            scanf("%d%d",&s[i],&b[i]);
            MFMC::add( i,i+n,inf,0 );
            MFMC::add( S,i,s[i],0 );
            MFMC::add( i+n,T,b[i],0 );
        }
        double v;int x,y,c;
        for( int i = 1;i <= m;i++ ){
            scanf("%d%d%d%lf",&x,&y,&c,&v);
            v = 1-v;
            MFMC::add( x+n,y,1,0 );
            MFMC::add( x+n,y,c-1,-log(v) );
        }
        int maxflow;double mincost;
        MFMC::mfmc( S,T,maxflow,mincost );
        double ans= 1 - exp( -mincost );
        printf("%.2lf\n",ans);
    }
    return 0;
}