hdu 6118(费用流)

裸的费用流 因为没有负环  因此可以建图  不需要跑最大流 所以在费用为正的时候return就行了

#include <cstdio>
#include <cmath>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <cstdlib>
#include <queue>
#include <vector>
using namespace std;
struct Edge
{
    long long from, to;
    long long cap, flow, cost;
};
const int maxn = 505 * 4 + 5;
const long long INF = 0x7fffffffffffffff;
long long a[505], b[505], c[505], d[505];
long long g[505][505];
struct MCMF
{
    long long n, m, s, t;
    vector<Edge> edges;
    vector<long long> G[maxn];
    long long inq[maxn], d[maxn], p[maxn], a[maxn];

    void init(long long n)
    {
        this->n = n;
        for(int i = 0; i < n; ++i)
            G[i].clear();
        edges.clear();
    }

    void AddEdge(long long from, long long to, long long cap, long long cost)
    {
        edges.push_back((Edge)
        {
            from, to, cap, 0, cost
        });
        edges.push_back((Edge)
        {
            to, from, 0, 0, -cost
        });
        m = edges.size();
        G[from].push_back(m - 2);
        G[to].push_back(m - 1);
    }
    bool BellmanFord(long long s, long long t, long long &flow, long long &cost)
    {
        for(int i = 0; i < n; ++i)
            d[i] = INF;
        memset(inq, 0, sizeof(inq));
        d[s] = 0;
        inq[s] = 1;
        p[s] = 0;
        a[s] = INF;
        queue<long long> Q;
        Q.push(s);
        while(!Q.empty())
        {
            long long u = Q.front();
            Q.pop();
            inq[u] = 0;
            for(int i = 0; i < G[u].size(); ++i)
            {
                Edge &e = edges[G[u][i]];
                if(e.cap > e.flow && d[e.to] > d[u] + e.cost)
                {
                    d[e.to] = d[u] + e.cost;
                    p[e.to] = G[u][i];
                    a[e.to] = min(a[u], e.cap - e.flow);
                    if(!inq[e.to])
                    {
                        Q.push(e.to);
                        inq[e.to] = 1;
                    }
                }
            }
        }
        if(d[t] >= 0)
            return false;
        flow += a[t];
        cost += d[t] * a[t];
        long long u = t;
        while(u != s)
        {
            edges[p[u]].flow += a[t];
            edges[p[u] ^ 1].flow -= a[t];
            u = edges[p[u]].from;
        }
        return true;
    }
    long long Mincost(long long s, long long t)
    {
        long long flow = 0, cost = 0;
        while(BellmanFord(s, t, flow, cost))
        {

        };
        return cost;
    }
} mcmf;
int main()
{
    long long n, m;
    while(~scanf("%I64d%I64d", &n, &m))
    {
        memset(g, -1, sizeof(g));
        for(int i = 1; i <= n; ++i)
        {
            scanf("%I64d%I64d%I64d%I64d", &a[i], &b[i], &c[i], &d[i]);
            g[i][i] = 0;
        }
        mcmf.init(n + 2);
        for(int i = 0; i < m; ++i)
        {
            long long u, v, k;
            scanf("%I64d%I64d%I64d", &u, &v, &k);
            mcmf.AddEdge(u, v, INF, k);
            mcmf.AddEdge(v, u, INF, k);
        }
        for(int i = 1; i <= n; ++i)
        {
            mcmf.AddEdge(0, i, b[i], a[i]);
            mcmf.AddEdge(i, n + 1, d[i], -c[i]);
        }
        long long ans = -mcmf.Mincost(0, n + 1);
        printf("%I64d\n", ans);
    }
}