P4015 运输问题 最大/最小费用最大流

P4015 运输问题

 #include <bits/stdc++.h>
 using namespace std;
 const int maxn = , inf = 0x3f3f3f3f;
 struct Edge {
     int from, to, cap, flow, cost;
 };
 struct MCMF {
     int n, m, s, t;
     vector<Edge> edges;
     vector<int> G[maxn];
     int inq[maxn];
     int d[maxn];
     int p[maxn];
     int a[maxn];

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

     void AddEdge(int from, int to, int cap, int cost) {
         edges.push_back((Edge){from, to, cap, , cost});
         edges.push_back((Edge){to, from, , , -cost});
         m = edges.size();
         G[from].push_back(m-);
         G[to].push_back(m-);
     }
     bool BellmanFord(int s, int t, int& flow, int& cost) {
         for (int i = ; i <= n; ++i) d[i] = inf;
         memset(inq, , sizeof(inq));
         d[s] = ; inq[s] = ; p[s] = ; a[s] = inf;

         queue<int> que;
         que.push(s);
         while (!que.empty()) {
             int u = que.front(); que.pop();
             inq[u] = ;
             for (int i = ; 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]) { que.push(e.to); inq[e.to] = ; }
                 }
             }
         }
         if (d[t] == inf) return false;
         flow += a[t];
         cost += d[t] * a[t];
         int u = t;
         while (u != s) {
             edges[p[u]].flow += a[t];
             edges[p[u]^].flow -= a[t];
             u = edges[p[u]].from;
         }
         return true;
     }
     int mincost(int s, int t) {
         int flow = , cost = ;
         while (BellmanFord(s, t, flow, cost));
         return cost;
     }
 }mcmf;
 int a[maxn], b[maxn], c[maxn][maxn];
 int main() {
     int m, n; scanf("%d%d",&m,&n);
     int s = m+n+, t = m+n+;

     for (int i = ; i <= m; ++i) scanf("%d",&a[i]);
     for (int j = ; j <= n; ++j) scanf("%d",&b[j]);
     for (int i = ; i <= m; ++i) {
         for (int j = ; j <= n; ++j) {
             scanf("%d",&c[i][j]);
         }
     }
     // 最小费用最大流
     mcmf.init(n+m+);
     for (int i = ; i <= m; ++i) {
         mcmf.AddEdge(s,i,a[i],);
     }
     for (int i = ; i <= m; ++i) {
         for (int j = ; j <= n; ++j) {
             mcmf.AddEdge(i,j+m,inf,c[i][j]);
         }
     }
     for (int j = ; j <= n; ++j) {
         mcmf.AddEdge(j+m,t,b[j],);
     }
     printf("%d\n",mcmf.mincost(s,t));

     // 最大费用最大流
     mcmf.init(n+m+);
     for (int i = ; i <= m; ++i) {
         mcmf.AddEdge(s,i,a[i],);
     }
     for (int i = ; i <= m; ++i) {
         for (int j = ; j <= n; ++j) {
             mcmf.AddEdge(i,j+m,inf,-c[i][j]);
         }
     }
     for (int j = ; j <= n; ++j) {
         mcmf.AddEdge(j+m,t,b[j],);
     }
     printf("%d\n",-mcmf.mincost(s,t));
     return ;
 }