[板子]最小费用最大流(Dijkstra增广)

最小费用最大流板子，没有压行。利用重标号让边权非负，用Dijkstra进行增广，在理论和实际上都比SPFA增广快得多。教程略去。转载请随意。

 #include <cstdio>
 #include <cstring>
 #include <algorithm>
 #include <functional>
 #include <queue>
 using namespace std;

 ;
 const int inf = 0x33333333;
 typedef pair<int, int> int2;

 struct edge {
     int to, rev, cap, cost;
 };

 int n;
 vector<edge> G[maxn];

 void add_edge(int u, int v, int cap, int cost) {
     G[u].push_back((edge){v, (int)G[v].size(), cap, cost});
     G[v].push_back((edge){u, (, , -cost});
 }

 int2 mcmf(int s, int t) {
     //init
     static int h[maxn];        //标号
     , cost = ;
     //solve
     while(true) {
         //dijkstra init
         static int dist[maxn]; //距离
         static int pv[maxn];   //上一个顶点
         static int pe[maxn];   //上一条弧
         memset(dist, 0x33, sizeof dist);
         dist[s] = ;
         priority_queue< int2, vector<int2>, greater<int2> > q;
         q.push(int2(, s));
         //dijkstra
         while(!q.empty()) {
             int2 x = q.top();
             q.pop();
             int u = x.second;
             if(x.first != dist[u]) {
                 continue;
             }
             if(u == t) {
                 break;
             }
             ; i < (int)G[u].size(); ++i) {
                 edge &e = G[u][i];
                 int newcost = e.cost + h[u] - h[e.to];
                  && dist[e.to] > dist[u] + newcost) {
                     dist[e.to] = dist[u] + newcost;
                     q.push(int2(dist[e.to], e.to));
                     pv[e.to] = u;
                     pe[e.to] = i;
                 }
             }
         }
         if(dist[t] == inf) {
             break;
         }
         //augment
         ; i < n; ++i) {
             h[i] = min(h[i] + dist[i], inf);
         }
         int newflow = inf;
         for(int x = t; x != s; x = pv[x]) {
             edge &e = G[pv[x]][pe[x]];
             newflow = min(newflow, e.cap);
         }
         flow += newflow;
         cost += newflow * h[t];
         for(int x = t; x != s; x = pv[x]) {
             edge &e = G[pv[x]][pe[x]];
             e.cap -= newflow;
             G[x][e.rev].cap += newflow;
         }
     }
     return make_pair(flow, cost);
 }

 int main(void) {
     int m, source, sink;
     scanf("%d%d%d%d", &n, &m, &source, &sink), --source, --sink;
     ; i < m; ++i) {
         int u, v, cap, cost;
         scanf("%d%d%d%d", &u, &v, &cap, &cost), --u, --v;
         add_edge(u, v, cap, cost);
     }
     int2 ans = mcmf(source, sink);
     printf("%d %d\n", ans.first, ans.second);
     ;
 }