[gotoac]费用流spfa beta1

struct costFlow{//邻接表typedef int type;struct edge{int from,to;type flow,cost;edge(int u=0,int v=0,type f=0,type c=0){from=u,to=v,flow=f,cost=c;}};vector<edge>edg;  //边表vector<int>g[M];  //邻接表int n,m;          //顶点数,边数int inq[M],dis[M];//是否在队列中,距离起点的距离int pre[M],aug[M];//上一条弧,可改进量void init(int _n){n=_n,edg.clear();for(int i=0;i<n;i++) g[i].clear();}void insert(int u,int v,type f,type c){edg.push_back(edge(u,v,f,c)),edg.push_back(edge(v,u,0,-c));m=edg.size();g[u].push_back(m-2),g[v].push_back(m-1);}bool spfa(int s,int t,type& flow,type& cost){for(int i=0;i<n;i++) dis[i]=INF;clr(inq,0,n);dis[s]=0,inq[s]=1,pre[s]=0,aug[s]=INF;queue<int>q;for(q.push(s);!q.empty();){int u=q.front();q.pop();inq[u]=0;for(int i=0;i<g[u].size();i++){edge& e=edg[g[u][i]];if(e.flow>0 && dis[e.to]>dis[u]+e.cost){dis[e.to]=dis[u]+e.cost;pre[e.to]=g[u][i];aug[e.to]=_min(aug[u],e.flow);if(!inq[e.to]) q.push(e.to),inq[e.to]=1;}}}if(dis[t]==INF) return false;flow+=aug[t],cost+=aug[t]*dis[t];for(int u=t;u!=s;u=edg[pre[u]].from){edg[pre[u]].flow-=aug[t];edg[pre[u]^1].flow+=aug[t];}return true;}type minCost(int s,int t){type flow=0,cost=0;while(spfa(s,t,flow,cost));return cost;}}p;