BZOJ 1834: [ZJOI2010]network 网络扩容（网络流+费用流）

一看就知道是模板题= = ，不说什么了= =

PS：回去搞期末了，暑假再来刷题了

CODE：

  1 #include<cstdio>
  2 #include<iostream>
  3 #include<cstring>
  4 #include<algorithm>
  5 #include<queue>
  6 #define maxn 1010
  7 #define maxm 20010
  8 #define inf 0x7fffffff
  9 using namespace std;
 10 struct edges{
 11     int to,next,cap,dist;bool b;
 12 }edge[maxm];
 13 int n,m,s,t,k,l;
 14 int next[maxn],dist[maxn],way[maxn],h[maxn],p[maxn],gap[maxn];
 15 bool b[maxn];
 16 queue<int> q;
 17 int addedge(int from,int to,int cap,int dist,bool bo){
 18     l++;
 19     edge[l*2]=(edges){to,next[from],cap,dist,bo};
 20     edge[l*2+1]=(edges){from,next[to],0,-dist,bo};
 21     next[from]=l*2;next[to]=l*2+1;
 22     return 0;
 23 }
 24 bool spfa(){
 25     memset(b,0,sizeof(b));
 26     for (int i=1;i<=n;i++) dist[i]=inf;
 27     dist[1]=0;
 28     q.push(1);
 29     while (!q.empty()){
 30     int u=q.front();q.pop();
 31     b[u]=0;
 32     for (int i=next[u];i;i=edge[i].next)
 33         if (edge[i].cap&&dist[edge[i].to]>dist[u]+edge[i].dist) {
 34         dist[edge[i].to]=dist[u]+edge[i].dist;
 35         way[edge[i].to]=i;
 36         if(!b[edge[i].to]){
 37             b[edge[i].to]=1;
 38             q.push(edge[i].to);
 39         }
 40         }
 41     }
 42     if (dist[t]==inf) return 0;
 43     return 1;
 44 }
 45 int mcmf(int cap){
 46     int cost=0;
 47     while (spfa()){
 48     int x=n,flow=inf;
 49     while (x!=1){
 50         flow=min(flow,edge[way[x]].cap);
 51         x=edge[way[x]^1].to;
 52     }
 53     if (flow>=cap) return (cost+=dist[n]*cap);
 54     cost+=dist[n]*flow;
 55     cap-=flow;
 56     x=n;
 57     while(x!=1){
 58         edge[way[x]].cap-=flow;
 59         edge[way[x]^1].cap+=flow;
 60         x=edge[way[x]^1].to;
 61     }
 62     }
 63     return cost;
 64 }
 65 int sap(int u,int flow){
 66     if (u==t) return flow;
 67     int cur=0;
 68     for (int i=p[u];i;i=edge[i].next)
 69     if (edge[i].b&&edge[i].cap&&h[u]==h[edge[i].to]+1){
 70         int cut=sap(edge[i].to,min(flow-cur,edge[i].cap));
 71         edge[i].cap-=cut;edge[i^1].cap+=cut;
 72         p[u]=i;
 73         if ((cur+=cut)==flow ) return flow;
 74     }
 75     if (!(--gap[h[u]])) h[s]=n;
 76     gap[++h[u]]++;
 77     p[u]=next[u];
 78     return cur;
 79 }
 80 int maxflow(){
 81     memset(gap,0,sizeof(gap));
 82     memset(h,0,sizeof(h));
 83     gap[0]=n;
 84     for(int i=1;i<=n;i++) p[i]=next[i];     
 85     int flow=0;
 86     while (h[s]<n) flow+=sap(s,inf);
 87     return flow;
 88 } 
 89 int main(){
 90     scanf("%d%d%d",&n,&m,&k);
 91     s=1,t=n;
 92     for (int i=1;i<=m;i++) {
 93     int x,y,cap,d;
 94     scanf("%d%d%d%d",&x,&y,&cap,&d);
 95     addedge(x,y,cap,0,1);
 96     addedge(x,y,inf,d,0);
 97     }
 98     int ans=maxflow();
 99     printf("%d %d\n",ans,mcmf(k));
100     return 0;
101 }
View Code

 

 
 
posted @ 2014-06-22 10:28  New_Godess  阅读(182)  评论(0)  编辑  收藏  举报