poj2516Minimum Cost

http://poj.org/problem?id=2516

建图的时候有个地方写错了卡了半年。。

题意看了N久啊有N个店主需要K种物品有M个供应点每个供应点有K种物品其实是算K次最小费用然后叠加分解开来这题就是求把某种物品从供应点送到店主那里

多个源点-》多个汇点所以加一个超级源点和超级汇点源点->M个供应点->N个店主->汇点所以共有m+n+2条边套最小费用模板就行了

View Code

  1 #include <iostream>
  2 #include<cstring>
  3 #include<cstdio>
  4 #include<algorithm>
  5 #include<queue>
  6 #define MN 10000
  7 #define MM 10000
  8 #define INF 0xfffffff
  9 using namespace std;
 10 struct node
 11 {
 12     int u,v,cost,cap,next;
 13 }edge[MM];
 14 int head[MN],t,vis[MN],dist[MN],co[55][55][55],sh[55][55],sto[55][55],pp[MN],flow;
 15 void init()
 16 {
 17     t = 0;
 18     memset(head,-1,sizeof(head));
 19 }
 20 void add(int u,int v,int c,int p)
 21 {
 22     edge[t].u = u;
 23     edge[t].v = v;
 24     edge[t].cap = c;
 25     edge[t].cost = p;
 26     edge[t].next = head[u];
 27     head[u] = t++;
 28     edge[t].v = u;
 29     edge[t].u = v;
 30     edge[t].cap = 0;
 31     edge[t].cost = -p;
 32     edge[t].next = head[v];
 33     head[v] = t++;
 34 }
 35 int spfa(int s,int en,int n)
 36 {
 37     int i,j,u,v;
 38     for(i =0 ; i <= n ; i++)
 39     dist[i] = INF;
 40     memset(vis,0,sizeof(vis));
 41     memset(pp,-1,sizeof(pp));
 42     queue<int>q;
 43     q.push(s);
 44     vis[s] = 1;
 45     dist[s] = 0;
 46     while(!q.empty())
 47     {
 48         u = q.front();
 49         q.pop();
 50         vis[u] = 0;
 51         for(i = head[u] ; i != -1 ; i = edge[i].next)
 52         {
 53             v = edge[i].v;
 54             if(edge[i].cap&&dist[v]>dist[u]+edge[i].cost)
 55             {
 56                 dist[v] = dist[u]+edge[i].cost;
 57                 //cout<<dist[v]<<endl;
 58                 pp[v] = i;
 59                 if(!vis[v])
 60                 {
 61                     vis[v] = 1;
 62                     q.push(v);
 63                 }
 64             }
 65         }
 66     }
 67     //cout<<dist[en]<<" ";
 68     if(dist[en]==INF)
 69     return 0;
 70     return 1;
 71 }
 72 int mcmf(int s,int en,int n)
 73 {
 74     int i,minf,minc=0;
 75     while(spfa(s,en,n))
 76     {
 77         minf = INF+1;
 78         for(i = pp[en] ; i != -1 ; i = pp[edge[i].u])
 79         {
 80             if(edge[i].cap<minf)
 81             minf = edge[i].cap;
 82         }
 83         flow+=minf;
 84         for(i = pp[en] ; i != -1 ; i = pp[edge[i].u])
 85         {
 86             edge[i].cap-=minf;
 87             edge[i^1].cap+=minf;
 88         }
 89         minc+=minf*dist[en];
 90     }
 91     return minc;
 92 }
 93 int main()
 94 {
 95     int i,j,n,m,k,g;
 96     while(cin>>n>>m>>k)
 97     {
 98         if(n==0&&m==0&&k==0)
 99         break;
100         int flag = 0,ss=0;
101         for(i = 1; i <= n ; i++)
102             for(j = 1; j <= k ; j++)
103                 cin>>sh[i][j];
104         for(i = 1; i <= m ; i++)
105              for(j = 1; j <= k ; j++)
106                 cin>>sto[i][j];
107         for(i = 1;i <= k ; i++)
108             for(j = 1 ; j <= n ; j++)
109                 for(g = 1; g <= m ; g++)
110                 cin>>co[i][j][g];
111         int s = 0,en = n+m+1;
112         for(i = 1; i <= k ; i++)
113         {
114             init();
115             int sa=0;
116             for(j = 1 ; j <= n ; j++)
117             {
118                add(m+j,en,sh[j][i],0);
119                sa+=sh[j][i];
120             }
121             for(j = 1; j <= m ; j++)
122                 add(s,j,sto[j][i],0);
123             for(j = 1; j <= m ; j++)
124                 for(g = 1 ; g <= n ; g++)
125                     add(j,m+g,INF,co[i][g][j]);
126             flow=0;
127             ss+=mcmf(s,en,n+m+1);
128             if(sa>flow)
129                 break;
130         }
131         if(i==k+1)
132         cout<<ss<<endl;
133         else
134         cout<<"-1\n";
135     }
136     return 0;
137 }