BZOJ 1001 狼抓兔子

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<cmath>
 5 #include<string>
 6 #include<algorithm>
 7 int next[7000005],first[7000005],go[7000005],tot,val[7000005];
 8 int dis[2000005],c[5000005],S,T,n,m,x,ans=0;
 9 
10 int sta(int x,int y){
11     return (x-1)*m+y;
12 }
13 void insert(int x,int y,int z){
14     tot++;
15     go[tot]=y;
16     next[tot]=first[x];
17     first[x]=tot;
18     val[tot]=z;
19     
20     tot++;
21     go[tot]=x;
22     next[tot]=first[y];
23     first[y]=tot;
24     val[tot]=z;
25 }
26 bool bfs(){
27     int now,i;
28     memset(dis,-1,sizeof dis);
29     int h=0,t=1;
30     c[1]=S;
31     dis[S]=0;
32     while (h<t){
33         h++;
34         now=c[h];
35         for (int i=first[now];i;i=next[i]){
36             int pur=go[i];
37             if (val[i]&&dis[pur]<0){
38                 c[++t]=pur;
39                 dis[pur]=dis[now]+1;
40             }
41         }
42     }
43     if (dis[T]==-1) return 0;
44     return 1;
45 }
46 int dfs(int x,int f){
47     if (x==T) return f;
48     int w,used=0;
49     for (int i=first[x];i;i=next[i]){
50         int pur=go[i];
51         if (val[i]&&dis[pur]==dis[x]+1){
52             w=f-used;
53             w=dfs(pur,std::min(w,val[i]));
54             val[i]-=w;
55             val[i+1]+=w;
56             used+=w;
57             if (used==f) return f;
58         }
59     }
60     if (!used) dis[x]=-1;
61     return used;
62 }
63 void dinic(){
64     while (bfs()) ans+=dfs(1,0x7fffffff);
65 }
66 int main(){
67     scanf("%d%d",&n,&m);
68     S=1;T=sta(n,m);
69     for (int i=1;i<=n;i++)
70      for (int j=1;j<=m-1;j++){
71          scanf("%d",&x);
72          insert(sta(i,j),sta(i,j+1),x);
73      }
74     for (int i=1;i<=n-1;i++)
75      for (int j=1;j<=m;j++){
76          scanf("%d",&x);
77          insert(sta(i,j),sta(i+1,j),x);
78      } 
79     for (int i=1;i<=n-1;i++)
80      for (int j=1;j<=m-1;j++){
81          scanf("%d",&x);
82          insert(sta(i,j),sta(i+1,j+1),x);
83      } 
84     dinic();
85     printf("%d",ans); 
86 }