[BZOJ 1001 狼抓兔子]

 1 #include<cstdio>
 2 #include<cstdlib>
 3 #include<cstring>
 4 #include<iostream>
 5 #include<algorithm>
 6 #define N 1010
 7 #define inf 0x7fffffff
 8 using namespace std;
 9 
10 const int maxn=N*N*2,maxm=maxn*3;
11 int n,m,s,t,p,d,p1,p2;
12 int head[maxn],go[maxm],next[maxm],w[maxm];
13 
14 void build(int a,int b,int c)
15 {
16     go[++p]=b;
17     next[p]=head[a];
18     w[p]=c;
19     head[a]=p;
20 }
21 
22 void Double_build(int a,int b,int c)
23 {
24     build(a,b,c);
25     build(b,a,c);
26 }
27 
28 int num(int a,int b){return (((a-1)*(m-1)+b)*2);}
29 
30 int que[maxn],lead,tail,use[maxn],dis[maxn],node;
31 
32 void spfa()
33 {
34     memset(use,0,sizeof use);
35     for (int i=s;i<=t;i++) dis[i]=inf;
36     lead=tail=1;que[1]=s;use[s]=1;dis[s]=0;
37     for (;lead<=tail;lead++,use[node]=0)
38     {
39         node=que[lead%maxn];
40         for (int i=head[node];i;i=next[i]) if (dis[go[i]]>dis[node]+w[i])
41         {
42             dis[go[i]]=dis[node]+w[i];
43             if (!use[go[i]])
44             {
45                 use[go[i]]=1;
46                 que[(++tail)%maxn]=go[i];
47             }
48         }
49     }
50 }
51 
52 int main()
53 {
54     scanf("%d%d",&n,&m);
55     s=1;t=(n-1)*m*2;
56     for (int i=1;i<=n;i++)
57         for (int j=1;j<m;j++)
58         {
59             scanf("%d",&d);
60             p1=i==1?t:num(i-1,j)+1;p2=i==n?s:num(i,j);
61             Double_build(p1,p2,d);
62         }
63     for (int i=1;i<n;i++)
64         for (int j=1;j<=m;j++)
65         {
66             scanf("%d",&d);
67             p1=j==1?s:num(i,j-1);p2=j==m?t:num(i,j)+1;
68             Double_build(p1,p2,d);
69         }
70     for (int i=1;i<n;i++)
71         for (int j=1;j<m;j++)
72         {
73             scanf("%d",&d);
74             p1=num(i,j);p2=p1+1;
75             Double_build(p1,p2,d);
76         }
77     spfa();
78     printf("%d",dis[t]);
79     return 0;
80 }