spoj 371 Boxes

 1 #include<cstring>
 2 #include<cstdio>
 3 #include<iostream>
 4 #include<algorithm>
 5 #include<queue>
 6 using namespace std;
 7 const int dian=1005;
 8 const int bian=6005;
 9 const int INF=0x3f3f3f3f;
10 int h[dian],nxt[bian],ver[bian],val[bian],cos[bian],with[dian],minn[dian];
11 int d[dian],v[dian];
12 int map[dian];
13 int n,tot;
14 int S,T;
15 void add(int a,int b,int c,int d){
16     tot++;ver[tot]=b;val[tot]=c;cos[tot]=d;nxt[tot]=h[a];h[a]=tot;
17     tot++;ver[tot]=a;val[tot]=0;cos[tot]=-d;nxt[tot]=h[b];h[b]=tot;
18 }
19 bool tell(){
20     memset(v,0,sizeof(v));
21     memset(d,0x3f,sizeof(d));
22     memset(with,0,sizeof(with));
23     memset(minn,0x3f,sizeof(minn));
24     queue<int>q;
25     q.push(S);
26     v[S]=1;
27     d[S]=0;
28     while(!q.empty()){
29         int x=q.front();
30         q.pop();
31         v[x]=0;
32         for(int i=h[x];i;i=nxt[i]){
33             int y=ver[i];
34             if(d[y]>d[x]+cos[i]&&val[i]){
35                 d[y]=d[x]+cos[i];
36                 minn[y]=min(minn[x],val[i]);
37                 with[y]=i;
38                 if(!v[y]){
39                     v[y]=1;
40                     q.push(y);
41                 }
42             }
43         }
44     }
45     if(d[T]==0x3f3f3f3f)
46         return 0;
47     return 1;
48 }
49 int zeng(){
50     for(int i=T;i!=S;i=ver[with[i]^1]){
51         val[with[i]]-=minn[T];
52         val[with[i]^1]+=minn[T];
53     }
54     return minn[T]*d[T];
55 }
56 int dinic_cost(){
57     int r=0;
58     while(tell())
59         r+=zeng();
60     return r;
61 }
62 int main(){
63     int cas;
64     scanf("%d",&cas);
65     while(cas--){
66         memset(h,0,sizeof(h));
67         memset(nxt,0,sizeof(nxt));
68         tot=1;
69         scanf("%d",&n);
70         S=n+1,T=n+2;
71         for(int i=1;i<=n;i++)
72             scanf("%d",&map[i]);
73         for(int i=1;i<=n;i++){
74             if(map[i]>1)
75                 add(S,i,map[i]-1,0);
76             else if(!map[i])
77                 add(i,T,1,0);
78             add(i,(i==1)?n:i-1,INF,1);
79             add(i,(i==n)?1:i+1,INF,1);
80         }
81         printf("%d\n",dinic_cost());
82     }
83     return 0;
84 }