bzoj 2763: [JLOI2011]飞行路线

Posted 2020-06-27 xiyuedong

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<iostream>
 4 #include<queue>
 5 #define pa pair<int,int>
 6 #define inf 0x7fffffff
 7 #define M 400008
 8 using namespace std;
 9 int d[M],f[M],n,m,k,s,t,cnt,head[M],next[10*M],u[10*M],v[10*M];
10 void jia(int a1,int a2,int a3)
11 {
12     cnt++;
13     next[cnt]=head[a1];
14     head[a1]=cnt;
15     u[cnt]=a2;
16     v[cnt]=a3;
17     return;
18 }
19 int main()
20 {
21     scanf("%d%d%d",&n,&m,&k);
22     scanf("%d%d",&s,&t);
23     for(int i=1;i<=m;i++)
24       {
25         int a1,a2,a3;
26         scanf("%d%d%d",&a1,&a2,&a3);
27         jia(a1,a2,a3);
28         jia(a2,a1,a3);
29         for(int j=1;j<=k;j++)
30           {
31             jia(j*n+a1,j*n+a2,a3);
32             jia(j*n+a2,j*n+a1,a3);
33             jia((j-1)*n+a1,j*n+a2,0);
34             jia((j-1)*n+a2,j*n+a1,0);
35           }
36       }
37     priority_queue<pa,vector<pa>,greater<pa> >q;
38     memset(d,60,sizeof(d));
39     q.push(make_pair(0,s));
40     d[s]=0;
41     for(;!q.empty();)
42       {
43         int now=q.top().second;
44         q.pop();
45         if(f[now])
46           continue;
47         f[now]=1;
48         for(int i=head[now];i;i=next[i])
49           if(d[u[i]]>d[now]+v[i])
50             {
51                 d[u[i]]=d[now]+v[i];
52                 q.push(make_pair(d[u[i]],u[i]));
53             }
54       }
55     int ans=inf;
56     for(int i=0;i<=k;i++)
57       ans=min(ans,d[i*n+t]);
58     printf("%d\n",ans);
59     return 0;
60 }

分层图按k分层