POJ 1847

Posted 2021-01-13 huluxin

 1 #include <cstdio>
 2 #include <cmath>
 3 #include <cstring>
 4 #include <algorithm>
 5 #include <queue>
 6 #include <stack>
 7 #include <vector>
 8 #include <iomanip>
 9 using namespace std;
10 int n,s,t,d[150];
11 vector<pair<int,int> >e[150];
12 int main(int argc, char *argv[])
13 {
14     scanf("%d%d%d",&n,&s,&t);
15     for(int i=1;i<=n;i++)
16     {
17         int m;
18         scanf("%d",&m);
19         for(int j=0;j<m;j++)
20         {
21             int k;
22             scanf("%d",&k);
23             if(j!=0)
24             e[i].push_back(make_pair(k,1));
25             else
26             e[i].push_back(make_pair(k,0));
27         }
28     }
29     memset(d,0x3f3f3f3f,sizeof(d));
30     d[s]=0;
31     priority_queue<pair<int,int> >q;
32     q.push(make_pair(-d[s],s));
33     while(!q.empty())
34     {
35         int now=q.top().second;q.pop();
36         for(int i=0;i<e[now].size();i++)
37         {
38             int v=e[now][i].first;
39             if(d[v]>d[now]+e[now][i].second)
40             {
41                 d[v]=d[now]+e[now][i].second;
42                 q.push(make_pair(-d[v],v));
43             }
44             
45         }
46     }
47     if(d[t]==0x3f3f3f3f)
48     printf("-1
");
49     else
50     printf("%d
",d[t]);
51     return 0;
52 }