TOJ--2674--最短路(spfa)

 1 #include <iostream>
 2 #include <queue>
 3 #include <algorithm>
 4 #include <cstring>
 5 using namespace std;
 6 
 7 const int inf = 0x3f3f3f3f;
 8 const int size = 1010;
 9 
10 int map[size][size];
11 int dist[size];
12 int go[size];
13 bool vis[size];
14 
15 void spfa()
16 {
17     int i , now;
18     memset(vis, false, sizeof(vis));
19     for(i = 0; i < size; i++) 
20         dist[i] = (i==0)?0:inf;
21     queue<int>qe;
22     while( !qe.empty() )
23         qe.pop();
24     qe.push(0);
25     vis[0] = true;
26     while(!qe.empty())
27     {
28         now = qe.front();
29         for(i = 0; i < size; i++)
30         {
31             if(dist[i] > dist[now] + map[now][i])
32             {
33                 dist[i] = dist[now] + map[now][i];
34                 if( !vis[i] )
35                 {
36                     qe.push(i);
37                     vis[i] = true;
38                 }
39             }
40         }    
41         qe.pop();
42         vis[now] = false;
43     }
44 }
45 
46 int main()
47 {
48     int t , s ,d;
49     int i , j , mmin;
50     int next, st, end, len;
51     while( ~scanf("%d %d %d", &t, &s, &d) )
52     {
53         for(i = 0; i < size; i++)
54             for(j = 0; j <=i; j++)
55                 if(i == j)
56                     map[i][j] = 0;
57                 else
58                     map[i][j] = map[j][i] = inf;
59         while(t--)
60         {
61             scanf("%d %d %d", &st, &end, &len); 
62             if( len < map[st][end] )
63                 map[st][end] = map[end][st] = len;
64         }
65         for(i = 0; i < s; i++)  
66         {
67             scanf("%d", &next);
68             map[0][next] = map[next][0] = 0;
69         }
70         for(i = 0; i < d; i++)  
71             scanf( "%d",&go[i] );
72         spfa();
73         mmin = inf;
74         for(i = 0; i < d; i++)  
75         {
76             if( dist[ go[i] ] < mmin )
77                 mmin = dist[ go[i]  ];
78         }
79         printf("%d\n", mmin);
80     }
81     return 0;
82 }