POJ　2837 Til the Cows Come Home

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 using namespace std;
 5 int w[1010][1010],dis[1010],team[1010*8];
 6 bool exist[1010];
 7 void SPFA(int s)
 8 {
 9     int head=0,tail=1,k=0;
10     team[head]=s;
11     dis[s]=0;
12     while(head<tail)
13     {
14         k=team[head];
15         exist[k]=false;
16         for(int i=s;i>=1;i--)
17         {
18             if((w[k][i]>0)&&(dis[i]>dis[k]+w[k][i]))
19             {
20                 dis[i]=dis[k]+w[k][i];
21                 if(!exist[i])
22                 {
23                     team[tail++]=i;
24                     exist[i]=true;
25                     
26                  } 
27             }
28         }
29         head++;
30     }
31 //    return dis[n];
32 }
33 int main()
34 {
35     int T,N,x,y,z;
36     cin>>T>>N;
37     for(int i=1;i<=T;i++)
38     {
39         cin>>x>>y>>z;
40         if(w[x][y]==0) w[x][y]=w[y][x]=z;
41         else if(w[x][y]>z) w[y][x]=w[x][y]=z;
42         
43     }
44     for(int i=1;i<=1100;i++) dis[i]=999999;
45     SPFA(N);
46     cout<<dis[1];
47     return 0;
48 }