HDU 2066最短路径Dijkstra、

思路：枚举所有起点城市然后比较每个起点所去喜欢城市的最小距离

#include<cstdio>
#include<cmath>
#include<cstring>
const int qq=1000+10;
const int MAX=1e7;
int s[qq],e[qq];
int dist[qq];
int vis[qq],tar[qq];
int city[qq][qq];
int t,a,b;
void Dijkstra()
{
    int poor=MAX;
    for(int l=1;l<=a;++l){
        int tot=MAX;
        for(int i=1;i<qq;++i){
            vis[i]=0;
            dist[i]=city[s[l]][i];
        }
        vis[s[l]]=1;
        for(int i=1;i<qq;++i){
            int minx=MAX;
            int u=s[l];
            for(int j=1;j<qq;++j)
                if(!vis[j] && dist[j] < minx)
                    minx=dist[u=j];
            if(minx==MAX)    break;
            vis[u]=1;
            if(tar[u]!=0){
                tot=dist[u];
                break;
            }
            for(int j=1;j<qq;++j)
                if(!vis[j] && city[u][j] < MAX)
                    if(dist[u]+city[u][j]<dist[j])
                        dist[j] = dist[u] + city[u][j];        
        }
        if(tot<poor)
            poor=tot;
    }
    printf("%d
",poor);
}
int main()
{
    while(scanf("%d %d %d",&t,&a,&b)!=EOF){
        for(int j,i=1;i<qq;++i)
            for(j=1;j<qq;++j)
                city[i][j]=MAX;
        for(int i=1;i<=t;++i){
            int x,y,cost;
            scanf("%d %d %d",&x,&y,&cost);
            if(cost<city[x][y])
                city[x][y]=city[y][x]=cost;
        }
        for(int i=1;i<=a;++i)
            scanf("%d",&s[i]);
        memset(tar,0,sizeof(tar));
        for(int i=1;i<=b;++i){
            int ans;scanf("%d",&ans);
            tar[ans]=1;
        }
        Dijkstra();
    }
}