hdu2066多源最短路

题目链接：http://icpc.njust.edu.cn/Problem/Hdu/2066/

SPFA可以高效过，代码如下：

 #include<bits/stdc++.h>
 using namespace std;
 typedef unsigned int ui;
 typedef long long ll;
 typedef unsigned long long ull;
 #define pf printf
 #define mem(a,b) memset(a,b,sizeof(a))
 #define prime1 1e9+7
 #define prime2 1e9+9
 #define pi 3.14159265
 #define lson l,mid,rt<<1
 #define rson mid+1,r,rt<<1|1
 #define scand(x) scanf("%llf",&x)
 #define f(i,a,b) for(int i=a;i<=b;i++)
 #define scan(a) scanf("%d",&a)
 #define mp(a,b) make_pair((a),(b))
 #define P pair<int,int>
 #define dbg(args) cout<<#args<<":"<<args<<endl;
 #define inf 0x3f3f3f3f
 const int maxn=1e4;
 int n,m,t,e;
 int head[maxn],in[maxn],nxt[maxn],d[maxn],a[maxn],ans,b;
 bool vis[maxn];
 struct edge{
     int v,w;
 }p[maxn];
 void init()
 {
     e=;
     mem(head,-);
     mem(nxt,-);
     mem(vis,);
 }
 void addedge(int u,int v,int w)
 {
     p[e].v=v;
     p[e].w=w;
     nxt[e]=head[u];
     head[u]=e++;
 }
 void SPFA(int src)
 {
         mem(in,);
         d[src]=;
         queue<int>q;
         q.push(src);
         in[src]=;
         while(!q.empty())
         {
             int now=q.front();
             q.pop();
             in[now]=;
             for(int i=head[now];~i;i=nxt[i])
             {
                 if(d[p[i].v]>d[now]+p[i].w)
                 {
                     d[p[i].v]=d[now]+p[i].w;
                     if(vis[p[i].v])ans=min(ans,d[p[i].v]);
                     if(!in[p[i].v])
                     {
                         in[p[i].v]=;
                         q.push(p[i].v);
                     }
                 }
             }
         }
 }
 int main()
 {
     //freopen("input.txt","r",stdin);
     //freopen("output.txt","w",stdout);
     std::ios::sync_with_stdio(false);
     while(scanf("%d%d%d",&n,&m,&t)!=EOF)
     {
         init();
          ans=inf;
         int u,v,w;
         f(i,,n)
         {
             scanf("%d%d%d",&u,&v,&w);
             addedge(u,v,w);
             addedge(v,u,w);
         }
         f(i,,m)scan(a[i]);
         f(i,,t)
         {
             scan(b);
             vis[b]=;
         }
         f(i,,m)
         {
             SPFA(a[i]);
         }
         pf("%d\n",ans);
     }
  }