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=0;
    mem(head,-1);
    mem(nxt,-1);
    mem(vis,0);
}
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,0);
        d[src]=0;
        queue<int>q;
        q.push(src);
        in[src]=1;
        while(!q.empty())
        {
            int now=q.front();
            q.pop();
            in[now]=0;
            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]=1;
                        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,1,n)
        {
            scanf("%d%d%d",&u,&v,&w);
            addedge(u,v,w);
            addedge(v,u,w);
        }
        f(i,1,m)scan(a[i]);
        f(i,1,t)
        {
            scan(b);
            vis[b]=1;
        }
        f(i,1,m)
        {
            SPFA(a[i]);
        }
        pf("%d
",ans);
    }
 }