CDOJ Find the Fastest Server （SPFA）

原题地址：http://acm.uestc.edu.cn/#/problem/show/702

 

题意

略

 

题解

 

#include<bits/stdc++.h>

#define clr(x) memset(x,0,sizeof(x))

using namespace std;
typedef long long LL;

struct edge{int to,cost;};

const int maxn=1e5;
const int inf=1e9;

int S[maxn+5];
int dist[maxn+5];
int query[maxn+5];
int vis[maxn+5];

queue <int> Q;
vector <edge> G[maxn+5];

int main(void)
{
    #ifdef ex
    freopen ("in.txt","r",stdin);
    //freopen ("out.txt","w",stdout);
    #endif

    int T;
    int n,m,q,k;
    int u,v,w;

    scanf("%d",&T);
    while (T--)
    {
        fill(dist,dist+sizeof(dist)/sizeof(int),inf);
        clr(vis);
        for (int i=1;i<=maxn;++i) G[i].clear();

        scanf("%d%d",&n,&m);
        for (int i=1;i<=m;++i)
        {
            scanf("%d%d%d",&u,&v,&w);
            G[u].push_back((edge){v,w});
            G[v].push_back((edge){u,w});
        }

        scanf("%d",&k);
        for (int i=1;i<=k;++i)
        {
            scanf("%d",&S[i]);
        }

        scanf("%d",&q);
        for (int i=1;i<=q;++i)
        {
            scanf("%d",&query[i]);
        }

        for (int i=1;i<=k;++i)
        {
            Q.push(S[i]);
            dist[S[i]]=0;
            vis[S[i]]=1;
        }

        while (!Q.empty())
        {
            int x=Q.front();
            Q.pop();
            vis[x]=0;

            for (int i=0;i<G[x].size();++i)
            {
                edge& e=G[x][i];
                if (dist[x]<inf && dist[e.to]>e.cost+dist[x])
                {
                    dist[e.to]=e.cost+dist[x];
                    if (!vis[e.to])
                    {
                        Q.push(e.to);
                        vis[e.to]=1;
                    }
                }
            }
        }

        for (int i=1;i<=q;++i)
        {
            if (dist[query[i]]<inf)
                printf("%d\n",dist[query[i]]);
            else
                printf("-1\n");
            //printf("%d\n",dist[i]);
        }

        printf("\n");
    }
}