1129. 热浪

最短路裸题

const int N=2510;
vector<PII> g[N];
int dist[N];
bool vis[N];
int n,m,s,e;

void dijkstra()
{
    memset(dist,0x3f,sizeof dist);
    priority_queue<PII,vector<PII>,greater<PII> > heap;
    heap.push({0,s});
    dist[s]=0;

    while(heap.size())
    {
        int t=heap.top().second;
        heap.pop();
        
        if(vis[t]) continue;
        vis[t]=true;

        for(int i=0;i<g[t].size();i++)
        {
            int j=g[t][i].fi,w=g[t][i].se;
            if(dist[j] > dist[t] + w)
            {
                dist[j]=dist[t]+w;
                heap.push({dist[j],j});
            }
        }
    }
}

int main()
{
    cin>>n>>m>>s>>e;

    while(m--)
    {
        int a,b,c;
        cin>>a>>b>>c;
        g[a].pb({b,c});
        g[b].pb({a,c});
    }

    dijkstra();
    cout<<dist[n]<<endl;
    //system("pause");
}