dijkstra 优先队列最短路模板

const int inf=1000000000;
const int maxn=300010;
int dist[maxn],head[maxn],tol,m,n;
struct Edge
{
        int to,next,val;
}edge[10*maxn];
void add(int u,int v,int w)
{
        edge[tol].to=v;
        edge[tol].next=head[u];
        edge[tol].val=w;
        head[u]=tol++;
}
struct Node
{
        int id,dist;
        Node(int a=0,int b=0):id(a),dist(b){}
        bool operator < (const Node &b) const
        {
                return dist>b.dist;
        }
};
void fun(int st)
{
        int i,j,u,v;
        priority_queue<Node> q;
        q.push(Node(st,0));
        for(i=1;i<=n;i++)dist[i]=inf;
        dist[st]=0;
        while(!q.empty())
        {
                Node ret=q.top();q.pop();
                u=ret.id;
                if(dist[u]<ret.dist)continue;
                for(i=head[u];i!=-1;i=edge[i].next)
                {
                        v=edge[i].to;
                        if(dist[v]>dist[u]+edge[i].val)
                        {
                                dist[v]=dist[u]+edge[i].val;
                                q.push(Node(v,dist[v]));
                        }
                }
        }
}