Dijkstra（迪杰斯特拉）模板

struct Edge{
    int from,to,dist;
    Edge(int u, int v,int d): from(u),to(v),dist(d){}
};

struct HeapNode{
    int d, u;
    bool operator <(const HeapNode& rhs) const {
    return d> rhs.d;
    }
};

struct Dijkstra{
    int n,m;
    vector<Edge> edges;
    vector<int > G[maxn];
    bool done[maxn];///是否标记过
    int d[maxn];///s到各个点的距离
    int p[maxn];///最短路的上一条弧

    void init(int n){
        this->n=n;
        for(int i=0;i<n;i++) G[i].clear();
        edges.clear();
    }

    void AddEdge(int from,int to,int dist){
        edges.push_back(Edge(from,to,dist));
        m = edges.size();
        G[from].push_back(m-1);
    }

    void dijkstra(int s){
        priority_queue<HeapNode> Q;
        for(int i = 0; i<n; i++) d[i]=INF;
        d[s] = 0;
        memset(done, 0, sizeof(done));
        Q.push((HeapNode){0,s});
        while(!Q.empty()){
            HeapNode x = Q.top();Q.pop();
            int u = x.u;
            if(done[u]) continue;
            done[u] = true;
            for(int i = 0;i < G[u].size();i++){
                Edge& e = edges[G[u][i]];
                if(d[e.to]>d[u] + e.dist){
                    d[e.to] = d[u] + e.dist;
                    p[e.to] = G[u][i];
                    Q.push((HeapNode){d[e.to], e.to});
                }
            }
        }
    }
};