Dijkstra 优先队列 刘汝佳模板

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const int INF = 2147483647;
const int maxn = 1e3+3;
struct Edge{
    int from,to,dist;
    Edge(int u = 0,int v = 0,int w = 0):from(u),to(v),dist(w) {}
};
struct HeapNode{
    int d,u;
    bool operator < (const HeapNode & rhs) const {
        return d > rhs.d;
    }
    HeapNode(int d = 0,int u = 0):d(d),u(u) {}
};

struct Dijkstra{
    int n,m;
    vector<Edge> edges;
    vector<int> G[maxn];
    bool done[maxn];
    int d[maxn];
    int p[maxn];

    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));
                }
            }
        }
    }
};