关于链式前向星。

一些代码

理解

#include<bits/stdc++.h>
using namespace std;
//优先队列优化的链式前向星
const int maxn=1000;
const int INF=0x3fffffff;
struct Edge{
    int from, to, dist;
    Edge(int u, int v, int d):from(u),to(v),dist(d){}
};
struct HeapNode{
    int u, d;
    HeapNode(int u, int d):u(u),d(d){}
    bool operator < (const HeapNode & r) const {
        return d>r.d;
    }
};
struct Dijkstra{
    int n, m;
    vector<int>  G[maxn];
    vector<Edge> edges;
    int dis[maxn];
    int pre[maxn];
    int   v[maxn];
    void AddEdge(int u, int v, int d){
        edges.push_back(Edge(u, v, d));
        G[u].push_back(edges.size()-1);
    }
    void init(int v_size){
        n=v_size;
        edges.clear();
        for(int i=0; i<n; i++)    G[i].clear();
        memset(pre, 0, sizeof(pre));
    }
    void dijkstra(int s){
        for(int i=0; i<n; i++)    dis[i]=INF;
        dis[s]=0;
        memset(v, 0, sizeof(v));
        priority_queue<HeapNode> Q;
        Q.push(HeapNode(s, 0));
        while(!Q.empty()){
            HeapNode t=Q.top();
            Q.pop();
            int x=t.u;
            if(v[x])    continue;
            v[x]=1;
            for(int k=0; k<G[x].size(); k++){
                Edge & e = edges[G[x][k]];
                if(dis[x]+e.dist<dis[e.to]){
                    dis[e.to]=dis[x]+e.dist;
                    pre[e.to]=x;
                    Q.push(HeapNode(e.to, dis[e.to]));
                }
            }
        }
    }
};
int main(){
    int u, v, d; 
    Dijkstra a;
    a.init(10);
    while(){
        cin>>u>>v>>d;
        a.AddEdge(u, v, d);    
    }
    a.dijkstra(1);
    cout<<a.dis[5]<<endl;
    return 0;
}