Dijkstra 优先队列优化

#include <iostream>
#include <queue>
#include <vector>
using namespace std;
const int N=405;
struct rec
{
    int v,w;
};
vector<rec> edge[N*N];
int n,st,ed;
__int64 dis[N*N];
bool vis[N*N];
struct cmp
{
    bool operator()(int a,int b)
    {
        return dis[a]>dis[b];
    }
};
void Dijkstra()
{
    priority_queue<int,vector<int>,cmp> Q;  //
    memset(dis,-1,sizeof(dis));
    memset(vis,0,sizeof(vis));
    int i,u,v;
    Q.push(st);
    dis[st]=0;
    while(!Q.empty())
    {
        u=Q.top();
        Q.pop();
        vis[u]=0;
        if(u==ed)
            break;
        for(i=0;i<edge[u].size();i++)
        {
            v=edge[u][i].v;
            if(dis[v]==-1 || dis[v]>dis[u]+edge[u][i].w)
            {
                dis[v]=dis[u]+edge[u][i].w;
                if(!vis[v])
                {
                    vis[v]=1;
                    Q.push(v);
                }
            }
        }
    }
} 

1

struct edge {int to,cost;};
typedef pair<int,int> P; //first是最短距离，second是顶点的编号
int V;//顶点个数
vector<edge> G[MAXV];
int d[MAXV];

void dijkstra(int s)
{
    priority_queue<P,vector<P>,greater<P> > que;
    memset(d,INF,sizeof d);
    d[s] = 0;
    que.push(P(0,s)); //把起点推入队列
    while(!que.empty())
    {
        P p = que.top(); que.pop();
        int v = p.second; //顶点的编号
        if (d[v] < p.first) continue;
        for(int i = 0; i < G[v].size(); i++)
        {
            edge e = G[v][i];
            if (d[e.to] > d[v] + e.cost)
            {
                d[e.to] = d[v] + e.cost;
                que.push(P(d[e.to],e.to));
            }
        }
    }
}

2