【模板】迪杰斯特拉的优先队列优化

#include<iostream>#include<cstdio>#include<cstring>#include<algorithm>#include<queue>using namespace std;const int SIZE=100010;int head[SIZE],n,m,s,ecnt,dis[SIZE];bool vis[SIZE];struct node{    int id,w;};struct edge{    int v,nxt,dist;}e[SIZE];bool operator <(node a,node b){    return (a.w>b.w);}void add_edge(int from,int to,int dis){    e[++ecnt]=(edge){to,head[from],dis};    head[from]=ecnt;}void dijkstra(int u){    memset(dis,0x3f,sizeof(dis));    memset(vis,0,sizeof(vis));    priority_queue<node>q;    dis[u]=0;    q.push((node){u,0});    while(!q.empty())    {        node flag=q.top();        q.pop();        int v=flag.id;        if(vis[v]) continue;        vis[v]=1;        for(int i=head[v];i;i=e[i].nxt)        {            int to=e[i].v;            if(dis[to]>dis[v]+e[i].dist)            {                dis[to]=dis[v]+e[i].dist;                q.push((node){to,dis[to]});            }        }    }}int main(){    scanf("%d%d%d",&n,&m,&s);    for(int i=1,x,y,z;i<=m;i++)    {        scanf("%d%d%d",&x,&y,&z);        add_edge(x,y,z);        add_edge(y,x,z);    }    dijkstra(s);    for(int i=1;i<=n;i++)        printf("%d ",dis[i]);    return 0;}