luogu P4779 【模板】单源最短路径（标准版）| dijkstra

寻找每一个点到原点的最小距离

#include<cstdio>
#include<queue>
using namespace std;
int val[200020],vis[200020],head[100010],nxt[200020],to[200020];
int n,m,s,k;
struct pot
{
    int x,dis;
    pot(int _x=0,int _dis=0):x(_x),dis(_dis){}
    friend bool operator < (pot a,pot b)
    {
        return a.dis>b.dis;
    }
};
priority_queue<pot> que;
void dijkstra()
{
    for(int i=1;i<=n;i++) dis[i]=2e9;
    que.push(pot(s,0));
    dis[s]=0;
    while(!que.empty())
    {
        pot now;
        now=que.top();
        que.pop();
        if(vis[now.x]) continue;
        vis[now.x]=true;
        for(int i=head[now.x];i;i=nxt[i])
        {
            if(dis[to[i]]>dis[now.x]+val[i])
            {
                dis[to[i]]=dis[now.x]+val[i];
                que.push(pot(to[i],dis[to[i]]));
            }
        }
    }
}