这题就是k短路的一个模板题，恶心的是题面没说每条路径不能有重复点
题面链接

代码

#include<stdio.h>
#include<algorithm>
#include<math.h>
#include<bitset>
#include<bits/stdc++.h>
using namespace std;
#include<queue>
const int inf=1e9;
#define ll long long
#define maxn 505
int n,m;
struct node
{
    int to; double w;
    friend bool operator<(node a,node b)
    {
        return a.w>b.w;
    }
};
struct nd
{
    int x,y;
}a[maxn];
struct nd1
{
    int x;double y;


};
double h[maxn];
vector<nd1>e[maxn];
double js(int i,int j)
{
    int x=(a[i].x-a[j].x)*(a[i].x-a[j].x)+(a[i].y-a[j].y)*(a[i].y-a[j].y);
    return sqrt(x);
}
priority_queue<node>q;int vis[maxn];
void dijk1()
{
    for(int i=1;i<=n;i++) h[i]=inf;
    q.push({n,0});h[n]=0;
    while(!q.empty())
    {
        int u=q.top().to;q.pop();
        if(vis[u]==1) continue;
        vis[u]=1;
        //printf("h[%d]=%.4f\n",u,h[u]);
        for(nd1 i:e[u])
        {
            int v=i.x;double w=i.y;
            if(h[v]>h[u]+w)
            {
                h[v]=h[u]+w;
                //printf(" w=%.4f h[%d]=%.4f\n",w,v,h[v]);
                if(vis[v]==0)
                {
                    q.push({v,h[v]});
                }
            }
        }
    }
}
struct node1
{
    int to;double w;
    bitset<maxn>vis;
    friend bool operator<(node1 a,node1 b)
    {
        return a.w+(h[a.to])>b.w+(h[b.to]);
    }
};
priority_queue<node1>q1;
void astar()
{
    if(h[n]==inf)
    {
        printf("-1\n");
        return ;
    }
    bitset<maxn>vis0;
    vis0[1]=1;
    q1.push({1,0.0,vis0});
    int f=0;double ans=0.0;
    while(!q1.empty())
    {
        int u=q1.top().to;double s=q1.top().w;
        bitset<maxn>vis1(q1.top().vis);

        q1.pop();
        //printf("u=%d s=%.4f\n",u,s);
        //for(int i=1;i<=n;i++) printf("vis1[%d]=%d\n",i,(int)vis1[i]);
        if(u==n)
        {
            f++;
            if(f==2)
            {
                ans=s;
                break;
            }
        }
        for(nd1 i:e[u])
        {
            int v=i.x;double w=(i.y);
            if(vis1[v]==1) continue;
            bitset<maxn>vis2(vis1);
            vis2[v]=1;
            //printf(" v=%d w=%.4f\n",v,w);
            q1.push({v,s+w,vis2});
        }
    }
    if(f!=2) printf("-1\n");
    else printf("%.2f\n",ans);
}
int main()
{
	scanf("%d %d",&n,&m);
	for(int i=1;i<=n;i++)
    {
        scanf("%d %d",&a[i].x,&a[i].y);
    }
    for(int i=1;i<=m;i++)
    {
        int u,v;
        scanf("%d %d",&u,&v);
        e[u].push_back({v,js(u,v)});
        e[v].push_back({u,js(u,v)});
    }
    dijk1();
    astar();
}