URAL 1205 By the Underground or by Foot?（SPFA）

#include <iostream>
#include <cstring>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <time.h>
#include <string>
#include <map>
#include <stack>
#include <vector>
#include <set>
#include <queue>
#define inf 0x3f3f3f3f
#define mod 10000
typedef long long ll;
using namespace std;
const int N=205;
const int M=100005;
int n,m,k=0;
double a,b;
int vis[N],pre[N];
double w[N][N],d[N];
char str[20];
bool flag=false;
struct man{
    double x,y;
}point[N];
void spfa()
{
    d[0]=0;
    vis[0]=1;
    queue<int>q;
    q.push(0);
    while(!q.empty()){
        int t=q.front();q.pop();
        vis[t]=0;
        for(int i=0;i<=n+1;i++){
            if(d[i]>d[t]+w[t][i]){
                d[i]=d[t]+w[t][i];
                pre[i]=t;
                if(!vis[i])q.push(i),vis[i]=1;
            }
        }
    }
}
int main() {
    for(int i=0;i<N;i++){
        d[i]=10000000;
        for(int j=0;j<N;j++){
            w[i][j]=10000000;
        }
    }
    scanf("%lf%lf",&a,&b);
    scanf("%d",&n);
    int u,v;

    for(int i=1;i<=n;i++){
        scanf("%lf%lf",&point[i].x,&point[i].y);
    }
    while(~scanf("%d%d",&u,&v)&&u&&v){
        double s=sqrt((point[u].x-point[v].x)*(point[u].x-point[v].x)+(point[u].y-point[v].y)*(point[u].y-point[v].y));
        w[u][v]=w[v][u]=s/b;
    }
    scanf("%lf%lf%lf%lf",&point[0].x,&point[0].y,&point[n+1].x,&point[n+1].y);
    for(int i=0;i<=n+1;i++){
        for(int j=i+1;j<=n+1;j++){
            if(w[i][j]<10000000)continue;
            double s=sqrt((point[i].x-point[j].x)*(point[i].x-point[j].x)+(point[i].y-point[j].y)*(point[i].y-point[j].y));
            w[i][j]=w[i][j]=s/a;
        }
    }
    spfa();
    printf("%.7lf\n",d[n+1]);
    stack<int>p;
    for(int i=n+1;pre[i];i=pre[i]){
        p.push(pre[i]);
    }
    printf("%d",p.size());
    while(!p.empty())printf(" %d",p.top()),p.pop();
    return 0;
}