Language: C++

#include<cmath>
#include<cstdio>
#include<cstdlib>
#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;

const double eps = 1e-6;
int sgn(double x){
    if(abs(x) < eps) return 0;
    else return x > 0 ? 1 : - 1;
}
struct Point{
    double x, y;
    Point(){};
    Point(double x1, double y1){
        x = x1, y = y1;
    }
};
typedef Point Vector;

int n;
Point p[1024], s1, s2, news2, news1;
int v1, v2;
Point readp(){
    int x, y;
    scanf("%d%d",&x,&y);
    return Point(x, y);
}

Vector operator + (Vector a, Vector b){
    return Vector(a.x + b.x, a.y + b.y);
}
Vector operator - (Vector a, Vector b){
    return Vector(a.x - b.x, a.y - b.y);
}
double operator % (Vector a, Vector b){
    return a.x * b.y - a.y * b.x;
}
double operator * (Vector a, Vector b){
    return a.x * b.x + a.y * b.y;
}
Vector operator / (Vector a, double b){
    return Vector(a.x / b, a.y / b);
}
Vector operator * (Vector a, double b){
    return Vector(a.x * b, a.y * b);
}
bool operator == (Point a, Point b){
    return sgn(a.x - b.x) == 0 && sgn(a.y - b.y) == 0;
}
bool PoiOnSeg(Point p, Point p1, Point p2){
    if(sgn((p - p1) % (p - p2)) != 0) return false;
    if(sgn((p1 - p) * (p2 - p)) > 0) return false;
    else return true;
}
double Length(Vector v){
    return sqrt(v.x * v.x + v.y * v.y);
}
double Len2(Vector v){
    return v.x * v.x + v.y * v.y;
}
Vector Unitv(Vector v){
    return v / Length(v);
}

int findf(Point s1){
    int f = n + 10;
    for(int i = 0; i + 1 < n; i++){
        if(PoiOnSeg(s1, p[i], p[i + 1]))
        {
            f = min(f, i);
        }
    }
    return f;
}

double ans;
void maxtime(Point s1, double &maxt1, double &maxt2){
    maxt1 = 0;
    Point nowp = s1;
    int f = findf(s1);
    for(int i = f + 1; i < n; i++){
        maxt1 += Length(nowp - p[i]);
        nowp = p[i];
    }
    nowp = s1;
    maxt2 = 0;
    for(int i = f; i >= 0; i--){
        maxt2 += Length(nowp - p[i]);
        nowp = p[i];
    }
    
    maxt1 /= v1;
    maxt2 /= v1;
}

Point getto(Point s1, double t, int dir){
    double nowt = 0;
    Point nowp = s1;
    int f = findf(nowp);
    if(dir == 1)
    {
        for(int i = f + 1; i < n; i++){
            if(nowp == p[i]) continue;
            double needt = Length(nowp - p[i]) / v1;
            if(sgn(nowt + needt - t) >= 0){
                nowp = nowp + Unitv(p[i] - nowp) * (t - nowt) * v1;
                break;
            }
            else{
                nowt += needt;
                nowp = p[i];
            }
        }
    }
    else
    {
        for(int i = f; i >= 0; i--){
            if(nowp == p[i]) continue;
            double needt = Length(nowp - p[i]) / v1;
            if(sgn(nowt + needt - t) >= 0){
                nowp = nowp + Unitv((p[i] - nowp)) * (t - nowt) * v1;
                break;
            }
            else{
                nowt += needt;
                nowp = p[i];
            }
        }
    }
    return nowp;
}

bool PoiInCir(Point p, Point c, double r){
    return sgn(Len2(p - c) - r * r) <= 0;
}

double solve(Point sta, Point aim, double maxt, int dir){
    double l = 0.0, r = maxt, mid;
    int tt = 100;
    while(r - l > 1e-10 && tt--){
        mid = (l + r) * 0.5;
        Point p1 = getto(aim, mid, dir);
        if(PoiInCir(p1, sta, mid * v2)) r = mid;
        else l = mid;
    }
    return l;
}

double solve1(){
    double maxt1, maxt2, t1, t2;
    
    maxtime(s1, maxt1, maxt2);
    t1 = solve(s2, s1, maxt1, 1);
    if(sgn(t1 - maxt1) == 0) return 1e20;
    news2 = getto(s1, t1, 1);
    news1 = getto(s1, t1, 2);
    
    if(sgn(t1 - maxt2) >= 0) return t1;
    
    maxtime(news1, maxt1, maxt2);
    
    t2 = solve(news2, news1, maxt2, 2);
    
    return t1 + t2;
}

double solve2(){
    double maxt1, maxt2, t1, t2;
    
    maxtime(s1, maxt1, maxt2);
    t2 = solve(s2, s1, maxt2, 2);
    if(sgn(t2 - maxt2) == 0) return 1e20;
    news2 = getto(s1, t2, 2);
    news1 = getto(s1, t2, 1);
    
    if(sgn(t2 - maxt1) >= 0) return t2;
    
    maxtime(news1, maxt1, maxt2);
    
    t1 = solve(news2, news1, maxt1, 1);
    
    return t1 + t2;
}

int main(){
    scanf("%d",&n);
    for(int i = 0; i < n; i++){
        p[i] = readp();
        v.push_back(p[i]);
    }
    s1 = readp(); scanf("%d",&v1);
    s2 = readp(); scanf("%d",&v2);
    
    double maxt1, maxt2;
    maxtime(s1, maxt1, maxt2);
    
    double ans = min(solve1(), solve2());
    ans = min(ans, max(maxt1, maxt2));
    printf("%.10f\n", ans);
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:192:9: error: 'v' was not declared in this scope
  192 |         v.push_back(p[i]);
      |         ^