为什么

#include <bits/stdc++.h>
using namespace std;

double t[200005], v[200005];

int main() {
    int n;
    double s, e, v0;
    scanf("%d%lf%lf%lf", &n, &s, &e, &v0);
    if (e == s) {
        cout << 0 << '\n';
        return 0;
    }
    double ans = (v0 <= 1e-8) ? 1e100 : ((e - s) / v0);
    for (int i = 1; i <= n; i ++) {
        cin >> t[i] >> v[i];
        ans = min(ans, e / v[i] + t[i]);
    }
    printf("%lf\n", ans);
    return 0;
}

可以 AC，

#include <bits/stdc++.h>
using namespace std;

double t[200005], v[200005];

int main() {
    int n;
    double s, e, v0;
    cin >> n >> s >> e >> v0;
    if (e == s) {
        cout << 0 << '\n';
        return 0;
    }
    double ans = (v0 <= 1e-8) ? 1e100 : ((e - s) / v0);
    for (int i = 1; i <= n; i ++) {
        cin >> t[i] >> v[i];
        ans = min(ans, e / v[i] + t[i]);
    }
    cout << ans << '\n';
    return 0;
}

不行？