谁帮我看看为啥我能骗到 $60$ 分？

记录

#include <bits/stdc++.h>
#define int long long
#define double long double
using namespace std;
double x, p, q, t[100010];
int l = 1, r = 1e9, n;
signed main()
{
    cin >> n >> x >> p >> q;
    for (int i = 1; i <= n; i++)
    {
        cin >> t[i];
        t[0] += t[i];
    }
    while (l < r)
    {
        int mid = (l + r) / 2;
        if (mid * x * p / q + t[0] > mid * x)
            l = mid + 1;
        else
            r = mid;
    }
    cout << r;

    return 0;
}