题解 | 小红关鸡

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

ll a[100005];

void solve()
{
    ll n, k;
    cin >> n >> k;
    for (ll i = 1; i <= n; i++)
    {
        cin >> a[i];
    }
    if (n == 0)
    {
        cout << 0;
        return;
    }
    if (n == 1)
    {
        if (a[1] <= k)
            cout << 1;
        else
            cout << 0;
        return;
    }

    sort(a + 1, a + n + 1);

    double ans = 0;
    ll dis = 0, cnt = 0;
    ll l = 1, r = 0;

    while (r <= n)
    {
        r++;
        cnt++;
        dis = a[r] - a[l];
        if (a[r]-a[l]<=k)
        {
            continue;
        }

        ans = max(ans, (cnt - 1) * 1.0 / n);

        while (dis > k)
        {
            l++, cnt--;
            dis = a[r] - a[l];
        }
    }

    cout << ans;
}

int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    solve();
    return 0;
}

先将坐标排序，然后开始滑动窗口