注意到「最大值与最小值的差」这一函数有单调性，上双指针即可。

#include <bits/stdc++.h>
using namespace std;
int a[200012];
int main()
{
    int n, k;
    cin >> n >> k;
    for (int i = 1; i <= n; i++)
        cin >> a[i];
    sort(a + 1, a + n + 1);
    int r = 1, ans = 1;
    for (int i = 1; i <= n - 1; i++)
    {
        while (r < n && a[r + 1] - a[i] <= k) r++;
        ans = max(ans, r - i + 1);
    }
    cout << ans << endl;
    return 0;
}