题解 | #万万没想到之抓捕孔连顺#

public class Main{
    public static int mod = 99997867;
    public static void main(String[] args){
        long count = 0;
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int d = sc.nextInt();
        int[] pos = new int[n];
        for (int i = 0; i < n; i++){
            pos[i] = sc.nextInt();
        }
        int left = 0;
        for (int right = 2; right < n; right++){
            while (pos[right] - pos[left] > d){
                left++;
            }
            long p = right - left;
            count += p * (p - 1) / 2;
        }
        System.out.println(count % mod);
    }
}