题解 | #万万没想到之抓捕孔连顺#

import java.io.InputStreamReader;
import java.io.BufferedReader;
import java.io.IOException;

public class Main{
    public static void main(String[] args) throws IOException{
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String str = reader.readLine();
        String[] splits = str.split(" ");
        int n = Integer.parseInt(splits[0]);
        int d = Integer.parseInt(splits[1]);
        str = reader.readLine();
        splits = str.split(" ");
        int[] arr = new int[n];
        int begin = 0, end = 0;
        long res = 0;
        for(; end < n; end++){
            arr[end] = Integer.parseInt(splits[end]);
            if(arr[end] - arr[begin] > d){
                while(arr[end] - arr[begin] > d){
                    res += (long)(end - begin - 1) * (end - begin - 2) / 2;
                    begin++;
                }
            }
        }
        for (; begin <= n-3; begin++) {
            res += (long)(end - begin - 1) * (end - begin - 2) / 2;
        }
        res %= 99997867;
        System.out.println(res);
    }
}