最大值减去最小值小于或等于num的子数组数量

链接
给定数组 arr 和整数 num，共返回有多少个子数组满足如下情况：
max(arr[i...j]) - min(arr[i...j]) <= num
max(arr[i...j])表示子数组arr[i...j]中的最大值，min[arr[i...j])表示子数组arr[i...j]中的最小值。

import java.util.*;

public class Main {

    private static int solve(int[] arr, int k) {

        int n = arr.length;

        int ret = 0;

        LinkedList<Integer> minQueue = new LinkedList<>();
        LinkedList<Integer> maxQueue = new LinkedList<>();

        int l = 0;
        for (int i = 0; i < n; ++i) {
            while (!minQueue.isEmpty() && arr[i] <= arr[minQueue.peekLast()]) {
                minQueue.pollLast();
            }
            minQueue.offerLast(i);

            while (!maxQueue.isEmpty() && arr[i] >= arr[maxQueue.peekLast()]) {
                maxQueue.pollLast();
            }
            maxQueue.offerLast(i);

            /**
             * 移动左指针到满足条件的位置
             */
            while (arr[maxQueue.peekFirst()] - arr[minQueue.peekFirst()] > k) {
                if (maxQueue.peekFirst() > minQueue.peekFirst()) {
                    l = minQueue.pollFirst() + 1;
                } else if (maxQueue.peekFirst() < minQueue.peekFirst()) {
                    l = maxQueue.pollFirst() + 1;
                }
            }

            ret += (i - l) + 1;
        }

        return ret;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while (in.hasNext()) {
            int n = in.nextInt();
            int k = in.nextInt();
            int[] arr = new int[n];
            for (int i = 0; i < n; ++i) {
                arr[i] = in.nextInt();
            }
            System.out.println(solve(arr, k));
        }
    }
}