Monotonic increasing - stack

 骨骼面试有一类比较Tricky的题目，即单调队列 Monotonic Queue / 单调栈 Monotonic Stack

通过单调队列，可以把复杂度降到O(n)，主要覆盖Stack, Sliding Window, Two Pointers, Linked List/Queue, HashTable/HashMap等算法和数据结构，分类参考主贴

https://www.1point3acres.com/bbs/thread-649468-1-1.html

6个月内
LC42. Trapping Rain Water
LC84. Largest Rectangle in Histogram (单调递增栈)
LC122. Best Time to Buy and Sell Stock II   
LC239. Sliding Window Maximum (有界最大值单调递减栈)
LC496. Next Greater Element I
LC862. Shortest Subarray with Sum at Least K (单调递增栈)
LC1438. Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit

LC907. Sum of Subarray Minimums, 
LC1019. Next Greater Node In Linked List,