Sliding Window Maxima

Problem Statement : 
        Given an array of size n and window of size k (k < n) , find the maximum element in each contagious array of size k(also can be called as window) .

Leetcode:
239. Sliding Window Maximum
https://leetcode.com/problems/sliding-window-maximum/


Solution : 

There are multiple approaches to solve this problem, we will be solving the problem with the help of deque(double ended queue). The brute force approach would take O(n * k) time complexity as for each n , you will have to traverse next k elements.

Below is the implementation with the help of Deque, important thing to note here is that
i. all elements which are getting out of the window range needs to be removed and
ii. if there is a new larger incoming element coming in as part of new item, remove all smaller elements in the deque.


Below is the code implementation :

Please post comments and suggestions.
Happy Coding !! :)