Sliding Window Technique

Sliding window technique is useful for solving problems in array or string, especially it is considered as a technique that could reduce the time complexity from O(n²) to O(n).

There are two types of sliding window:

1. Fixed window length k: the length of the window is fixed and it asks you to find something in the window such as the maximum sum of all windows, the maximum or median number of each window. Usually we need kind of variables to maintain the state of the window, some are as simple as a integer or it could be as complicated as some advanced data…