2D Prefix Sum

[azurerazor]

Summary

2D prefix sum code

Submission Link/Screenshots

https://vjudge.net/solution/54612854/D6Wk7DLFARgewxmxhWWQ NOTE: Currently untested on rectangular grids.

Checklist

• [x] AC on at least 1 problem
• [x] Using tabs for indentation
• [x] Longest line at most 63 characters (with tab length 2)
• [x] Well documented

[azurerazor]

test on a rectangular grid lol

now tested on rectangular grids. @enwask

Also need a review of documentation just to make sure I can check off the last box fine