Plot a heatmap coverage using seaborn

[rdancer]

https://towardsdatascience.com/create-githubs-style-contributions-plot-for-your-time-series-data-79df84ec93da

[rdancer]

There are as of today ~2.5k problems, so a square 50-a-side at 5px-a-side would be about 250x250px.

Something to look like the github heatmap or leetcode heatmap, but not ordered as a year with 365 cells, but the whole problem set with 2,500+ cells (i.e. 7x larger as of today, larger still as they add more and more problems)

Inspiration: