feat: Add solution for Project Euler Problem 121 (#4261)
* Added solution for Project Euler problem 121
* Updated typing for 3.9
* updating DIRECTORY.md
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com> F
fpringle committed
89a43c81e50e0b5b46da78143a239967e198c1fa
Parent: 8f5f32b
Committed by GitHub <noreply@github.com>
on 3/20/2021, 5:59:48 AM