Fix Travis CI slow build on Project Euler Solution job (#3262)

* Fix Travis CI long run for validate_solutions

* updating DIRECTORY.md

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

Dhruv committed 5y ago

34d63d51553e624ed3f4a6560c0e6b241ba2587c

Parent: ca2d269

Committed by GitHub <noreply@github.com> on 10/13/2020, 5:13:40 PM