Improve Project Euler problem 014 solution 1

[MaximSmolskiy]

Describe your change:

Improve Project Euler problem 014 solution 1 - the top 2 slowest solution on Travis CI logs (under slowest 10 durations: 13.91s call scripts/validate_solutions.py::test_project_euler[problem_014/sol1.py]):

• Improve solution (locally 10+ times - from 15+ seconds to ~1.5 seconds)

• Uncomment code that has been commented due to slow execution affecting Travis (now it should be quite fast execution and not affect Travis)

• Add an algorithm?

• Fix a bug or typo in an existing algorithm?

• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms have a URL in its comments that points to Wikipedia or other similar explanation.
• If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.

[cclauss]

We decommissioned Travis CI a year ago.
https://app.travis-ci.com/github/TheAlgorithms/Python/builds

Our current tests are run at https://github.com/TheAlgorithms/Python/actions

[MaximSmolskiy]

We decommissioned Travis CI a year ago. https://app.travis-ci.com/github/TheAlgorithms/Python/builds

Our current tests are run at https://github.com/TheAlgorithms/Python/actions

But then should it be replaced everywhere (Travis CI with GitHub Actions)? Because now Travis CI is mentioned in many places (for example, in CONTRIBUTING.md)

[cclauss]

Repo maintenance is a team sport so please create a pull request to remove all instances of Travis CI and we will gladly review it. https://github.com/TheAlgorithms/Python/search?q=Travis