Binary Classification without machine learning tools
How about implementing one of the most basic binary classifiers by hand without any libraries, Logistic Regression?
Here is the explanation of the Logistic Regression in subtle terms:

https://www.youtube.com/watch?v=6tByJTacCOc&amp;index=6&amp;list=PLBAGcD3siRDguyYYzhVwZ3tLvOyyG5k6K

Here is the description of writing a simplified version of a binary classifier in Python, which will take a few buckets of lines in the vectorized form:

https://www.youtube.com/watch?v=ERIFzbTdIm0&amp;index=14&amp;list=PLBAGcD3siRDguyYYzhVwZ3tLvOyyG5k6K

If you feel uncomfortable with the implementation or confused about something, I'm sure that if you watch the videos in between the two that I provide, you will be able to easily write the algorithm that the video describes. I hope I could help; if you are not happy with the offered solution, I will be around for alternatives. Have fun.