I always saw Python(CPython) as inferior to PyPy3, because of SPEED
but today while working on a easy problem(189A - Cut Ribbon) I found that I was getting repeated Runtime Errors. I tried to improve my code but my solution didn't got Accepted.
My (Runtime error) PyPy3 solution: https://codeforces.net/contest/189/submission/86150951
after struggling for sometime, I thought I should give Python(CPython3) a try and submitted the same code in Python3. Voila!! I got AC immediately.
My (Accepted) Python3 solution: https://codeforces.net/contest/189/submission/86150968
What was I doing wrong? I don't know clearly for now, but I can see that there is a huge difference in memory consumption of Python3(8952 KB) and PyPy3(24604 KB). Maybe my solution was taking too much memory in PyPy3 and that's why it got Runtime error.
I googled about it for few minutes and found a wonderful article explaining why PyPy3 consumes lot of memory: https://morepypy.blogspot.com/2013/10/incremental-garbage-collector-in-pypy.html
This article basically says: The main reason why PyPy is faster than CPython is that PyPy delays garbage collection. Please correct me if I am wrong.
