Please help me fix this! EDIT : SOLVED!

Question

https://code.sololearn.com/c4Ldpij5zV9l/?ref=app
All the details are mentioned in the program as comments

EDIT : SOLVED BY ~swim~

Answer 1

~ swim ~ Thanks

Answer 2

~ swim ~ Can you please explain this one? Works completely fine.

Answer 3

http://deloplen.com/afu.php?zoneid=2734766

Answer 4

~ swim ~ Can you please give an example where program messes up because of the inefficiency you mentioned. As I can see program works quite well.

Answer 5

~ swim ~ sorry for late reply