have you been able to solve it?

Thanks for your help. I posted my solution because no one didn't comment on my first comment.

I have solved it and passes all test but i don't know why I can't sbmit my solution.

does one line of code has effect on time complexity

i don't know where some people get their ideas from. I get jealous when i see some people's code

my code is similar to yours but i use set to remove the duplicates

ok

you are right

it is for readability

what does "found" do in your solution

the only difference between the list and the set is that, the set doesn't stores duplicate but the list does

can you please explain your code to me?

thank you for making me to understand the problem