Parentheses pairing ({}[]()<>) issue

Question

I want to be able to pair up all parentheses in a string, if they aren\'t paired then then they get their index number and False. It seems like it is repeating some values over

Answer 1

First we will scan the string from left to right, and every time we see an opening parenthesis we push it to a stack, because we want the last opening parenthesis to be closed first. (Remember the FILO structure of a stack!) Then, when we see a closing parenthesis we check whether the last opened one is the corresponding closing match, by popping an element from the stack. If it’s a valid match, then we proceed forward, if not return false. Code: https://gist.github.com/i143code/51962bfb1bd5925f75007d4dcbcf7f55