Practice: Balanced Brackets
A famous stack problem: is every opening bracket closed in the right order? "(a[b]{c})" is balanced; "(]" and "(()" are not.
The idea: push each opening bracket on a stack. When you meet a closing bracket, the top of the stack must be its matching opener; pop it. At the end the stack must be empty.
Examplepython
Quick check
At the end of a balanced check, what must be true of the stack?
Your turn: write the code
Write valid_parens(text) for round brackets only: return True if every ( has a matching ) in order. Print it for the three strings, one per line.
Finish the quick check (and any code exercise) to complete this lesson, or mark it done yourself.
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