Valid Parentheses Checker
Given a string s containing only '(' , ')' , '{' , '}' , '[' , ']', return True if valid: opens must be closed by same type and in correct order.
Test Cases
"()"→ True"[]{}"→ True"["→ False"({})"→ True"(((((((())))))))"→ True"([)]"→ False"]"→ False""→ True"((("→ False"())"→ False
Classic stack validation: push opening brackets, on closing bracket check top matches type, otherwise invalid; finally stack must be empty. Edge cases: empty string is valid, premature closing, leftover opens. Complexity is linear time and linear space in worst case.
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