Solution: Remove Invalid Parentheses
Explore how to apply backtracking to solve the problem of removing invalid parentheses from a string. This lesson guides you through counting invalid parentheses and using recursion to generate all valid expressions by selectively removing minimum invalid characters. Understand how to maintain balanced parentheses and handle different character types while ensuring unique results.
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Statement
You are given a string, s, that contains:
Lowercase English letters
Opening
'('and closing')'parentheses
A string is considered valid if:
All opening parentheses
'('are closed properly by a matching')'.The parentheses are in the correct order and nesting.
Letters can appear anywhere and do not affect validity.
Return all possible valid strings that can be formed by removing the minimum number of invalid parentheses. The answer must be a list of unique strings, in any order.
Constraints:
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