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Solution: Remove Invalid Parentheses

Explore how to use backtracking to generate all valid strings by removing the minimum number of invalid parentheses from a given string. Learn to track and balance parentheses, manage recursive calls, and ensure uniqueness in results with an efficient approach suitable for coding interviews.

Statement

You are given a string, s, that contains:

  • Lowercase English letters

  • Opening '(' and closing ')' parentheses

A string is considered valid if:

  1. All opening parentheses '(' are closed properly by a matching ')'.

  2. The parentheses are in the correct order and nesting.

  3. 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:

  • 1 ...