Search⌘ K
AI Features
Home
Courses
Grokking the Coding Interview Patterns in C++

Solution: Remove Invalid Parentheses

Explore a backtracking algorithm to remove invalid parentheses from a string by recursively generating all valid combinations. Understand how to track removals and maintain balance to return unique valid expressions.

We'll cover the following...

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≤ ...