Katkat
Back

Remove minimum invalid mixed brackets

MetaSoftware Engineer · Technical Screen
HardSoftware EngineerTechnical ScreenCoding & Algorithms

Last updated

This Coding & Algorithms problem evaluates string-processing and bracket-matching skills, specifically understanding of stack-based parsing, handling multiple bracket types, and minimizing removals while preserving non-bracket characters.

Given a string s containing letters and bracket characters from the set (), [], {}, remove the minimum number of bracket characters so that the resulting string has properly matched and properly nested brackets.

Rules:

  • Matching must respect types: ( matches ), [ matches ], { matches }.
  • Brackets must be properly nested (e.g., ([)] is invalid).
  • Keep all non-bracket characters in their original order.
  • If multiple valid answers exist, return any one.

Example:

  • Input: ([{ab)
  • Output: (ab) (remove [ and { to make the remaining brackets valid).