Brace Matching Coding | Dataford Interview Questions

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Problem

PagerDuty Event Orchestration expressions may contain parentheses, square brackets, and curly braces. Given an expression string, determine whether every bracket is properly closed and correctly nested.

A string is valid when:

Every opening bracket has a matching closing bracket of the same type.
Brackets close in last-in, first-out order.
Non-bracket characters, such as letters, digits, spaces, and operators, are ignored.

Return True if the expression is valid. Otherwise, return False.

Formal Specification

Implement is_valid_brackets(expression), which accepts a string and returns a Boolean. The input contains printable ASCII characters. An empty string is valid because it contains no unmatched brackets.

Constraints

0 <= len(expression) <= 10^4
Only (), [], and {} are treated as brackets.
Non-bracket characters may appear anywhere and must be ignored.
The input contains printable ASCII characters.

Function Signature

def is_valid_brackets(expression):