Balanced Brackets Coding | Dataford Interview Questions

JustAnswer's expert response composer accepts expressions containing nested grouping symbols and quoted text. Implement a validator that determines whether every bracket is correctly matched and nested, while ignoring bracket characters inside quoted strings.

Formal Specification

Given a string expression, return True if it is valid and False otherwise. Valid expressions contain matching pairs of (), [], and {}. Brackets must be properly nested. Text outside brackets is allowed. A quoted string begins and ends with either a single quote (') or double quote ("), and brackets inside quoted strings are ordinary characters. A backslash escapes the next character inside a quoted string. An unterminated quoted string makes the expression invalid.

The function must process the expression in one left-to-right pass without removing characters or using regular expressions.

Constraints

0 <= len(expression) <= 10^6
expression contains printable ASCII characters
Only (), [], and {} are structural brackets
A backslash escapes exactly the next character inside a quoted string

Function Signature

def has_balanced_brackets(expression):

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