Coding questions · Intuit

Validate bracket sequence

This question evaluates understanding of bracket matching and string parsing, testing competency with basic data structures and algorithmic reasoning such as stack-based matching and correct handling of nested delimiters.

Given a string s containing only the characters (, ), [, ], {, and }, determine whether the brackets are properly matched.

A string is valid if:

Every opening bracket is closed by a bracket of the same type.
Brackets are closed in the correct order.
No closing bracket appears without a matching earlier opening bracket.

Return true if the string is valid and false otherwise.

Example 1:

Input: s = "()[]{}"
Output: true

Example 2:

Input: s = "([)]"
Output: false

Example 3:

Input: s = "{[]}"
Output: true

Be prepared to write and run a few test cases, including edge cases such as the empty string.

Validate Bracket Sequence

Constraints

0 <= len(s) <= 100000
s contains only the characters '(', ')', '[', ']', '{', and '}'

Hints

Use a stack to keep track of opening brackets as you scan the string from left to right.
When you see a closing bracket, it must match the most recent unmatched opening bracket.