kotlin-coding-challenges

Valid parentheses

Instructions

Given a string containing only the characters (, ), {, }, [ and ], implement a function to determine if the input string is valid. An input string is valid if:

• Open brackets must be closed by the same type of bracket.
• Open brackets must be closed in the correct order.
• Every close bracket has a corresponding open bracket of the same type.

Challenge

Solution

Examples

isValidParentheses("()") // true

isValidParentheses("()[]{}") // true

isValidParentheses("(]") // false - '(' must be closed by ')' not ']'

isValidParentheses("([)]") // false - brackets are interleaved, not closed in correct order

isValidParentheses("{[]}") // true - properly nested brackets

Hints

Hint 1

Use a stack.

Hint 2

Push open brackets to the stack. For each close bracket pop the stack and check that popped bracket matches.

This site is open source. Improve this page.