How should I practice Valid Parentheses?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Qualys onsite interview problems in FastPrep.

Is Valid Parentheses associated with Qualys?

FastPrep tags this as a Qualys onsite interview coding practice problem when the problem catalog has that company and stage context.

Valid Parentheses

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Problem statement

Given a string s containing only ()[]{}, determine whether its brackets are balanced. Every closing bracket must match the most recent unmatched opening bracket of the same type, and every opening bracket must be closed.

For this exercise, assume the empty string is valid. Return a boolean.

Function

validParentheses(s: String) → boolean

Examples

Example 1

s = "([]){}"return = true

Each pair has the correct type, and the square brackets close before their enclosing parentheses.

Example 2

s = "([)]"return = false

The first closing parenthesis encounters an unmatched opening square bracket, so the nesting is invalid.

Constraints

For this exercise, assume 0 <= s.length <= 10^5.
Every character is one of ( ) [ ] { }.