Balanced Parentheses

Function Name: isBalanced

Description

Write a function that takes a string containing only '(', ')', '{', '}', '[' and ']', determines if the input string is valid. An input string is valid if:

1. Open brackets must be closed by the same type of brackets.

2. Open brackets must be closed in the correct order.

3. An empty string is considered balanced.

Requirements

• The function must be named 'isBalanced'.
• The 'isBalanced' function must take a single parameter: a string containing only the characters: '(', ')', '{', '}', '[' and ']'.
• The function must return a boolean value: true if the string is balanced, false otherwise.
• Do not use regular expressions to solve this challenge.
• Function should run in O(n) time, where n is the length of the string.

Examples

Example 1: isBalanced('(){}[]') should return true.Example 2: isBalanced('([)]') should return false.Example 3: isBalanced('{[()]}') should return true.Example 4: isBalanced('') should return true.Example 5: isBalanced('({[]}()') should return false.

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