Valid Bracket Sequence

Given a string s consisting solely of bracket characters: (), [], {}, and , determine whether the brackets are properly nested and matched. In other words, check whether for every opening bracket there is a corresponding closing bracket in the correct order.

The problem can be formally expressed as: $$ \text{isValid}(s) = \begin{cases} \text{True} & \text{if } s \text{ is a valid bracket sequence,} \\ \text{False} & \text{otherwise.} \end{cases} $$

Examples:

• Input: "([]){}" → Output: True
• Input: "([)]" → Output: False
• Input: "" → Output: True

inputFormat

The input is provided via standard input (stdin) as a single line containing the string s composed exclusively of the characters (), [], {}, and .

outputFormat

Output a single line to standard output (stdout) containing either True if the bracket sequence is valid or False if it is not.

([]){}

True