Bracket matching using stack

Bracket matching using stack. A bracket is considered to be any one of the following characters: (, ), {, }, [, or ].

Two brackets are considered to be a matched pair if the an opening bracket (i.e., (, [, or {) occurs to the left of a closing bracket (i.e., ), ], or }) of the exact same type. There are three types of matched pairs of brackets: [], {}, and ().

If the set of brackets match then it is a matching pair. For example, {[(])} is not balanced because the contents in between { and } are not balanced. The pair of square brackets enclose a single, unbalanced opening bracket, (, and the pair of parentheses encloses a single, unbalanced closing square bracket, ].

To call it balance following conditions is met:

• It contains no unmatched brackets.
• The subset of brackets enclosed within the confines of a matched pair of brackets is also a matched pair of brackets.

Determine if each sequence is balanced. If a string is balanced, return YES. Otherwise, return NO.

Function Description

Complete the function isBalanced in the editor below. It must return a string: YES if the sequence is balanced or NO if it is not.

isBalanced has the following parameter(s):

• s: a string of brackets

Input Format

The first line contains a single integer , the number of strings.
Each of the next  lines contains a single string , a sequence of brackets.

Constraints

• 1 <= n <= 10^3
• |s| is between 1 to 10^3, where |s| is the length of the sequence.
• All chracters in the sequences ∈ { {, }, (, ), [, ] }.

Output Format

For each string, return YES or NO.

Sample Input

3
{[()]}
{[(])}
{{[[(())]]}}

Sample Output

YES
NO
YES

Explanation

1. The string {[()]} meets both criteria for being a balanced string, so we print YES on a new line.
2. The string {[(])} is not balanced because the brackets enclosed by the matched pair { and } are not balanced: [(]).
3. The string {{[[(())]]}} meets both criteria for being a balanced string, so we print YES on a new line.

Problem description is got from the hackerank.

The solution in C++ takes O(n) complexity using stack data structure is as follows:

Also view other algorithms here.