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 ()
.
A matching pair of brackets is not balanced if the set of brackets it encloses are not matched. For example, {[(])}
is not balanced because the contents in between {
and }
are not balanced. The pair of square brackets encloses a single, unbalanced opening bracket, (
, and the pair of parentheses encloses a single, unbalanced closing square bracket, ]
.
By this logic, we say a sequence of brackets is balanced if the following conditions are 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.
Given strings of brackets, determine whether each sequence of brackets is balanced. If a string is balanced, return YES
. Otherwise, return NO
.
Function Description
Complete the function isBalanced in the editor below.
isBalanced has the following parameter(s):
- string s: a string of brackets
Returns
- string: either
YES
orNO
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
- , where is the length of the sequence.
- All chracters in the sequences ∈ { {, }, (, ), [, ] }.
Output Format
For each string, return YES
or NO
.
Sample Input
STDIN Function ----- -------- 3 n = 3 {[()]} first s = '{[()]}' {[(])} second s = '{[(])}' {{[[(())]]}} third s ='{{[[(())]]}}'
Sample Output
YES
NO
YES
Explanation
- The string
{[()]}
meets both criteria for being a balanced string. - The string
{[(])}
is not balanced because the brackets enclosed by the matched pair{
and}
are not balanced:[(])
. - The string
{{[[(())]]}}
meets both criteria for being a balanced string.