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. 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
- , where 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
- The string
{[()]}
meets both criteria for being a balanced string, so we printYES
on a new line. - 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, so we printYES
on a new line.
쉽게 생각하면 { 와 [ 와 ( 에 대한 가중치? 계산을 해서 하나씩 더하고 빼고 하면 되겠지만, 중요한건 Balance 를 맞춰야만 "YES"가 된다는 것이다.
문제는 의외로 쉽게 풀 수 있다.
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