balanceBracket.java

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.regex.*;

public class Solution {

    // Complete the isBalanced function below.
    static String isBalanced(String s) {

        Stack<Character> stack = new Stack<Character>();

        for(int i=0; i < s.length(); i++)
        {
            char currChar = s.charAt(i);
            if(currChar == '(' || currChar == '[' || currChar == '{')   // if string contains opening bracket push it to stack
            {
                stack.push(currChar);
            }
            if(currChar == ')' || currChar == '}' || currChar == ']')   // if string contains closing bracket
            {
                if(!stack.empty())                                      // cheack if stack is not empty
                {
                    if(currChar == ')' && stack.peek() != '(')          // cheack condition for matching pair
                    {   
                        return "NO";
                    }

                    if(currChar == '}' && stack.peek() != '{')          // cheack condition for matching pair
                    {   
                        return "NO";
                    }

                    if(currChar == ']' && stack.peek() != '[')           // cheack condition for matching pair
                    {   
                        return "NO";
                    }
                
                    stack.pop();
                }else{
                    return "NO";                                          // if stack is empty return NO
                }
            }
        }
        if(stack.empty())
        {
            return "YES";                                                 // everything stisfies return YES
        } 
        return "NO";
    }

    private static final Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) throws IOException {
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        int t = scanner.nextInt();
        scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");

        for (int tItr = 0; tItr < t; tItr++) {
            String s = scanner.nextLine();

            String result = isBalanced(s);

            bufferedWriter.write(result);
            bufferedWriter.newLine();
        }

        bufferedWriter.close();

        scanner.close();
    }
}