Balanced Brackets

Balanced Brackets

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;
import java.util.regex.*;
import java.util.stream.*;
import static java.util.stream.Collectors.joining;
import static java.util.stream.Collectors.toList;

class Result {

    /*
     * Complete the 'isBalanced' function below.
     *
     * The function is expected to return a STRING.
     * The function accepts STRING s as parameter.
     */

    public static String isBalanced(String s) {
    // Write your code here
Stack<Character> stack = new Stack<Character>();
for(int i = 0; i < s.length(); i++){
    if("{([".contains(s.charAt(i)+"")) stack.push(s.charAt(i));
    else if(s.charAt(i) == ']'){
        if(stack.isEmpty()) return "NO";
        if(stack.peek() != '[') return "NO";
        stack.pop();
                }
    else if(s.charAt(i) == '}'){
        if(stack.isEmpty()) return "NO";
        if(stack.peek() != '{') return "NO";
        stack.pop();
                }
    else if(s.charAt(i) == ')'){
        if(stack.isEmpty()) return "NO";
        if(stack.peek() != '(') return "NO";
        stack.pop();
                }
}
if(!stack.isEmpty()) return "NO";
return "YES";

    }

}

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

        int t = Integer.parseInt(bufferedReader.readLine().trim());

        IntStream.range(0, t).forEach(tItr -> {
            try {
                String s = bufferedReader.readLine();

                String result = Result.isBalanced(s);

                bufferedWriter.write(result);
                bufferedWriter.newLine();
            } catch (IOException ex) {
                throw new RuntimeException(ex);
            }
        });

        bufferedReader.close();
        bufferedWriter.close();
    }
}

Merge two sorted linked lists

Merge two sorted linked lists

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 {

    static class SinglyLinkedListNode {
        public int data;
        public SinglyLinkedListNode next;

        public SinglyLinkedListNode(int nodeData) {
            this.data = nodeData;
            this.next = null;
        }
    }

    static class SinglyLinkedList {
        public SinglyLinkedListNode head;
        public SinglyLinkedListNode tail;

        public SinglyLinkedList() {
            this.head = null;
            this.tail = null;
        }

        public void insertNode(int nodeData) {
            SinglyLinkedListNode node = new SinglyLinkedListNode(nodeData);

            if (this.head == null) {
                this.head = node;
            } else {
                this.tail.next = node;
            }

            this.tail = node;
        }
    }

    public static void printSinglyLinkedList(SinglyLinkedListNode node, String sep, BufferedWriter bufferedWriter) throws IOException {
        while (node != null) {
            bufferedWriter.write(String.valueOf(node.data));

            node = node.next;

            if (node != null) {
                bufferedWriter.write(sep);
            }
        }
    }

    // Complete the mergeLists function below.

    /*
     * For your reference:
     *
     * SinglyLinkedListNode {
     *     int data;
     *     SinglyLinkedListNode next;
     * }
     *
     */
    static SinglyLinkedListNode mergeLists(SinglyLinkedListNode head1, SinglyLinkedListNode head2) {
        SinglyLinkedListNode out;
        if(head1.data <= head2.data){
        out = new SinglyLinkedListNode(head1.data);
        head1 = head1.next;
        }else{
            out = new SinglyLinkedListNode(head2.data);
            head2 = head2.next;
        }
        SinglyLinkedListNode last = out;
        while(head1 != null || head2 != null){
            
            if(head1 == null){
                last.next = head2;
                last = last.next;
                head2 = head2.next;
            }else if( head2 == null){
                last.next = head1;
                last = last.next;
                head1 = head1.next;
            }
            else if(head1.data <= head2.data){
                last.next = head1;
                last = last.next;
                head1 = head1.next;
            }else if(head1.data > head2.data){
                last.next = head2;
                last = last.next;
                head2 = head2.next;
            }
        }

return out;
    }

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