Self-practice-01: Check if arrays are matching or not in Java

 import java.util.*;

public class Main

{

    

    

    public static void ifMatch(int[] arr) {

        

        // Combine array with a predefined array

        int[] pattern = {4, 3, 2, 6};

        

        // Check if arrays have same length

        if(Arrays.equals(arr, pattern)) {

            System.out.println("Yes, Array is matching.");

        } else {

            System.out.println("No, Array isn't matching.");

        }

    }

    

    

    

public static void main(String[] args) {

int[] testArr = {4, 3, 2, 6};

System.out.print("Array 1: ");

ifMatch(testArr);

int[] testArr2 = {4, 3, 2, 9};

System.out.print("Array 2: ");

ifMatch(testArr2);

}

}

Circular Queue using Arrays

 public class QueueB {

    static class Queue {

        static int arr[];

        static int size;

        static int rear;

        static int front;

        Queue(int n) {

            arr = new int[n];

            size = n;

            rear = -1;

            front = -1;

        }

        public boolean isEmpty() {

            return rear == -1 && front == -1;

        }

        public boolean isFull() {

            return (rear + 1) % size == front;

        }

        // add

        public void add(int data) {

            if (isFull()) {

                System.out.println("Queue is full");

                return;

            }

            // add 1st element

            if (front == -1) {

                front = 0;

            }

            rear = (rear + 1) % size;

            arr[rear] = data;

        }

        // remove

        public int remove() {

            if (isEmpty()) {

                System.out.println("Queue is empty");

                return -1;

            }

            int result = arr[front];

            // last element deleted

            if (rear == front) {

                rear = front = -1;

            } else {

                front = (front + 1) % size;

            }

            return result;

        }

        // peek

        public int peek() {

            if (isEmpty()) {

                System.out.println("Queue is empty");

                return -1;

            }

            return arr[front];

        }

    }

    public static void main(String args[]) {

        Queue q = new Queue(3);

        q.add(1);

        q.add(2);

        q.add(3);

        // adding condition that works like a circular queue

        System.out.println(q.remove()); // prints 1

        q.add(4);

        System.out.println(q.remove()); // prints 2

        q.add(5);

        // queue now contains 3,4,5 in order

        while (!q.isEmpty()) {

            System.out.println(q.peek());

            q.remove();

        }

    }

} OUTPUT: 1 2

3

4

5

Delete N Nodes After M Nodes in a Linked List (Leetcode Premium Problem)

 

Delete N Nodes After M Nodes in a Linked List

Difficulty Level: Rookie

In this problem, you are given a linked list and two integers, M and N. You need to traverse the linked list such that you:

1. Retain M nodes, then

2. Delete the next N nodes, and

3. Repeat this process until the end of the linked list.

---

Problem Statement

• Input: A linked list and two integers M and N

• Output: The modified linked list after deleting N nodes after every M nodes

Intersection of Two Linked List (Leetcode-160)

 /**

 * Definition for singly-linked list.

 * public class ListNode {

 *     int val;

 *     ListNode next;

 *     ListNode(int x) {

 *         val = x;

 *         next = null;

 *     }

 * }

 */

public class Solution {

    public ListNode getIntersectionNode(ListNode headA, ListNode headB) {

        // if either list are null, return null since no intersection

        if(headA == null || headB == null) {

            return null;

        }

        // set up two runners

        ListNode pA = headA;

        ListNode pB = headB;

        while(pA != pB) {

            pA = (pA == null) ? headB : pA.next;

            pB = (pB == null) ? headA : pB.next;

        }

        return pA;

    }

} OUTPUT: All cases are true.