Java Exercises: Swap every two adjacent nodes of a given linked list

Java Basic: Exercise-180 with Solution

Write a Java program to swap every two adjacent nodes of a given linked list.

Pictorial Presentation:

Sample Solution:

Java Code:

import java.util.*;
public class Solution {
 public static void main(String[] args) {
  ListNode l = new ListNode(10);
  l.next = new ListNode(20);
  l.next.next = new ListNode(30);
  l.next.next.next = new ListNode(40);
  l.next.next.next.next = new ListNode(50);
  System.out.println("\nOriginal Linked list:");
  printList(l);
  ListNode p = swap_Pairs(l);
  System.out.println("\n\nAfter swiping Linked list becomes:");
  printList(p);
 }
 public static ListNode swap_Pairs(ListNode head) {
  ListNode temp = new ListNode(0);
  temp.next = head;
  head = temp;
  while (head.next != null && head.next.next != null) {
   ListNode a = head.next;
   ListNode b = head.next.next;
   head.next = b;
   a.next = b.next;
   b.next = a;
   head = a;
  }
  return temp.next;
 }
 static void printList(ListNode p) {

  while (p != null) {
   System.out.print(p.val);
   if (p.next != null) {
    System.out.print("->");
   }
   p = p.next;
  }
 }
}
class ListNode {
 int val;
 ListNode next;

 ListNode(int x) {
  val = x;
 }
}

Sample Output:

Original Linked list:
10->20->30->40->50

After swiping Linked list becomes:
20->10->40->30->50

Flowchart:

Java Code Editor:

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