| Problem Description: | Write a program to delete last node from the given Linked List. In order to delete last node, we need to set the second last node's next pointer to NULL value. Our approach is:
- We should consider 3 cases here.
- When head node is null, return null.
- When the linked list contains only head node, then return null.
- In any other case, traverse the linked list and check node.next.next must not null in loop exit condition.
- Once after out of loop, set the node next reference to null and return the head node reference.
|
| LlRemoveLastNode | | package com.java2novice.ds.linkedlist;
public class LlRemoveLastNode {
static class Node {
int data;
Node next;
Node[int tmp] {data = tmp;}
}
static Node removeLastNode[Node head] {
if[head == null || head.next == null] {
return null;
}
// Find the second last node
Node temp = head;
while[temp.next.next != null] {
temp = temp.next;
}
// change the second last node next pointer to null
temp.next = null;
return head;
}
static void printLinkedList[Node head] {
while[head != null] {
System.out.print[head.data+" "];
head = head.next;
}
}
public static void main[String[] a] {
Node n1 = new Node[23];
Node n2 = new Node[29];
Node n3 = new Node[29];
Node n4 = new Node[45];
Node n5 = new Node[45];
Node n6 = new Node[45];
Node n7 = new Node[54];
n1.next = n2;
n2.next = n3;
n3.next = n4;
n4.next = n5;
n5.next = n6;
n6.next = n7;
System.out.print["Initial linked list : "];
printLinkedList[n1];
n1 = removeLastNode[n1];
System.out.println[];
System.out.print["Linked list after removing last node: "];
printLinkedList[n1];
}
}
|
|
| Output: | | Initial linked list : 23 29 29 45 45 45 54
Linked list after removing last node: 23 29 29 45 45 45 |
|
List Of All Interview Programs: |
Difference between Enumeration and Iterator
The functionality of Enumeration and the Iterator are same. You can get remove[] from Iterator to remove an element, while while Enumeration does not have remove[] method. Using Enumeration you can only traverse and fetch the objects, where as using Iterator we can also add and remove the objects. So Iterator can be useful if you want to manipulate the list and Enumeration is for read-only access.
You can never get enough of what you dont really need.
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