In circular linked list, insertion of node requires modification of?

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in circular linked list, insertion of node requires modification of?

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LectureNotes said in circular linked list, insertion of node requires modification of?

Answer:

In a circular linked list, the insertion of a node requires modification of several pointers to maintain the circular nature of the list. Specifically, the pointers that need to be modified depend on where the new node is being inserted: at the beginning, at the end, or at a specific position within the list. Here are the details for each case:

1. Insertion at the Beginning:

  • Modification of the new node’s pointer: The new node’s next pointer should point to the current head of the list.
  • Modification of the last node’s pointer: The last node’s next pointer (which currently points to the old head) should be updated to point to the new node.
  • Modification of the head pointer: The head pointer of the list should be updated to point to the new node.

2. Insertion at the End:

  • Modification of the new node’s pointer: The new node’s next pointer should point to the head of the list.
  • Modification of the last node’s pointer: The current last node’s next pointer should be updated to point to the new node.
  • Modification of the head pointer: No change is needed for the head pointer in this case.

3. Insertion at a Specific Position:

  • Modification of the new node’s pointer: The new node’s next pointer should point to the node that is currently at the desired position.
  • Modification of the previous node’s pointer: The node that is currently before the desired position should have its next pointer updated to point to the new node.

Example:

Let’s consider a circular linked list with nodes A -> B -> C -> A and we want to insert a new node D at the beginning.

  1. Modification of new node’s pointer:

    • D.next = A

  2. Modification of the last node’s pointer:

    • C.next = D

  3. Modification of the head pointer:

    • Head = D

The resulting list will be: D -> A -> B -> C -> D.

In summary, the insertion of a node in a circular linked list requires modification of the new node’s next pointer and the next pointer of the node that will precede the new node. If inserting at the beginning, the head pointer also needs to be updated.