103 Delete Node in a Linked List

Delete Node in a Linked List Delete

Problem Summary

You are given only a reference to a node (not the head) in a singly linked list. The node is not the tail.
You need to delete this node from the list.

What You Cannot Do

• You cannot traverse from the head to find the previous node.

• You do not have access to the previous node, so you can't modify its next pointer.

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What You Can Do (The Trick )

You copy the value of the next node into the current node, and then delete the next node instead.

ref

class Node:
    def deleteNode(node: ListNode) -> None:
        node.val = node.next.val        # Step 1: Copy value from next node
        node.next = node.next.next      # Step 2: Skip the next node