LeetCode 237: Delete Node in a Linked List

Meta Data

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Difficulty: medium First Attempt: 2022-08-22

• Submissions: Accepted (first try)

Approach

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Only the node to delete is given, not its predecessor, so nothing can skip over it. Instead copy the next node’s value into this one and delete the next node (Linked List, Others). The node is guaranteed not to be the tail, so the next node exists.

My Solution

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class Solution:
    def deleteNode(self, node):
        node.val = node.next.val
        node.next = node.next.next

Complexity

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Time O(1), space O(1).

Mistakes to Avoid

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• This trick only works when the node is not the tail.

Interview Explanation

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Without the predecessor the node cannot truly remove itself, so I copy the next node’s value and skip the next node, which has the same effect. Time O(1).