[LeetCode] 237. Delete Node in a Linked List

Delete Node in a Linked List

Link to original Problem on LeetCode

Write a function to delete a node (except the tail) in a singly linked list, given only access to that node.

Given linked list – head = [4,5,1,9], which looks like following:

Example 1:

Input: head = [4,5,1,9], node = 5

Output: [4,1,9]

Explanation: You are given the second node with value 5, the linked list should become 4 -> 1 -> 9 after calling your function.

Example 2:

Input: head = [4,5,1,9], node = 1

Output: [4,5,9]

Explanation: You are given the third node with value 1, the linked list should become 4 -> 5 -> 9 after calling your function.

Note:

• The linked list will have at least two elements.
• All of the nodes’ values will be unique.
• The given node will not be the tail and it will always be a valid node of the linked list.
• Do not return anything from your function.

Company: Amazon, Goldman Sachs, Microsoft, Samsung, Visa

Solution:

Time Complexity: O(1) Space Complexity: O(1)

class Solution(object):
    def deleteNode(self, node):
        """
        :type node: ListNode
        :rtype: void Do not return anything, modify node in-place instead.
        """
        # You have been given the reference to the node which is to be deleted
        # The simple way to delete is to:
        # -> change the value of the current node with the value of next node
        # -> again the reference to the next attribute is to be changed with the reference of next to next node
        node.val, node.next = node.next.val, node.next.next