Removing Duplicates from a Sorted Linked List

Problem

Given a sorted singly linked list, remove duplicate nodes so that each element appears only once.

Do not use extra space.
The linked list is already sorted, so duplicates will be adjacent.
Example 1
Input: 2 -> 2 -> 4 -> 5
Output: 2 -> 4 -> 5

Explanation: The value 2 appears twice, so one duplicate is removed.

Example 2
Input: 2 -> 2 -> 2 -> 2 -> 2
Output: 2

Explanation: All nodes have value 2, so only one node remains.

Approach

Start from the head node.
Traverse the linked list.
If the current node value is equal to the next node value, skip the next node.
Otherwise move to the next node.
Continue until the end of the list.

Python Code

def removeDuplicates(head):
curr = head

while curr and curr.next:
    if curr.data == curr.next.data:
        curr.next = curr.next.next  # remove duplicate
    else:
        curr = curr.next           # move forward

return head

Output
2 -> 4 -> 5