CA 23 - Remove Duplicates in Sorted Linked List

Problem Remove Duplicates in Sorted Linked List You are given a sorted singly linked list. Your task is to remove duplicate nodes, keeping only one occurrence of each element. The solution should be done in-place with O(1) extra space. Examples Input: 2 → 2 → 4 → 5 Output: 2 → 4 → 5 Input: 2 → 2 → 2 → 2 → 2 Output: 2 Approach Since the list is already sorted, duplicate values will always be adjacent. Steps: Traverse the list using a pointer curr Compare the current node with the next node: If they are equal → skip the next node (curr.next = curr.next.next) Otherwise → move to the next node Continue until the end of the list This removes duplicates without using extra space. Complexity: Time Complexity: O(n) Space Complexity: O(1) class ListNode: def __init__(self, val=0, next=None): self.val = val self.next = nex def removeDuplicates(head): curr = head while curr and curr.next: if curr.val == curr.next.val: curr.next = curr.next.next else: curr = curr.next return head head = ListNode(2