Problem statement

https://leetcode.com/problems/remove-duplicates-from-sorted-list/

Solution

Go from left to right and check if the current value is equal to the next value.

Complexity

It is O(n) for time and O(1) for space, because we modified original list.

Code

class Solution:
    def deleteDuplicates(self, head):
        curr = head
        while curr and curr.next:
            if curr.next.val == curr.val:
                curr.next = curr.next.next
            else:
                curr = curr.next
        return head