Remove Duplicates from Sorted Linked List

Problem Statement

Given the head of a sorted linked list, delete all duplicates such that each element appears only once. Return the linked list sorted as well.

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Example

Input
1 -> 1 -> 2 -> 3 -> 3

Output
1 -> 2 -> 3

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Approach Iterative Method

Since the list is already sorted, duplicates will be adjacent. We can compare current node with the next node and remove duplicates.

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Steps

1 Start from the head node
2 Compare current node with next node
3 If both values are equal, skip the next node
4 Else move to the next node
5 Repeat until end of list

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Code

```python id="rdll1"
class ListNode:
def init(self, val=0, next=None):
self.val = val
self.next = next

def deleteDuplicates(head):
current = head

while current and current.next:
    if current.val == current.next.val:
        current.next = current.next.next
    else:
        current = current.next

return head

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## Explanation

Since the list is sorted, all duplicate values are next to each other. We simply skip the duplicate nodes by changing the pointer of the current node.

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## Expected Output

Input
1 -> 1 -> 2 -> 3 -> 3

Output
1 -> 2 -> 3

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## Conclusion

This problem helps in understanding linked list traversal and pointer manipulation. It is simple yet important for mastering linked list operations.

Practice this problem to improve your confidence in working with linked lists.