Remove Duplicates From a Sorted List

L6 Medium Linked List

Concept

Sorted lists keep duplicates adjacent, so a single pass that skips equal neighbors is enough to leave only distinct values.

Given the head of a sorted linked list, delete all nodes that appear more than once, keeping only one copy of each value. Return the head.

Examples

▸ head = [1, 1, 2]

→ [1, 2]

▸ head = [1, 1, 2, 3, 3]

→ [1, 2, 3]

▸ head = [1, 1, 1]

→ [1]

Progressive Hints

Hint 1 · Nudge

In a sorted list, duplicates always sit right next to each other, so only local comparisons matter.

Hint 2 · Plan

Walk the list with the current node. While the next node carries the same value, skip it. Then step to the next distinct value.

Hint 3 · Approach

cur = head. While cur and cur.next exist: if cur.val == cur.next.val then cur.next = cur.next.next else cur = cur.next. Return head.

Output

// Run your code to see the output here.