dsa · easy
Remove Duplicates from a Sorted List
You are given head, the node values of a singly linked list in order from the front. The values are already sorted non-decreasing. Collapse every run of equal neighbours so each distinct value appears once, keeping the original relative order. Return the remaining values.
Arguments
head— node values of the sorted list, front to back;[]if empty
An empty list stays empty.
Example
head = [2,2,2,5,5,9]
The three 2s shrink to one 2, the two 5s shrink to one 5, and 9 is already unique, so the result is [2,5,9].
[4] has nothing to collapse → [4].
Constraints
0 <= head.length <= 300 -100 <= head[i] <= 100 head is sorted in non-decreasing order Hidden tests include near-max size for this bound; a slower-than-intended solution TLEs.
Examples
Example 1
Input: [2,2,2,5,5,9] Expected: [2,5,9]
Example 2
Input: [4] Expected: [4]
Example 3
Input: [] Expected: []