Nth Node from End
EasyP1Coding
Given the head of a singly linked list and an integer n, return the value of the n-th node counted from the end of the list (n = 1 is the last node). If the list has fewer than n nodes, return -1.
A list node has val and next. The ListNode class is already defined for you. Aim for a single pass over the list.
Example 1
- Input
- head = [1,2,3,4,5], n = 2
- Output
- 4
Example 2
- Input
- head = [1,2,3,4,5], n = 5
- Output
- 1
Example 3
- Input
- head = [7], n = 2
- Output
- -1
Constraints
- 0 <= number of nodes <= 10^5
- -10^5 <= Node.val <= 10^5
- 1 <= n <= 10^5
Hints
Give it a real attempt first. Run shows which examples fail.
Saved automatically
Run checks the 3 visible tests, Submit all 9. ⌘Enter runs, ⌘⇧Enter submits.