Rearrange Last N

# Rearrange Last N

February 28, 2023 Name
Moch Lutfi
@kaptenupi

## Problem

Note: Try to solve this task in `O(list size)` time using `O(1)` additional space, since this is what you'll be asked during an interview.

Given a singly linked list of integers `l` and a non-negative integer `n`, move the last `n` list nodes to the beginning of the linked list.

Example

• For `l = [1, 2, 3, 4, 5]` and `n = 3`, the output should be
`solution(l, n) = [3, 4, 5, 1, 2]`;
• For `l = [1, 2, 3, 4, 5, 6, 7]` and `n = 1`, the output should be
`solution(l, n) = [7, 1, 2, 3, 4, 5, 6]`.

## Solution

`// Singly-linked lists are already defined with this interface:// type ListNode struct {// Value interface{}// Next *ListNode// }//func solution(l *ListNode, n int) *ListNode { if l == nil || l.Next == nil || n == 0 { return l } // Count the length of the list length := 1 lastNode := l for lastNode.Next != nil { length++ lastNode = lastNode.Next } // Handle edge cases n = n % length if n == 0 { return l } // Find the new head and tail of the list newTail := l for i := 1; i < length-n; i++ { newTail = newTail.Next } newHead := newTail.Next // Update pointers lastNode.Next = l newTail.Next = nil return newHead}`