Rotate List

class Solution {
public:
    ListNode* rotateRight(ListNode* head, int k) {
        if (!head || !head->next || k == 0) return head;
        int n = 1;
        ListNode* tail = head;
        while (tail->next) { tail = tail->next; ++n; }
        k %= n;
        if (k == 0) return head;
        tail->next = head;
        ListNode* newTail = head;
        for (int i = 0; i < n - k - 1; ++i) newTail = newTail->next;
        ListNode* newHead = newTail->next;
        newTail->next = nullptr;
        return newHead;
    }
};

func rotateRight(head *ListNode, k int) *ListNode {
    if head == nil || head.Next == nil || k == 0 {
        return head
    }
    n := 1
    tail := head
    for tail.Next != nil {
        tail = tail.Next
        n++
    }
    k %= n
    if k == 0 {
        return head
    }
    tail.Next = head
    newTail := head
    for i := 0; i < n-k-1; i++ {
        newTail = newTail.Next
    }
    newHead := newTail.Next
    newTail.Next = nil
    return newHead
}

from typing import Optional

class Solution:
    def rotateRight(self, head: Optional[ListNode], k: int) -> Optional[ListNode]:
        if not head or not head.next or k == 0:
            return head
        n = 1
        tail = head
        while tail.next:
            tail = tail.next
            n += 1
        k %= n
        if k == 0:
            return head
        tail.next = head
        new_tail = head
        for _ in range(n - k - 1):
            new_tail = new_tail.next
        new_head = new_tail.next
        new_tail.next = None
        return new_head

function rotateRight(head, k) {
    if (!head || !head.next || k === 0) return head;
    let n = 1;
    let tail = head;
    while (tail.next) {
        tail = tail.next;
        n++;
    }
    k %= n;
    if (k === 0) return head;
    tail.next = head;
    let newTail = head;
    for (let i = 0; i < n - k - 1; i++) {
        newTail = newTail.next;
    }
    const newHead = newTail.next;
    newTail.next = null;
    return newHead;
}

class Solution {
    public ListNode rotateRight(ListNode head, int k) {
        if (head == null || head.next == null || k == 0) return head;
        int n = 1;
        ListNode tail = head;
        while (tail.next != null) {
            tail = tail.next;
            n++;
        }
        k %= n;
        if (k == 0) return head;
        tail.next = head;
        ListNode newTail = head;
        for (int i = 0; i < n - k - 1; i++) newTail = newTail.next;
        ListNode newHead = newTail.next;
        newTail.next = null;
        return newHead;
    }
}

function rotateRight(head: ListNode | null, k: number): ListNode | null {
    if (head === null || head.next === null || k === 0) return head;
    let n = 1;
    let tail: ListNode = head;
    while (tail.next !== null) {
        tail = tail.next;
        n++;
    }
    k %= n;
    if (k === 0) return head;
    tail.next = head;
    let newTail: ListNode = head;
    for (let i = 0; i < n - k - 1; i++) {
        newTail = newTail.next!;
    }
    const newHead: ListNode | null = newTail.next;
    newTail.next = null;
    return newHead;
}