#include <stdio.h>
#include <stdlib.h>

// Definition for singly-linked list.
struct ListNode {
    int val;
    struct ListNode *next;
};

struct ListNode* rotateRight(struct ListNode* head, int k) {
    if (!head || !head->next || k == 0) {
        return head;
    }
    
    // First pass: get length and make the list circular
    int length = 1;
    struct ListNode* tail = head;
    while (tail->next) {
        tail = tail->next;
        length++;
    }
    
    // Make it circular
    tail->next = head;
    
    // Calculate effective rotation
    k = k % length;
    if (k == 0) {
        tail->next = NULL;  // Break the circle
        return head;
    }
    
    // Find the new tail (length - k - 1 steps from old head)
    int stepsToNewTail = length - k;
    struct ListNode* newTail = head;
    for (int i = 0; i < stepsToNewTail - 1; i++) {
        newTail = newTail->next;
    }
    
    // New head is next of new tail
    struct ListNode* newHead = newTail->next;
    
    // Break the circle
    newTail->next = NULL;
    
    return newHead;
}