Rotate List

Rotate List

Given a list, rotate the list to the right by k places, where k is non-negative.

For example:
Given 1->2->3->4->5->NULL and k = 2,
return 4->5->1->2->3->NULL.

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode *rotateRight(ListNode *head, int k) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if (!head || !head->next || !k) return head;
        ListNode* front = head;
        for(int ii = 0; ii < k; ++ii){
            front = front->next;
            if (!front) front = head;
        }
        ListNode* it = head;
        while(front->next){
            front = front->next;
            it = it->next;
            if (!it) it = head;
        }
        front->next = head;
        head = it->next;
        it->next = NULL;
        return head;
    }
};