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