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Rotate List

Problem​

Given the head of a linked list, rotate the list to the right by k places.

Solution Approach​

Click - to see solution code
class Solution {
   public:
    ListNode* rotateRight(ListNode* head, int k) {
        ListNode* temp = head;
        if (!head) return head;
        int n = 1;
        while (temp->next) {
            n++;
            temp = temp->next;
        }
        if (k % n == 0) return head;
        k = k % n;
        temp->next = head;
        temp = head;
        int cnt = 1;
        while (cnt < n - k) {
            cnt++;
            temp = temp->next;
        }
        ListNode* newhead = temp->next;
        temp->next = NULL;
        return newhead;
    }
};