Given a linked list, rotate the list to the right by k places, where k is non-negative.
Example 1:
Input: 1->2->3->4->5->NULL, k = 2 Output: 4->5->1->2->3->NULL Explanation: rotate 1 steps to the right: 5->1->2->3->4->NULL rotate 2 steps to the right: 4->5->1->2->3->NULL
Example 2:
Input: 0->1->2->NULL, k = 4 Output:2->0->1->NULLExplanation: rotate 1 steps to the right: 2->0->1->NULL rotate 2 steps to the right: 1->2->0->NULL rotate 3 steps to the right:0->1->2->NULLrotate 4 steps to the right:2->0->1->NULL
Related Topics:
Linked List, Two Pointers
Similar Questions:
// OJ: https://leetcode.com/problems/rotate-list/
// Author: github.com/lzl124631x
// Time: O(N)
// Space: O(1)
class Solution {
int getLength(ListNode *head) {
int len = 0;
for (; head; head = head->next, ++len);
return len;
}
public:
ListNode* rotateRight(ListNode* head, int k) {
if (!head) return NULL;
int len = getLength(head);
k %= len;
if (k == 0) return head;
auto p = head, q = head;
while (k--) q = q->next;
while (q->next) {
p = p->next;
q = q->next;
}
auto h = p->next;
q->next = head;
p->next = NULL;
return h;
}
};// OJ: https://leetcode.com/problems/rotate-list/
// Author: github.com/lzl124631x
// Time: O(N)
// Space: O(1)
class Solution {
public:
ListNode* rotateRight(ListNode* head, int k) {
if (!head) return NULL;
int len = 1;
auto p = head;
for (; p->next; ++len, p = p->next);
p->next = head;
k = len - k % len;
while (k--) p = p->next;
head = p->next;
p->next = NULL;
return head;
}
};