[Leetcode] Rotate List

最新推荐文章于 2019-05-16 11:19:14 发布

原创最新推荐文章于 2019-05-16 11:19:14 发布 · 423 阅读

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本文介绍了一种链表操作算法——链表右旋转。通过实例详细解释了如何将一个链表向右旋转k个位置，并提供了完整的C++实现代码。该算法适用于链表长度为非负数的情况。

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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.

class Solution{
public:
	ListNode *rotateRight(ListNode *head, int k) {

		if(head==NULL) return NULL;
		int length = 0;
		ListNode *current = head;
		while(current)
		{
			current = current->next;
			length ++;
		}
		k %= length;
		if(k==0) return head;

		ListNode *vHead = new ListNode(-1);
		vHead->next = head;
		int count = 0;
		current = head;
		ListNode *newTail = vHead;
		while(count<length-k)
		{
			current = current->next;
			newTail = newTail->next;
			count++;
		}
		vHead->next = current;
		newTail->next = NULL;

		while(current->next)
		{
			current=current->next;
		}
		current->next = head;

		return vHead->next;

	}
};