LeetCode--206 反轉連結清單

題目

反轉一個單連結清單。
           

示例

示例:

輸入: 1->2->3->4->5->NULL
輸出: 5->4->3->2->1->NULL
           

class Solution {
public:
    ListNode* reverseList(ListNode* head) {
        if (head == nullptr || head->next == nullptr)
		{
			return head;
		}
		ListNode* pre = head;
		ListNode* cur = head->next;
		ListNode* r;
		head->next = nullptr;
		while (cur != nullptr)
		{
			r = cur->next;
			cur->next = pre;
			pre = cur;
			cur = r;
		}
		head = pre;
		return head;
    }
};