题解 | #反转链表#

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 *	ListNode(int x) : val(x), next(nullptr) {}
 * };
 */
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param head ListNode类 
     * @return ListNode类
     */
    ListNode* ReverseList(ListNode* head) {
        // write code here
        if(head == nullptr) return head;
        auto* newhead = new ListNode(0);
        while(head->next != nullptr){
            auto tmp = head;
            head = head->next;
            tmp->next = newhead->next;
            newhead->next = tmp;
            
        }
        newhead->val = head->val;
        delete head;
        head= nullptr;
        return newhead;

    }
};