题解 | #反转链表#

/**
 * struct ListNode {
 *  int val;
 *  struct ListNode *next;
 * };
 */
/**
 * 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
 */
struct ListNode* ReverseList(struct ListNode* head ) {
    if (head == NULL || head->next == NULL)
        return head;

    struct ListNode *newhead = NULL;
    while(head)
    {
        struct ListNode *next = head->next;
        head->next = newhead;
        newhead = head;
        head = next;
    }
    return newhead;
}