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 ) {
   struct ListNode *current = head;
   struct ListNode *prev = NULL;
   struct ListNode *next = NULL;

   while (current != NULL) {
    next = current->next;  //保留后面的链表
    current->next = prev;  //把当前链表指针域的值变成最后一个值，指针域置为空
    prev = current;        //把第一个值转变成最后一个值赋给prev,
    current = next;        //当前指针向后移动
   }
   return prev;
}