程式語言 - LeetCode - C++ - 206. Reverse Linked List

參考資訊：
https://www.cnblogs.com/cnoodle/p/11670754.html

題目：


解答：

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution {
public:
    ListNode* reverseList(ListNode* head) {
        if (!head || !head->next) {
            return head;
        }

        ListNode *pre = NULL;
        ListNode *next = NULL;

        while (head) {
            next = head->next;
            head->next = pre;

            pre = head;
            head = next;
        }

        return pre;
    }
};