[数据结构与算法]剑指 Offer 24. 反转链表 LCOF

用迭代的方法，

class Solution {
public:
    ListNode* reverseList(ListNode* head) {
        ListNode* prev = nullptr;
        ListNode* curr = head;

        while (curr) {
            ListNode* temp = curr->next;
            curr->next = prev;
            prev = curr;
            curr = temp;
        }

        return prev;
    }
};

看答案还有其他做法，其中就是用递归来做，

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