今天真是嚇死寶寶了

作為一個弱鳥菜鳥蜻蜓點水鳥，竟然今天AC出來個100%勝出，有點暈頭轉(zhuǎn)向=。=

嚇死了.png

206. Reverse Linked List

Reverse a singly linked list.
A linked list can be reversed either iteratively or recursively. Could you implement both?
也是得益于Discuss的啟發(fā)?，F(xiàn)在把我理解后自己寫的代碼展出：

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* reverseList(ListNode* head) {
        ListNode *todo = NULL, *now = head, *pre = NULL;
        while(now){
            todo = now -> next;
            now -> next = pre;
            pre = now;
            now = todo;
        }
        return pre;
    }
};

554811933326058546.jpg

寫代碼還是需要紙和筆

鏈表這東西，我在腦袋上都沒搞清楚怎么翻轉(zhuǎn)，那代碼更不可能了。后來發(fā)現(xiàn)紙筆驗算下還是可以的，說白了還是我的腦袋的內(nèi)存不夠，不夠驗算的~