《剑指offer3- 从末尾到头打印链表》

题目描述

输入一个链表，按链表值从尾到头的顺序返回一个ArrayList。

 

本质上是逆转链表

 

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/** *  struct ListNode { *        int val; *        struct ListNode *next; *        ListNode(int x) : *              val(x), next(NULL) { *        } *  }; */ class Solution { public:     vector<int> printListFromTailToHead(ListNode* head) {         vector<int> list;         head = this->reverseList(head);         while(head){             list.push_back(head->val);             head = head->next;         }         return list;     }                   ListNode* reverseList(ListNode* head){         if(!head || !head->next){             return head;         }         ListNode* last = NULL;         while(head){             ListNode* next = this->reverseNode(last, head);             last = head;             head = next;         }         return last;     }           ListNode* reverseNode(ListNode* last, ListNode* cur){         ListNode* next = cur->next;         cur->next = last;         return next;     }           //递归的方式会导致堆栈溢出     void dumpListReverse(ListNode* head, vector<int> &list){                   if(!head && !head->next)         {             this->dumpListReverse(head->next, list);         }         list.push_back(head->val);     } };