面试题4：从尾到头打印链表

方法一：利用栈实现

C++代码：

#include "stdafx.h"#include <iostream>#include <stack>using namespace std;//链表中的结点类型struct ListNode{int m_nKey;ListNode *m_pNext;};//从尾到头打印链表void PrintLinkedListReversely(ListNode *pHead){stack<ListNode *> tempStack;    if (pHead != NULL){ListNode *pCurrent = pHead;        ListNode *pStackNode = NULL;while (pCurrent != NULL){tempStack.push(pCurrent);pCurrent = pCurrent->m_pNext;}        while (!tempStack.empty())        {pStackNode = tempStack.top();cout << pStackNode->m_nKey << " ";tempStack.pop();        }cout << endl;}}

方法二：递归实现

C++代码：

#include "stdafx.h"#include <iostream>#include <stack>using namespace std;//链表中的结点类型struct ListNode{int m_nKey;ListNode *m_pNext;};//从尾到头打印链表void PrintLinkedListReversely(ListNode *pHead){if (pHead != NULL){if (pHead->m_pNext != NULL){PrintLinkedListReversely(pHead->m_pNext);}cout << pHead->m_nKey << " ";}}int _tmain(int argc, _TCHAR* argv[]){bool isHeadNode = true;ListNode *pHeadNode = NULL;ListNode *pListNode = NULL;ListNode *pCurrentTail = NULL;while (1){if (isHeadNode){   pHeadNode = new ListNode();cin >> pHeadNode->m_nKey;pHeadNode->m_pNext = NULL;pCurrentTail = pHeadNode;isHeadNode = false;}else{pListNode = new ListNode();cin >> pListNode->m_nKey;if (pListNode->m_nKey == -1){break;}pListNode->m_pNext = NULL;pCurrentTail->m_pNext = pListNode;pCurrentTail = pListNode;}}PrintLinkedListReversely(pHeadNode);ListNode *pNode = pHeadNode;ListNode *pNext = NULL;while (pNode != NULL){pNext = pNode->m_pNext;delete pNode;pNode = pNext;}   system("pause");return 0;}

基于递归的代码很简洁，但它存在缺点：当链表非常长的时候就会导致函数调用的层级很深，从而有可能导致栈溢出。显然相比方法一用栈基于循环实现的代码的鲁棒性更好些。