链表的查找

对于数据结构，一直都没有怎么用，但是在面试时一直都会出现。

面试题- 链表

(1)写一个函数将一个链表逆序.

(2)一个单链表，不知道长度，写一个函数快速找到中间节点的位置.

(3)写一个函数找出一个单向链表的倒数第n个节点的指针.(把能想到的最好算法写出).

#include "stdafx.h"
#include <iostream>
#include <math.h>
using namespace std;
struct MyStruct
{
	int data;
	MyStruct *pNext;
};

MyStruct* CreateList(int* p, int len);
MyStruct* PositiveList(MyStruct* pHead);
MyStruct* FindMidNode(MyStruct* pHead);

MyStruct* FindEndIndex(MyStruct* pHead,int nNode);

int main()
{
	int a[8] = {1,2,3,4,5,6,7,8};
	MyStruct *pHead = NULL;
	//创建链表时就让它逆序
	pHead = CreateList(a, 8);


	//逆序输出 5-1

	MyStruct *pPriData= pHead;
	while(pPriData != NULL)
	{
		cout<<"value: "<<pPriData->data<<endl;
		pPriData = pPriData->pNext;
	}
	//正序输出1-5

	cout<<endl;
	cout<<"正序输出"<<endl;
	MyStruct *pData = PositiveList(pHead);
	pPriData = pData;
	while (pPriData != NULL)
	{
		cout<<"value: "<<pPriData->data<<endl;
		pPriData = pPriData->pNext;
	}


	//查找中间的节点
	pPriData = FindMidNode(pHead);
	cout<<"位置为： "<<&pPriData<<"数据为："<<pPriData->data<<endl;


	//查找倒数的节点的数据
	int nNode;
	cout<<"输入要查看的节点"<<endl;
	cin >>nNode;
	pPriData = FindEndIndex(pHead,nNode);
	

	system("pause");
	return 1;
}


MyStruct* FindEndIndex(MyStruct* pHead,int nNode)
{
	//先让pEnd - pBegin = nNode(他们之家的差距)
	MyStruct* pBegin = pHead;
	MyStruct* pEnd = pHead;

	//如果是1就是最后一个节点
	if(nNode == 1)
	{
			while(pBegin->pNext != NULL)
			{
				pBegin = pBegin->pNext;
			}

			return pBegin;
	}
	else
	{
		for(int i =0; i< nNode-1; i++)
		{
			pEnd= pEnd->pNext;
		}
		while(pEnd->pNext != NULL)
		{
			pEnd = pEnd->pNext;
			pBegin = pBegin->pNext;
		}
		return pBegin;
	}

}
MyStruct* FindMidNode(MyStruct* pHead)
{
	MyStruct* pSercher = pHead;
	MyStruct* pMid     = pHead;

	while(pSercher->pNext != NULL)
	{
		pSercher = pSercher->pNext->pNext;
		
		if(pSercher == NULL)
		{
			break;
		}
		pMid = pMid->pNext;
	}

	return pMid;
}


MyStruct* PositiveList(MyStruct* pHead)
{
	MyStruct *pReturn = NULL;
	MyStruct *pData = NULL;

	while(pHead != NULL)
	{
		MyStruct *pTemp = new MyStruct;
		pTemp->data = pHead->data;
		pTemp->pNext = NULL;

		if(pReturn == NULL)
		{
			pReturn = pTemp;
		}
		else
		{
			pTemp->pNext = pReturn;
			pReturn = pTemp;
		}
		pHead = pHead->pNext;
	}

	return pReturn;
}


MyStruct* CreateList(int* p,int len)
{
	MyStruct *pHead = NULL;
	MyStruct *pTemp = NULL;

	for(int i =0; i < len; i++)
	{
		pTemp = new MyStruct;
		pTemp->data = i;
		pTemp->pNext = NULL;
		if(pHead == NULL)
		{
			pHead = pTemp;
		}
		else
		{ 
			pTemp->pNext = pHead;
			pHead= pTemp;
		}
	}


	return pHead;
}

我在自己的电脑上验证通过了，如果感觉思路不好，请给我留言。您的留言是我前进的动力！