单链表逆置的递归与非递归算法 [简单的小算法练习]

[问题表述]

单链表逆置的算法，不管是递归还是非递归的情况下，其实策略有多种，此处只列出其中一种

[问题解答]

]/*
* main.cpp
*
*  Created on: 2009-6-24
*      Author: NeeSky
*/
#include <iostream>
using namespace std;
/**
*Single Link List and Its Node's definition
*/
typedef struct TNode
{
int k;
TNode *next;
} Node , *SingleLink;
/***
*Create Single Link List, and  the min Content integer is StartContent
* @param len:                      Link's Node number
* @param startContent:         len+startContent-1 --> ... --> startContent
* @param end:                     the last node's next pointer
*/
SingleLink CreateSingleLink(const int len, int startContent, Node *end )
{
Node *pNode = NULL;
Node *postNode = end;
for (int i = 0; i < len; ++i)
{
pNode = new Node;
pNode->k = i + startContent;
pNode->next = postNode;
postNode = pNode;
}
return pNode;
}
/***
* Reverse The SingleLink
* @return the Head Pointer
*/
SingleLink ReverseSingleLinkWhile(SingleLink sLink )
{
Node *head = sLink;
Node *p1 = head;
Node *p2 = head;
while (p2->next != NULL) //Assigned the value
{
head = p2->next;p2->next = head->next;head->next = p1;
p1 = head;
}
return head;
}
/***
* Reverse the SingLink with Recusrse method
* @param sLink
* @param p
* @return Head of Singlink
*/
SingleLink ReverseSingleLinkRecurse(SingleLink sLink, Node * p = 0)
{
if(p==0)p=sLink->next;
if (p != NULL)
{
Node *head = p;
if (p->next != NULL)
{
swap(p->k, p->next->k);head = p->next;p->next = head->next;head->next = sLink;
sLink = head;
return ReverseSingleLinkRecurse(sLink, p);      //Recurse Method
}
else
{
Node *tour=sLink; while(tour->next!=p)tour=tour->next;
tour->next=NULL;p->next=sLink;
sLink=p;
return sLink;   //the exit of Recurse
}
}
return sLink;           //the exit of Recurse
}
/***
* Show the SingleLinkList
* @param sLink
*/
void ShowSingleLinkList(SingleLink sLink )
{
Node *p = sLink;
cout << "SingleLink("<<sLink<<") ";
for (; p != NULL; p = p->next)
{
cout << "->("<<p<<")" << p->k;
}
cout << endl;
return;
}
/***
* The Main Programming
* @return
*/
int main()
{
SingleLink sLink = CreateSingleLink(10, 1, NULL );
ShowSingleLinkList(sLink);
sLink = ReverseSingleLinkWhile(sLink);
ShowSingleLinkList(sLink);
sLink=ReverseSingleLinkRecurse(sLink);
ShowSingleLinkList(sLink);
return 0;
}

[程序的输出]:

SingleLink(0x3d2578) ->(0x3d2578
)10->(0x3d2568)9->(0x3d2558)8->(0x3d2548)7->(0x3d2538)6->(0x3d2528)5->(0x3d2518)4->(0x3d2508)3->(0x3d24f8)2->(0x3d2490)1

SingleLink(0x3d2490) ->(0x3d2490)1->(0x3d24f8)2->(0x3d2508)3->(0x3d2518)4->(0x3d2528)5->(0x3d2538)6->(0x3d2548)7->(0x3d2558)8->(0x3d2568)9->(0x3d2578)10

SingleLink(0x3d24f8) ->(0x3d24f8
)10->(0x3d2578
)9->(0x3d2568)8->(0x3d2558)7->(0x3d2548)6->(0x3d2538)5->(0x3d2528)4->(0x3d2518)3->(0x3d2508)2->(0x3d2490)1

注意红色的部分“地址”不同是 由于采取的策略方式的原因。