链表排序、链表删除、访问倒数第k个节点
1.设一个带头结点的单向链表的头指针为head，设计算法，将链表的记录，按照data域的值递增排序。
2.已知线性表中的元素以单链表作存储结构。试写一算法，删除表中所有大于x且小于y的元素（若表中存在这样的元素）同时释放被删除结点空间。
3.输出该链表中倒数第k个结点， tail为倒数第0个节点
//
#include "stdafx.h"
#include<iostream>
using namespace std;
template<class T>
struct Node{
T value;
Node*next;
};
template<class T>
class list
{
private:
Node<T>*head;
Node<T>*tail;
int len;//链表长度
public:
list();
Node<T>*append(T ele);
Node<T>*findKthfromhead(int k);
Node<T>*findKthfromtail(int k);
Node<T>*sort_list(int endpos);//链表排序
Node<T>*delete_list(T x, T y);//删除表中所有大于x且小于y的元素（若表中存在这样的元素）
Node<T>*reverse_list();//反转Node<T>*list<T>::delete_exist();//删除重复元素
int length();
};
template<class T>
Node<T>*list<T>::reverse_list()
{
<span style="white-space:pre"> </span>int k1 = length()-1;
<span style="white-space:pre"> </span>int k2 = 0;
<span style="white-space:pre"> </span>while (k1 - k2 > 0)
<span style="white-space:pre"> </span>{
<span style="white-space:pre"> </span>int mm;
<span style="white-space:pre"> </span>mm = findKthfromhead(k1)->value;
<span style="white-space:pre"> </span>findKthfromhead(k1)->value = findKthfromhead(k2)->value;
<span style="white-space:pre"> </span>findKthfromhead(k2)->value = mm;
<span style="white-space:pre"> </span>--k1;
<span style="white-space:pre"> </span>++k2;
<span style="white-space:pre"> </span>}
<span style="white-space:pre"> </span>return head;
}
template<class T>
Node<T>*list<T>::delete_list(T x, T y)
{
_ASSERT(y > x);
_ASSERT(len > 0);
sort_list(len - 1);
if (head->value >= y || tail->value <= x)
return head;
if (head->value > x)
{
Node<T>*m = new Node < T >;
while (head->value < y)
{
Node<T>*node = new Node < T > ;
node = head;
if (head->next == NULL)
{
head = NULL;
len = 0;
return head;
}
head->value = head->next->value;
head = head->next;
--len;
delete node;
}
return head;
}
Node<T>*node = new Node < T >;
Node<T>*m = new Node < T >;
node = head;
while (node->value <= x)
{
m = node;
m->value = node->value;
node = node->next;
}
while (node->value < y)
{
Node<T>*n = new Node < T > ;
n = node;
if (node->next == NULL)
{
m->next = NULL;
tail = m;
--len;
return head;
}
node->value = node->next->value;
node = node->next;
--len;
delete n;
}
m->next = node;
return head;
}
template<class T>
Node<T>*list<T>::sort_list(int endpos)//递归实现排序
{
int k = 0;
int pp;
if (endpos == 0)
return head;
Node<T>*node = new Node < T >;
node = head;
while (k < endpos)
{
if (node->value > node->next->value)
{
pp = node->value;
node->value = node->next->value;
node->next->value = pp;
}
++k;
node = node->next;
}
--endpos;
sort_list(endpos);
//delete node;
}
template<class T>
Node<T>*list<T>::findKthfromhead(int k)
{
//if (len == 0)
// return NULL;
_ASSERT(k < len);
Node<T>*KthNode = new Node < T > ;
KthNode = head;
while (k)
{
KthNode = KthNode->next;
--k;
}
return KthNode;
}
template<class T>
Node<T>*list<T>::findKthfromtail(int k)
{
_ASSERT(k < len);
return findKthfromhead(len-1-k);
}
template<class T>
int list<T>::length()
{
return len;
}
template<class T>
Node<T>*list<T>::append(T ele)
{
if (head == NULL)
{
head = new Node < T > ;
tail = new Node < T >;
head->value = ele;
head->next = NULL;
tail->value = ele;
tail->next = NULL;
len = 1;
return head;
}
if (head->next == NULL)
{
head->next = tail;
tail->value = ele;
tail->next = NULL;
len = 2;
return head;
}
else
{
Node<T>*node = new Node < T > ;
node->next = NULL;
node->value = ele;
tail->next = node;
tail = node;
++len;
return head;
}
}
template<class T>
list<T>::list()
{
head = NULL;
tail = NULL;
len = 0;
}
template<class T>
Node<T>*list<T>::delete_exist()
{
<span style="white-space:pre"> </span>sort_list(len - 1);
<span style="white-space:pre"> </span>
<span style="white-space:pre"> </span>Node<T>* node,*n,*m;
<span style="white-space:pre"> </span>n=node = head;
<span style="white-space:pre"> </span>
<span style="white-space:pre"> </span>while (node->next != NULL)
<span style="white-space:pre"> </span>{
<span style="white-space:pre"> </span>
<span style="white-space:pre"> </span>if (node->value == node->next->value)
<span style="white-space:pre"> </span>{
<span style="white-space:pre"> </span>while (node->next != NULL&&node->value == node->next->value)
<span style="white-space:pre"> </span>{
<span style="white-space:pre"> </span>m = node;
<span style="white-space:pre"> </span>node = node->next;
<span style="white-space:pre"> </span>delete m;
<span style="white-space:pre"> </span>--len;
<span style="white-space:pre"> </span>}
<span style="white-space:pre"> </span>n->next = node;
<span style="white-space:pre"> </span>node = node->next;
<span style="white-space:pre"> </span>
<span style="white-space:pre"> </span>}
<span style="white-space:pre"> </span>else
<span style="white-space:pre"> </span>{
<span style="white-space:pre"> </span>n = node;
<span style="white-space:pre"> </span>node = node->next;
<span style="white-space:pre"> </span>}
<span style="white-space:pre"> </span>}
<span style="white-space:pre"> </span>/*
<span style="white-space:pre"> </span>while (node->next != NULL)
<span style="white-space:pre"> </span>{
<span style="white-space:pre"> </span>m = n->next;
<span style="white-space:pre"> </span>m->value = n->next->value;
<span style="white-space:pre"> </span>while (n->value == n->next->value)
<span style="white-space:pre"> </span>{
<span style="white-space:pre"> </span>m = n;
<span style="white-space:pre"> </span>m->value = n->value;
<span style="white-space:pre"> </span>n->value = n->next->value;
<span style="white-space:pre"> </span>n = n->next;
<span style="white-space:pre"> </span>if (n->next == NULL)
<span style="white-space:pre"> </span>{
<span style="white-space:pre"> </span>//delete m;
<span style="white-space:pre"> </span>--len;
<span style="white-space:pre"> </span>return head;
<span style="white-space:pre"> </span>}
<span style="white-space:pre"> </span>//delete m;
<span style="white-space:pre"> </span>--len;
<span style="white-space:pre"> </span>}
<span style="white-space:pre"> </span>node->next = m;
<span style="white-space:pre"> </span>node->next->value = m->value;
<span style="white-space:pre"> </span>n = n->next;
<span style="white-space:pre"> </span>n->value = n->next->value;
<span style="white-space:pre"> </span>}
<span style="white-space:pre"> </span>*/
<span style="white-space:pre"> </span>return head;
}
int _tmain(int argc, _TCHAR* argv[])
{
list<int>aa;
aa.append(6);
cout <<"长度为"<< aa.length() << endl;
aa.append(5);
cout << "长度为" << aa.length() << endl;
aa.append(4);
cout << "长度为" << aa.length() << endl;
aa.append(3);
cout << "长度为" << aa.length() << endl;
aa.append(2);
cout << "长度为" << aa.length() << endl;
cout <<"第三个数为"<< aa.findKthfromhead(3)->value << endl;
cout << "倒数第三个数为" << aa.findKthfromtail(3)->value << endl;
aa.sort_list(aa.length() - 1);
//aa.delete_list(1, 7);
aa.delete_list(1, 4);
cout << "长度为" << aa.length() << endl;
for (int i = 0; i < aa.length(); i++)
cout << aa.findKthfromhead(i)->value << endl;
system("pause");
return 0;
}
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