C ++程序实现排序的双链表
在数据结构中，链接列表是数据元素的线性集合。列表中的每个元素或节点都包含两项-数据和对下一个节点的引用。最后一个节点具有对null的引用。进入链接列表的入口点称为列表的开头。
双链列表由一组称为节点的顺序链接的记录组成。每个节点包含三个字段：一个数据字段和两个链接字段；引用节点序列字段中的上一个和下一个节点。
如果是排序的双链表，则根据排序的数据字段值，链表将保持排序状态。
算法
Begin
function createnode() to insert node in the list:
it creates a newnode and inserts the number in the data field of the newnode.
It checks whether the list is empty or not. If the list is empty put the node as first element and update head.
Both prev and next pointers will be initialized with NULL.
If list is not empty, then this newnode will be inserted into the existing linked list in such a way that ultimately the linked list will remain sorted.
Prev and next pointers will be updated accordingly.
End
Begin
function display_head() to display the list from the head:
Initialize c=0.
Initialize pointer variable with the head node address
while (c <= i )
Print the node info
Update pointer variable
Increment c.
End
Begin
function dispslay_tail() to display the list from the tail:
Initialize m=0.
Initialize pointer variable with the tail node address
while (m <= i )
Print the node info
Update pointer variable
Increment m.
End范例程式码
#include<iostream>
using namespace std;
struct nod {
int d;
nod *n, *p;
}
*p = NULL, *head = NULL, *r = NULL, *np = NULL, *tail = NULL;
int c = 0;
void createnode(int n) {
np = new nod;
np->d = n;
np->n = NULL;
np->p = NULL;
if (c == 0) {
tail = np;
head = np;
p = head;
p->n = head;
p->p = head;
c++;
} else if (c == 1) {
p = head;
r = p;
if (np->d < p->d) {
np->n = p;
p->p = np;
head = np;
p->n = np;
np->p = p;
tail = p;
} else if (np->d > p->d) {
p->n = np;
np->p = p;
np->n= head;
p->p = np;
}
c++;
} else {
p = head;
r = p;
if (np->d < p->d) {
np->n = p;
p->p = np;
head = np;
do {
p = p->n;
}
while (p->n != r);
tail = p;
p->n = np;
np->p = p;
} else if (np->d > p->d) {
while (p->n != head && np->d > p->d) {
r = p;
p = p->n;
if (p->n == head && (p->d < np->d)) {
p->n = np;
np->p = p;
np->n = head;
tail = np;
head->p = np;
break;
} else if (np->d< p->d) {
r->n= np;
np->p = r;
np->n= p;
p->p= np;
if (p->n != head) {
do {
p = p->n;
}
while (p->n != head);
}
tail = p;
break;
}
}
}
}
}
void display_head(int i) {
nod *t = head;
int c = 0;
while (c <= i) {
cout<<t->d<<"\t";
t = t->n;
c++;
}
cout<<endl;
}
void display_tail(int i) {
nod *t = tail;
int m = 0;
while (m <= i) {
cout<<t->d<<"\t";
t = t->p;
m++;
}
cout<<endl;
}
int main() {
int i = 0, n, a, ch;
cout<<"enter the no of nodes\n";
cin>>n;
while (i < n) {
cout<<"\nenter value of node\n";
cin>>a;
createnode(a);
i++;
}
cout<<"\nsorting Doubly Linked List head first\n";
display_head(n);
cout<<"\nsorting Doubly Linked List tail first\n";
display_tail(n);
}输出结果
enter the no of nodes 5 enter value of node 7 enter value of node 4 enter value of node 6 enter value of node 2 enter value of node 1 sorting Doubly Linked List head first 1 2 4 6 7 1 sorting Doubly Linked List tail first 7 6 4 2 1 7