数据结构系列5 - 双循环链表 - C语言实现

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
#include <stdio.h>
#include <stdlib.h>

typedef struct Node{
int data;
struct Node* pre;
struct Node* next;
}Node;

Node* initList(){
Node* L = (Node*)malloc(sizeof(Node));
L->data = 0;
L->pre = L;
L->next = L;
return L;
}

void headInsert(Node* L, int data){
Node* node = (Node*)malloc(sizeof(Node));
node->data = data;
if(L->data == 0){
// 链表为空
node->pre = L;
node->next = L->next;
L->next = node;
L->pre = node;
L->data ++;
}
else{
// 链表不为空
node->next = L->next;
node->pre = L;
L->next->pre = node;
L->next = node;
L->data ++;
}
}

void tailInsert(Node* L, int data){
Node* node = L;
while(node->next != L){
node = node->next;
}
Node* n = (Node*)malloc(sizeof(Node));
n->data = data;
n->pre = node;
n->next = L;
L->pre = n;
node->next = n;
L->data ++;
}

int delete(Node* L, int data){
Node* node = L->next;
while(node != L){
if(node->data == data){
node->pre->next = node->next;
node->next->pre = node->pre;
free(node);
L->data --;
return 1;
}
node = node->next;
}
return 0;
}

void printList(Node* L){
Node* node = L->next;
while(node != L){
printf("%d -> ", node->data);
node = node->next;
}
printf("NULL\n");
}

int main()
{
Node* L = initList();
headInsert(L, 1);
headInsert(L, 2);
headInsert(L, 4);
headInsert(L, 5);
printList(L);
tailInsert(L, 6);
tailInsert(L, 7);
printList(L);
delete(L, 2);
delete(L, 4);
printList(L);
return 0;
}