直接上代码吧： 因为是双链表，所以快排的i指针后移和j指针前移可以实现。故而可按照数组快排的方式实现双链表快排。
关键是注意边界，因为是双链表，切莫越界。
1 # include<stdio.h>
2
3 struct dll{
4 struct Element* head;
5 int size;
6 };
7
8 struct Element{
9 int value;
10 struct Element* p;
11 struct Element* r;
12 };
13
14 typedef struct Element Element;
15 typedef struct dll dll;
16
17 void add(dll* m, int k){
18 Element* ptr;
19 Element* head;
20 head = (int *)malloc(10 * sizeof(int));
21 ptr = (int *)malloc(10 * sizeof(int));
22 ptr->value = k;
23 head = m->head;
24 ptr->r = head;
25 ptr->p = head->p;
26 ptr->p->r = ptr;
27 ptr->r->p = ptr;
28 (m->size) = (m->size) + 1;
29
30 }
31 void init(dll* m, int k){
32
33
34 Element* ptr;
35 Element* head;
36 head = (int *)malloc(10 * sizeof(int));
37 ptr = (int *)malloc(10 * sizeof(int));
38 ptr->value = k;
39 m->head = ptr;
40 ptr->r = ptr;
41 ptr->p = ptr;
42 m->size = m->size + 1;
43 }
44
45 Element* qsort(Element* f, Element* l){
46 Element* i = f;
47 Element* s = f;
48 Element* j = l;
49 int tmp = i->value;
50 while (i != j){
51 while ((i != j) && (j->value) >= tmp)
52 {
53 j = j->p;
54 }
55 i->value = j->value;
56 while ((i != j) && ((i->value) <= tmp))
57 {
58 i = (*i).r;
59 }
60 j->value = i->value;
61 }
62 i->value = tmp;
63 return i;
64 }
65
66 void quicksort(struct Element* i, struct Element* j)
67 {
68 if (i != j)
69 {
70 Element* m = i;
71 Element* n = j;
72 Element* middlep;
73 Element* middler;
74 Element* middle = qsort(m, n);
75 if (middle != i) //关键部分：因为是双链表，所以不可middle不可是两端，否则越界出现死循环。
76 {
77 middlep = middle->p;
78 quicksort(i, middlep);
79 }
80 if (middle != j) //关键部分：因为是双链表，所以不可middle不可是两端，否则越界出现死循环。
81 {
82 middler = middle->r;
83 quicksort(middler, j);
84 }
85 }
86 else
87 return;
88
89 }
90
91
92 void main(){
93
94
95 dll* t;
96 t = (int *)malloc(20 * sizeof(int));
97 t->size = 0;
98 init(t, 30);
99 add(t, 6);
100 add(t, 2);
101 add(t, 5);
102 add(t, 56);
103 add(t, 36);
104 add(t, 9);
105 add(t, 98);
106 Element* s = t->head;
107 quicksort(t->head, (t->head)->p);
108 for (int i = 0; i<(t->size); i++){
109 printf("%d\n", s->value);
110 s = s->r;
111 }
112 system("pause");
113
114 }
