Leetcode 92:反转链表 II

Seawolf

Code:

1. #include <stdio.h>
   
2. 
   
3. struct Node{
   
4. 
   
5.     int val;
   
6. 
   
7.     struct Node *next;
   
8. 
   
9. };
   
10. 
    
11. 
    
12. struct Node * reverseList1(struct Node *hd, int n, int m){
    
13. 
    
14.     int change_len = m - n + 1;
    
15. 
    
16.     struct Node * result = hd;
    
17. 
    
18.     struct Node * pre_head = NULL;
    
19. 
    
20.     while(hd && --n){
    
21. 
    
22.         pre_head = hd;
    
23. 
    
24.         hd = hd->next;
    
25. 
    
26.     }
    
27. 
    
28.     struct Node * modify_node_tail = hd;
    
29. 
    
30.     struct Node * newHead = NULL;
    
31. 
    
32.     while(hd && change_len){
    
33. 
    
34.         struct Node *next = hd->next;
    
35. 
    
36.         hd->next = newHead;
    
37. 
    
38.         newHead = hd;
    
39. 
    
40.         hd = next;
    
41. 
    
42.         change_len = change_len -1;
    
43. 
    
44.     }
    
45. 
    
46.     modify_node_tail->next = hd;
    
47. 
    
48.     if(pre_head){
    
49. 
    
50.         pre_head -> next = newHead;
    
51.     }
    
52.     else{
    
53. 
    
54.         result = newHead;
    
55.     }
    
56. 
    
57. 
    
58.     return result;
    
59. }
    
60. 
    
61. int main(void){
    
62. 
    
63.     struct Node a;
    
64.     struct Node b;
    
65.     struct Node c;
    
66.     struct Node d;
    
67.     struct Node e;
    
68. 
    
69.     a.val = 10;
    
70.     b.val = 20;
    
71.     c.val = 30;
    
72.     d.val = 40;
    
73.     e.val = 50;
    
74. 
    
75.     a.next = &b;
    
76.     b.next = &c;
    
77.     c.next = &d;
    
78.     d.next = &e;
    
79.     e.next = NULL;
    
80. 
    
81.     struct Node * head = &a;
    
82. 
    
83.     while(head){
    
84. 
    
85.         printf("%d\n", head->val);
    
86. 
    
87.         head = head->next;
    
88. 
    
89.     }
    
90. 
    
91.     printf("----------\n");
    
92. 
    
93.     struct Node * head_2 = &a;
    
94. 
    
95.     int x = 2;
    
96. 
    
97.     int y = 4;
    
98. 
    
99.     struct Node *ptr_1 = reverseList1(head_2, x, y);
    
100. 
     
101.     while(ptr_1){
     
102. 
     
103.         printf("%d\n", ptr_1->val);
     
104. 
     
105.         ptr_1 = ptr_1->next;
     
106. 
     
107.     }
     
108. 
     
109.     printf("----------\n");
     
110. 
     
111.     return 0;
     
112. }

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Output:

1. 10
   
2. 20
   
3. 30
   
4. 40
   
5. 50
   
6. ----------
   
7. 10
   
8. 40
   
9. 30
   
10. 20
    
11. 50
    
12. ----------

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