反转单链表-常数附加空间且O(N)时间

Posted 2020-08-01 clairvoyant

反转链表光是O(N)要求可以先存入数组再从尾部读入单链表。

若是要求常数附件空间，代码如下：

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 
 4 typedef struct node Node;
 5 typedef struct node List;
 6 struct node {
 7     int item;
 8     Node* Next;
 9 };
10 
11 List ReverseList(List* list)
12 {
13     Node* TempNode = list;
14     Node* PrevNode = NULL;
15     Node* NextNode = list->Next;
16     
17     while (NextNode != NULL) {
18         TempNode->Next = PrevNode;
19         PrevNode = TempNode;
20         TempNode = NextNode;
21         NextNode = NextNode->Next;
22     }
23     TempNode->Next = PrevNode;
24     return TempNode;
25 }