复习一下链表反转

分别用递归的方法和非递归的方法实现。

链表反转中通过借助辅助參数，能够用两个指针完毕反转 Node* Reverse2Point(List* head)

#include <stdio.h>
#include <malloc.h>typedef int ElemType;
typedef struct Node {int data;struct Node* next;
}Node, *List;
//用数组arr来初始化链表中数据；此例中链表无头点
int InitList(List *list, ElemType* arr, int num)
{int i= 0;Node* tail_node; Node* tmp_node;*list =(List)malloc(sizeof(Node));if(NULL == *list)return;(*list)->data = arr[i];(*list)->next = NULL;tail_node = *list;for(i = 1; i < num; i++) {tmp_node = (Node*)malloc(sizeof(Node));if(NULL == tmp_node)return;tmp_node->data = arr[i];tmp_node->next = NULL;tail_node->next = tmp_node;tail_node = tmp_node; }
}   void TraveseList(List list)
{Node* tmp_node;if(NULL == list)return;tmp_node = list;while(tmp_node) {printf("%d ", tmp_node->data);tmp_node = tmp_node->next;}printf("\n");
}void ReverseList(List* list)
{Node* p_pre = NULL;Node* p_cur = NULL;Node* p_nxt = NULL;if(NULL == list)return;p_cur = (*list)->next;p_pre = *list;p_pre->next = NULL;while(p_cur) {p_nxt = p_cur->next;p_cur->next = p_pre;p_pre = p_cur;p_cur = p_nxt;}*list = p_pre;
}Node* Reverse2Point(List* head)
{Node* p_cur = NULL;Node* p_nxt = NULL;if(NULL == *head)return;p_cur = (*head)->next;(*head)->next = NULL;while(p_cur) {p_nxt = p_cur->next;p_cur->next = *head;*head = p_cur;p_cur = p_nxt;}
}
//递归实现反转，返回反转后的链表头
//原理同上述非递归方法。反转当前节点和该节点的指针（反转前分别保存当前节点和该节点的下一个节点。以便完毕兴许节点同样的操作--通过递归完毕）
Node* Reverse(Node* p_cur, Node* p_pre)
{if(NULL == p_cur->next) {p_cur->next = p_pre;return p_cur;}else {Node *p_nxt = p_cur->next;p_cur->next = p_pre;Reverse(p_nxt, p_cur);}
}int main()
{List head;Node* tmp;int array[] = {3, 5, 7, 8, 2};InitList(&head, array, 5);TraveseList(head);printf("reverse list:");ReverseList(&head);TraveseList(head);printf("reverse list:");head = Reverse(head, NULL);TraveseList(head);printf("reverse list:");Reverse2Point(&head);TraveseList(head);return 0;
}