Linked list in situ reverse order
Topic information
Please write a function void inverse( LinkList )
to realize the in-situ inversion of the singly linked list.
That is to use the original node to L =(a1, a2, …… , an)
transform the linear table: into:L =( an, …… , a2, a1)
Pre-code:
#include <iostream>
using namespace std;
typedef int ElemType;
typedef struct node
{
ElemType data;
struct node * next;
} NODE;
typedef NODE * LinkList;
void output( LinkList );
void change( int, int, NODE * );
LinkList createList( ElemType );
void inverse( LinkList );
LinkList createList( ElemType finish ) //finish:数据结束标记
{
ElemType x;
NODE *newNode;
LinkList first = new NODE; // 建立头结点
first->next = NULL;
first->data = finish;
cin >> x; // 约定以finish结束连续输入
while ( x != finish )
{
newNode = new NODE; // 建立新结点
newNode->data = x;
newNode->next = first->next; // ①
first->next = newNode; // ②
cin >> x;
}
return first;
}
void output( LinkList head )
{
cout << "List:";
while ( head->next != NULL )
{
cout << head->next->data << ",";
head = head->next;
}
cout << endl;
}
int main(int argc, char** argv)
{
LinkList head;
head = createList( -1 );
output( head );
inverse( head );
output( head );
return 0;
}
Test input | Expect output | |
---|---|---|
Test case 1 | 10 20 30 40 -1 |
List:40,30,20,10, List:10,20,30,40, |
Test case 2 | 10 -1 |
List:10, List:10, |
answer
void inverse(LinkList head)
{
LinkList p = head->next;
head->next = NULL;
while (p != NULL)
{
LinkList succ = p->next;
p->next = head->next;
head->next = p;
p = succ;
}
}