我想在Linklist中交换节点。
我编写了函数swap，但它在节点旁边的节点上不起作用。
例如，我想交换node4和node5。这是错误的。
void swap (int pos1, int pos2, LINK *head)
{
LINK* pre_node1 = search(pos1-1, head);
LINK* pre_node2 = search(pos2-1, head);
LINK* current_node1 = pre_node1 -> next;
LINK* current_node2 = pre_node2 -> next;
LINK* next_node1 = search(pos1+1, head);
LINK* next_node2 = search(pos2+1, head);
pre_node1 -> next = current_node2;
pre_node2 -> next = current_node1;
current_node1 -> next = next_node2;
current_node2 -> next = next_node1;
}
我测试了这个功能：
for (int i=1; i < 10; i++)
insert(i,head,i);
printf ("original array: \n");
print(head);
printf ("swap node2 and node7: \n");
swap(2,7,head);
print(head);
printf ("swap node1 and node9: \n");
swap(1,9,head);
print(head);
/*
It does not work!
swap(4,5,head);
print(head);
*/
我可以使用swap2交换内容。但我认为这很难看。
void swap2 (int pos1, int pos2, LINK *head)
{
LINK* node1 = search(pos1, head);
LINK* node2 = search(pos2, head);
int tem = node1->data;
node1->data = node2->data;
node2->data = tem;
}
我想交换节点。请告诉我如何更正swap。
以下是我的代码：
#include <stdio.h>
#include <stdlib.h>
typedef struct linklist {
int data;
struct linklist * next;
}LINK;
LINK* createnode (int element,LINK *first);
LINK* search (int j,LINK *head);
void insert (int ele, LINK *head, int pos);
void delete (LINK *head, int pos);
void print (LINK *head);
void swap (int pos1, int pos2, LINK *head);
void swap2 (int pos1, int pos2, LINK *head);
void swap3(int i,int j,LINK *head);
int main(int argc, char ** argv)
{
LINK *head;
head = (LINK *)malloc(sizeof(LINK));
head-> next = NULL;
for (int i=1; i < 10; i++)
insert(i,head,i);
printf ("original array: \n");
print(head);
printf ("swap node2 and node7: \n");
swap(2,7,head);
print(head);
printf ("swap node1 and node9: \n");
swap(1,9,head);
print(head);
/*
It does not work!
swap(4,5,head);
print(head);
*/
/*
The function swap2 only swap the data, I want swap the nodes.
printf ("swap node4 and node5: \n");
swap2(4,5,head);
print(head);
*/
printf ("swap node4 and node5: \n");
swap3(4,5,head);
print(head);
}
LINK* createnode(int element,LINK *first)
{
LINK *ele;
ele = (LINK *)malloc(sizeof(LINK));
ele -> data = element;
ele -> next = first -> next;
first -> next = ele;
return first;
}
LINK* search (int j,LINK * head)
{
LINK *tem;
tem = head;
int i = 0;
while (tem -> next !=NULL && i < j)
{
tem = tem->next;
i++;
}
if (tem != NULL && i==j)
return tem;
else return NULL;
}
void insert (int ele, LINK *head, int pos)
{
LINK *prenode = search(pos-1,head);
LINK *d = createnode(ele, prenode);
if (prenode == NULL)
printf ("insert error! \n");
}
void delete (LINK *head, int pos)
{
LINK *prenode = search (pos-1,head);
if (prenode != NULL)
{
LINK *nownode = prenode -> next;
prenode -> next = nownode -> next;
free(nownode);
}
else printf("delete error!\n");
}
void print (LINK* head)
{
int j=0;
LINK *p;
p = head->next;
while (p != NULL)
{
printf("%d ", p->data);
p = p -> next;
j++;
}
printf ("\n");
}
void swap (int pos1, int pos2, LINK *head)
{
LINK* pre_node1 = search(pos1-1, head);
LINK* pre_node2 = search(pos2-1, head);
LINK* current_node1 = pre_node1 -> next;
LINK* current_node2 = pre_node2 -> next;
LINK* next_node1 = search(pos1+1, head);
LINK* next_node2 = search(pos2+1, head);
pre_node1 -> next = current_node2;
pre_node2 -> next = current_node1;
current_node1 -> next = next_node2;
current_node2 -> next = next_node1;
}
void swap2 (int pos1, int pos2, LINK *head)
{
LINK* node1 = search(pos1, head);
LINK* node2 = search(pos2, head);
int tem = node1->data;
node1->data = node2->data;
node2->data = tem;
}
void swap3(int i,int j,LINK *head)
{
LINK* previous_i = search(i-1,head);
LINK* previous_j = search(j-1,head);
LINK* adress_i = search(i,head);
LINK* adress_j = search(j,head);
LINK* latter_i = search(i+1,head);
LINK* latter_j = search(j+1,head);
if (adress_i->next != adress_j && adress_j->next != adress_i)
{
previous_i -> next = adress_j;
adress_j -> next = latter_i;
previous_j -> next = adress_i;
adress_i -> next = latter_j;
}
else if (adress_i->next == adress_j)
{
previous_i -> next = adress_j;
adress_j -> next = adress_i;
adress_i ->next = latter_j;
}
else if (adress_j->next == adress_i)
{
previous_j -> next = adress_i;
adress_i -> next = adress_j;
adress_j ->next = latter_i;
}
}
最后，我写了swap3。但我觉得它太复杂了。这是对的。
void swap3(int i,int j,LINK *head)
{
LINK* previous_i = search(i-1,head);
LINK* previous_j = search(j-1,head);
LINK* adress_i = search(i,head);
LINK* adress_j = search(j,head);
LINK* latter_i = search(i+1,head);
LINK* latter_j = search(j+1,head);
if (adress_i->next != adress_j && adress_j->next != adress_i)
{
previous_i -> next = adress_j;
adress_j -> next = latter_i;
previous_j -> next = adress_i;
adress_i -> next = latter_j;
}
else if (adress_i->next == adress_j)
{
previous_i -> next = adress_j;
adress_j -> next = adress_i;
adress_i ->next = latter_j;
}
else if (adress_j->next == adress_i)
{
previous_j -> next = adress_i;
adress_i -> next = adress_j;
adress_j ->next = latter_i;
}
}
提前致谢。
答案 0 :(得分：0)
我想有更简洁的方法可以解决这个问题，但这是我的两分钱： 测试：
swap(2,7,head);
swap(1,9,head);
swap(4,5,head);
swap(6,5,head);
void swap (int pos1, int pos2, LINK *head)
{
LINK* pre_node1 = search(pos1-1, head);
LINK* pre_node2 = search(pos2-1, head);
LINK* current_node1 = pre_node1 -> next;
LINK* current_node2 = pre_node2 -> next;
LINK* next_node1 = search(pos1+1, head);
LINK* next_node2 = search(pos2+1, head);
pre_node1 -> next = current_node2;
pre_node2->next = current_node1;
if (current_node1 != next_node2)
current_node1 -> next = next_node2;
else
current_node1 -> next = current_node2;
if (current_node2 != next_node1)
current_node2->next = next_node1;
else
current_node2->next = current_node1;
}