单链表的问题

[ccbbcc]

设计算法：将一个带头结点的单链表A分解为两个带头结点的单链表A和B，使得A表中含有原表中序号为奇数的元素，B表中含有原表中序号为偶数的元素，且保持其相对顺序。
我写了一个程序，可是运行错误，好像内存溢出。请高手指教。谢谢！
#include<stdio.h>
#define uint unsigned int
#define uchar unsigned char
#define N 10 //N为链表中数据元素的个数

struct node
{
int data;
struct node *next;
};
typedef struct node NODE;
NODE *head,*s;
NODE *p1;
NODE *A,*B;
NODE *r,*p,*q;

NODE *creatlink2()
{

NODE *p;
int num;
head=(NODE *)malloc(sizeof(NODE));
scanf("%d",&num);
p=head;
while(num!=0)
{
s=(NODE *)malloc(sizeof(NODE));
s->data=num;
p->next=s;
p=s;
scanf("%d",&num);
}
p->next=NULL;
return head;
}

int length()
{
NODE *p;
int j;
p=head;
j=0;
while(p!=NULL)
{
p=p->next;
j++;
}
return (j-1);
}
void disA()
{

B=(NODE *)malloc(sizeof(NODE)); //建立单链表B的头结点
r=B;
p1=B;

p=head->next;

while((p!=NULL)&&(p->next!=NULL))
{
//r=(NODE *)malloc(sizeof(NODE));
q=p->next;
p->next=q->next;
r->next=q;
r=q;
p=p->next;
}
r->next=NULL;
p->next=NULL;
}
int main()
{
uchar i;
int k;
creatlink2();
/*for(i=0;i<9;i++)
{
head=head->next;
printf("%d\n",head->data);
}*/
k=length();
printf("%d\n",k);
disA();

getchar();
getchar();

return 0;
}

[prajna]

void disA() 你想用這個函數來拆分A鏈表嗎？ 給你設計一個新的函數接口: NODE* displace(NODE* A); 返回的是B鏈表，當然，A鏈表也被修改為含有原表中序号为奇数的元素了。 過一會兒給你一個參考

[ccbbcc]

谢谢！等你的参考。

[prajna]

用split這個名字更好點， 下面的代碼僅供參考思路, 沒測試。 NODE* split(NODE* A) { NODE *B=NULL; NODE *pa=NULL; //pa is the tail of new A NODE *pb=NULL; //pb is the tail of B NODE *p=NULL; //pa is the head of old A if (A) B=p=A->next; else return B; pa = A; pb = B; while (p != NULL){ NODE* pnext = p->next; pa->next = p->next; if (pnext) pb->next = pnext->next; else break; p = pnext->next; pa = pnext; if (p) pb = p; } if (pa) pa->next = NULL; if (pb) pb->next = NULL; return B; }

[topyxu]

看你代码分配了节点空间都没释放，很费空间的。链表没输出。 错误我只看出一点点。 void disA() { B=(NODE *)malloc(sizeof(NODE)); //建立单链表B的头结点 r=B; p1=B; p=head->next; while((p!=NULL)&&(p->next!=NULL)) { //r=(NODE *)malloc(sizeof(NODE)); q=p->next; p->next=q->next; r->next=q; r=q; p=p->next; } r->next=NULL; p->next=NULL; } 出错了，可能要把p->next=NULL; 改成if(p){p->next=NULL;} 举个例子：链表有两个节点1和2 p=head->next指向1，head->next->next指向2，head->next->next->next=NULL; while((p!=NULL)&&(p->next!=NULL))条件成立进入循环 q=p->next;//q指向2 p->next=q->next;//p的下一个元素指向第三个元素即为空 p->next=q->next; r->next=q; r=q; p=p->next;//注意这里即是p=NULL了 结束循环做 p->next=NULL; 即是NULL->next=NULL出错 错误只要是空指针指向空指针 没测试过。。。仅供参考

[prajna]

幫你改好了,你自己慢慢消化吧,不懂儘管問

#include<stdio.h>
#include <stdlib.h>
#define uint unsigned int
#define uchar unsigned char
#define N 10           //N为链表中数据元素的个数

struct node
{
       int data;
       struct node *next;
};
typedef struct node NODE;
NODE *head,*s;
NODE *p1;
NODE *A,*B;
NODE *r,*p,*q;

NODE *creatlink2()
{
     
     NODE *p=NULL;
     int num;
     //head=(NODE *)malloc(sizeof(NODE));
     head = NULL;
     scanf("%d",&num);
     while(num!=0)
     {
          s=(NODE *)malloc(sizeof(NODE));
          s->data=num;
          if (p) p->next=s;
          p = s;

          if (head==NULL) head = p;
          scanf("%d",&num);
     } 
     p->next=NULL;
     return head;
}
void deletelink(NODE* lnk)
{
  NODE *p = lnk;
  while (p) {
    NODE* t = p;
    p=p->next;
    free(t);
  }
}

int length()
{
    NODE *p;
    int j;
    p=head;
    j=0;
    while(p!=NULL)
    {
         p=p->next;
         j++;
    }
    return (j-1);
}
NODE* split(NODE* A)
{
  NODE *B=NULL;
  NODE *pa=NULL; //pa is the tail of new A
  NODE *pb=NULL; //pb is the tail of B
  NODE *p=NULL; //pa is the head of old A
  if (A) B=p=A->next;
  else return B;
  pa = A;
  pb = B;
  while (p != NULL){
    NODE* pnext = p->next;
    pa->next = p->next;
    if (pnext) pb->next = pnext->next;
    else break;

    p = pnext->next;
    pa = pnext;
    if (p) pb = p;
  }
  if (pa) pa->next = NULL;
  if (pb) pb->next = NULL;

  return B;
}
void prtlink(NODE*lnk)
{
  NODE *p = lnk;
  while (p) {
    printf("%d, ",p->data);
    p=p->next;
  }
}
int main()
{
    uchar i;
    int k;
    NODE*A = creatlink2();
    NODE*B=NULL;
prtlink(A);    
printf("\n");

    //k=length();
    //printf("%d\n",k);
    //disA();
    B=split(A);

    prtlink(A);
    printf("\n");
    prtlink(B);

    deletelink(A);
    deletelink(B);

    getchar();
   
return 0;
}