flag4给出俩个单向链表的头指针，比如pA，pB，判断这俩个链表是否相交

//给出俩个单向链表的头指针，比如pA，pB，判断这俩个链表是否相交
# include <stdio.h>
# include <malloc.h>
# include <math.h>
typedef struct node
{
int data;
struct node* next;
}Node,*Pnode;
Pnode creatnode();
void travel(Pnode L);
int leng(Pnode L);
bool compare(Pnode pA,Pnode pB);
void main()
{
Pnode pA,pB;
pA=creatnode();//创建pA
pB=creatnode();//创建pB


//travel(pA);
//travel(pB);
printf("number=%d\n",leng(pA));
if(compare(pA,pB))//如果相同输出OK 否则输出fail


printf("OK");
else
printf("fail");


}
Pnode creatnode()
{
int a,i;
Pnode L=(Pnode)malloc(sizeof(Node));
L->next=NULL;
printf("input your number\n");
scanf("%d",&a);
Pnode ptail=L;
for(i=0;i<a;i++)
{
Pnode pnew=(Pnode)malloc(sizeof(Node));
scanf("%d",&(pnew->data));
pnew->next=NULL;
ptail->next=pnew;
ptail=pnew;
}
return L;
}
void travel(Pnode L)
{
Pnode phead=L->next;
while(NULL!=phead)
{
printf("%d\n",phead->data);
phead=phead->next;
}
}
int leng(Pnode L)
{
int i=0;
Pnode phead=L->next;
while(L!=NULL)
{
i++;
L=L->next;
}
return i;
}
bool compare(Pnode pA,Pnode pB)
{
int i;
int a=leng(pA)-leng(pB);
Pnode Ahead=pA->next;
Pnode Bhead=pB->next;
for(i=0;i<a;i++)//核心 谁长谁先走，这里为了方便假设pA长
{
Ahead=Ahead->next;
}
while(Ahead!=NULL && Bhead!=NULL)
{
if(Ahead->data != Bhead->data)
break;//如果不同 立刻跳出循环体
else
{
Ahead=Ahead->next;
Bhead=Bhead->next;
}
}
if(Ahead==NULL && Bhead==NULL )
return true;
else 
return false;
}