习题2.3

已知两个链表A和B分别表示两个集合，其元素递增排列。请设计一个算法，用于求出A与B的交集,并存放在A链表中。

实现函数：

	void Intersection(LinkList &La, LinkList &Lb, LinkList &Lc)
	{
		
		LNode *pa,*pb,*pc,*p,*r;
		p=new LNode;
		r=new LNode;

		InitList(pa);
		InitList(pb);
		InitList(pc);

		pa=La->next;
		pb=Lb->next;

		Lc = pc = La;
		while(pa&&pb)
		{
			if(pa->data==pb->data)
			{
				pc->next=pa;
				pc=pa;
				pa=pa->next;
				r=pb;pb=pb->next;
				delete r;
			}
			else if(pa->data<pb->data)
			{
				r=pa;
				pa=pa->next;
				delete r;
			}
			else{
				r=pb;pb=pb->next;
				delete r;
			}
		}
		while(pa)
		{
			r=pa;
			pa=pa->next;
			delete r;
		}
		while(pb)
		{
			r=pb;
			pb=pb->next;
			delete r;
		}
		pc->next=NULL;
		delete Lb;
		}

完整代码：

#include <iostream>
#include <stdlib.h>
using namespace std;

typedef int Status;
#define OK 1
#define ERROR 0
#define OVERFLOW -2

typedef struct LNode
{
	int data;
	struct LNode *next;
}LNode,*LinkList;

Status InitList(LinkList &L);
Status CreateList_T(LinkList &L,int n);
Status printList(LinkList L);
void Intersection(LinkList &La, LinkList &Lb, LinkList &Lc);

int main()
{
	int n;
	LinkList La;	
	LinkList Lb;
	InitList(La);
	InitList(Lb);
	LinkList Lc;
	InitList(Lc);
	cout<<"请输入n，然后输入n个非递减元素,创建La"<<endl;
cin>>n;

	CreateList_T(La,n);
cout<<"请输入n，然后输入n个非递减元素,创建Lb"<<endl;
cin>>n;

	CreateList_T(Lb,n);

cout<<"合并后的Lc为："<<endl;
Intersection(La,Lb,Lc);
printList(Lc);
system("pause");
return 0;
}

Status InitList(LinkList &L)
{
	L=new LNode;
	L->next=NULL;
	return OK;
}

Status CreateList_T(LinkList &L,int n)
{
	int i=0;
	LNode *p;
	LNode *r;
	r=L;

	while(1)
	{
		p=new LNode;
    	cin>>p->data;
		p->next=NULL;
		r->next=p;
		r=p;
		i++;
		if(i==n) break;
		


	}
	return OK;
}

Status printList(LinkList L)
{
	LNode *p;
	if(!L) return ERROR;
	p=new LNode;
	p=L->next;
	while(1)
	{   
		cout<<p->data;
		cout<<" ";
		p=p->next;
		if(p==NULL) break;

	}
	cout<<endl;
	
	return OK;
}

	void Intersection(LinkList &La, LinkList &Lb, LinkList &Lc)
	{
		
		LNode *pa,*pb,*pc,*p,*r;
		p=new LNode;
		r=new LNode;

		InitList(pa);
		InitList(pb);
		InitList(pc);

		pa=La->next;
		pb=Lb->next;

		Lc = pc = La;
		while(pa&&pb)
		{
			if(pa->data==pb->data)
			{
				//pc->next=pa;
				pc=pa;
				pa=pa->next;
				r=pb;pb=pb->next;
				delete r;
			}
			else if(pa->data<pb->data)
			{
				r=pa;
				pa=pa->next;
				delete r;
			}
			else{
				r=pb;pb=pb->next;
				delete r;
			}
		}
		while(pa)
		{
			r=pa;
			pa=pa->next;
			delete r;
		}
		while(pb)
		{
			r=pb;
			pb=pb->next;
			delete r;
		}
		pc->next=NULL;
		delete Lb;
		}