求两个有序单链表的并交集

求并集————————————————————————————

#include <iostream>

#include "./List.h"//利用我们自己实现的单链表List

using namespace std;



void PrintList(List L)

{

     if(NULL == L) return;

     Position pos = First(L);

     cout<<"List L:";

     while(NULL != pos)

     {

          cout<<Retrieve(pos)<<"->";

          pos = pos->next;

     }

     cout<<"NULL"<<endl;;

}

List UnionOfTwoLists(List list1, List list2)

{

     if(NULL == list1  && NULL == list2) return NULL;

     Position p1 = First(list1), p2 = First(list2);

     List out = CreateEmptyList();

     while(NULL != p1 && NULL != p2)

     {

          if(Retrieve(p1) <= Retrieve(p2))

          {

               PushBack(Retrieve(p1), out);

               p1 = p1->next;

          }

          else

          {

               PushBack(Retrieve(p2), out);

               p2 = p2->next;

          }

     }

     if(NULL == p1)

     {

          while(NULL != p2)

          {

               PushBack(Retrieve(p2), out);

               p2 = p2->next;

          }

     }

     else if(NULL == p2)

     {

          while(NULL != p1)

          {

               PushBack(Retrieve(p1), out);

               p1 = p1->next;

          }

     }

     return out;

}

int main(int argc, char const *argv[])

{

     List list1 = CreateEmptyList();

     List list2 = CreateEmptyList();

     for (int i = 0; i < 10; ++i)

          PushBack(i, list1);

     for (int i = 0; i < 20; i += 2)

          PushBack(i, list2);

     PrintList(list1);

     PrintList(list2);

     List res = UnionOfTwoLists(list1, list2);

     PrintList(res);

     return 0;

}

　　

求交集——————————————————————————————

#include <iostream>

#include "./List.h"//利用我们自己实现的单链表List

using namespace std;



void PrintList(List L)

{

     if(NULL == L) cout<<"Error List L is NULL!!!"<<endl;

     Position pos = First(L);

     cout<<"List L:";

     while(NULL != pos)

     {

          cout<<Retrieve(pos)<<"->";

          pos = pos->next;

     }

     cout<<"NULL"<<endl;;

}

List IntersectionOfTwoLists(List list1, List list2)

{

     if(NULL == list1  && NULL == list2) return NULL;

     Position p1 = First(list1);

     List out = CreateEmptyList();

     while(NULL != p1)

     {

          Position tmp = Find(Retrieve(p1), list2);

          if(NULL != tmp)

               PushBack(Retrieve(tmp), out);

          p1 = p1->next;

     }

     return out;

}

int main(int argc, char const *argv[])

{

     List list1 = CreateEmptyList();

     List list2 = CreateEmptyList();

     for (int i = 0; i < 20; ++i)

          PushBack(i, list1);

     for (int i = 0; i < 20; i += 2)

          PushBack(i, list2);

     PrintList(list1);

     PrintList(list2);

     List res = IntersectionOfTwoLists(list1, list2);

     PrintList(res);

     return 0;

}