线性表--算法设计题2.25

假设以两个元素依值递增有序排列的线性表A和B分别表示两个集合（即同一表中的元素值各不相同），现要求另辟空间构成一个线性表C，其元素为A和B中元素的交集，且表C中的元素有依值递增有序排列。试对顺序表编写求C的算法。

 C code：

#include < stdio.h >
#include < stdlib.h >
#define  LIST_INIT_SIZE 10
#define  LIST_INCREMENT 2
#define  ERROR 0
#define  OK 1
#define  OVERFLOW -1
#define  TRUE 1
typedef  int  Status;

struct  SqList
{
      int   * elem;
      int  length;
      int  listsize;
};

void  InitList(SqList  & L)
{
     L.elem = ( int * )malloc(LIST_INIT_SIZE * sizeof ( int ));
      if ( ! L.elem)
       exit(OVERFLOW);
     L.length = 0 ;
     L.listsize = LIST_INIT_SIZE;
}

Status ListInsert(SqList  & L, int  i, int  e)
{
      int   * newbase, * q, * p;
      if (i < 1 || i > L.length + 1 )
        return  ERROR;
      if (L.length == L.listsize)
     {
          newbase = ( int * )realloc(L.elem,(L.listsize + LIST_INCREMENT) * sizeof ( int ));
           if ( ! newbase)
            exit(OVERFLOW);
          L.elem = newbase;
          L.listsize += LIST_INCREMENT;
         
        }
        q = L.elem + i - 1 ;
         for (p = L.elem + L.length - 1 ; p >= q;  -- p)
           * (p + 1 ) =* p;
         * q = e;
         ++ L.length;
         return  OK;
}

void  CreateList(SqList  & L, int  len)
{
      int  i,t;
     printf( " Please input elems:  " );
      for (i = 1 ; i <= len; i ++ )
     { 
       scanf( " %d " , & t);
          ListInsert(L,i,t); 
        }
}

void  ListTraverse(SqList L, void ( * vist)( int & ))
{
      int   * p = L.elem;
      int  i;
      for (i = 1 ; i <= L.length; i ++ )
     {
          vist( * p ++ );
        }
        printf( " \n " );
}

void  print1( int   & c)
{
     printf( " %d  " ,c);
}

int  cmp( const   void   * a, const   void   * b)
{
      return   * ( int * )a  -   * ( int * )b;
}

void  ListSort(SqList  & L)
{
  qsort(L.elem,L.length, sizeof ( int ),cmp);    
    
}

void  CreateList_C(SqList La,SqList Lb,SqList  & Lc)
{
      int  i = 0 ,j = 0 ,k = 1 ;
      while (i < La.length  &&  j < Lb.length)
     {
           if (La.elem[i] < Lb.elem[j])
      i ++ ;
     else
    {
          if (La.elem[i] > Lb.elem[j])
           j ++ ;
          else
         {
              ListInsert(Lc,k,La.elem[i]);
              i ++ ;
              k ++ ;
            }
       }         
        }
}

int  main()
{
     SqList La,Lb,Lc;
     InitList(La);
     InitList(Lb);
     InitList(Lc);
      int  La_len,Lb_len;
     printf( " input length of La:  " );
     scanf( " %d " , & La_len);
     printf( " input length of Lb:  " );
     scanf( " %d " , & Lb_len);
     CreateList(La,La_len);
     CreateList(Lb,Lb_len); 
     printf( " List a:  " );
     ListTraverse(La,print1);
     printf( " List b:  " );
     ListTraverse(Lb,print1);
     printf( " After sorting List a:  " );
     ListSort(La);
     ListTraverse(La,print1);
     printf( " After sorting List b:  " );
     ListSort(Lb);
     ListTraverse(Lb,print1);
     CreateList_C(La,Lb,Lc);
     printf( " List c:  " );
     ListTraverse(Lc,print1);
      return   0 ;

}