題目:設有三個帶頭結點的元素按非遞減有序排列的單鏈表A, B, C,對A進行如下操作,使A中僅含有三個表中的交,且沒有值相同的結點,並釋放無用結點。限定時間複雜度爲O( m + n + p ),其中m, n, p分別爲三個表的長度。
/*
* Intersection of three ordered linked lists.
*
* fduan, Dec. 29, 2011.
*/
void intersect_v2( link_list * lst_a, link_list lst_b )
{
node_ptr pa = *lst_a, pb = lst_b->next, p = NULL;
while( pa->next != NULL && pb != NULL )
{
if( pa->next->data < pb->data )
{
p = pa->next;
pa->next = p->next;
free( p );
}
else if( pa->next->data > pb->data )
{
pb = pb->next;
}
else
{
pa = pa->next;
pb = pb->next;
}
}
while( pa->next != NULL )
{
p = pa->next;
pa->next = p->next;
free( p );
}
}
void intersect_triple_lists( link_list * lst_a, link_list lst_b, link_list lst_c )
{
intersect_v2( lst_a, lst_b );
intersect_v2( lst_a, lst_c );
}