编程实现合并两个有序单链表

Node* Merge2(Node* head1, Node* head2)
{
Node* res,*ret;
if(head1 == NULL) return head2;
if(head2 == NULL) return head1;
Node* p = head1;
Node* q = head2;

if(p->value < q->value)
{
res = p;
p = p->next;
}
else
{
res = q;
q = q->next;
}
ret = res;
while(p && q)
{
if(p->value < q->value)
{
res->next = p;
res = p;
p = p->next;
}
else
{
res->next = q;
res = q;
q = q->next;
}
}
while(p)
{
res->next = p;
res = p;
p = p->next;
}
while(q)
{
res->next = q;
res = q;
q = q->next;
}
return ret;
}