数据结构C语言版（清华大学

//数据结构C语言版（清华大学_唐国民_第3版）
//循环链表,书 P38 例子2.5.2 三元多项式加法，与书上代码有些许出入，不用在意，重要的是思路
//多项式按指数降序排序，这里的降序排序是指x,y,z分别对应的指数i,j,k,按i*100+j*10+k的和来降序排序
#include 
#include 

typedef struct LNode* List;
struct LNode{
	int coef;
	int index;
	List Next;
};

List Create(List );
void Add(List,List);
void Printout(List);

int main()
{
	List Ptrl_p,Ptrl_q;
	Ptrl_p=Create(Ptrl_p);
	Ptrl_q=Create(Ptrl_q);
	Add(Ptrl_p,Ptrl_q);
	Printout(Ptrl_q);
	return 0;
}

List Create(List Ptrl)
{
	int n,i;
	List Pre,Cur;
	Ptrl=(List)malloc(sizeof(struct LNode));
	Pre = Ptrl;
	Ptrl->coef=0;
	Ptrl->index=-1;
	printf("How many numbers dou you want to create?  ");
	fflush(stdin);
	scanf("%d",&n);
	for(i=1;i<=n;++i){
		List Cur=(List)malloc(sizeof(struct LNode));
		printf("The %dth's coef is:t",i);
		fflush(stdin);
		scanf("%d",&Cur->coef);
		printf("The %dth's xyz index is:t",i);
		fflush(stdin);
		scanf("%d",&Cur->index);
		Pre->Next=Cur;
		Cur->Next=Ptrl;
		Pre=Cur;
	}
	return Ptrl;
}

void Add(List Ptrl_p,List Ptrl_q)
{
	
	List p,q,Pre_q,Crea_q;
	p=Ptrl_p->Next;
	q=Ptrl_q->Next;
	Pre_q=Ptrl_q;
	while(p->index != -1){
		while(p->index < q->index){
			q=q->Next;
			Pre_q=Pre_q->Next;
		}
		if(p->index==q->index){
			q->coef=p->coef + q->coef;
			if(q->coef == 0){
				Pre_q->Next = q->Next;
				free(q);
				q=Pre_q->Next;
				p=p->Next;
			}
			else{
				p=p->Next;
				q=q->Next;
				Pre_q=Pre_q->Next;
			}
		}
		else{
			Crea_q=(List)malloc(sizeof(struct LNode));
			Crea_q->coef=p->coef;
			Crea_q->index=p->index;
			Pre_q->Next=Crea_q;
			Crea_q->Next=q;
			p=p->Next;
			Pre_q=Pre_q->Next;
		}
	}
}

void Printout(List Ptrl_q){
	int i=0;
	List Rear=Ptrl_q->Next;
	while(Rear->index != -1){
		i++;
		printf("The %dth: coef is %dt index of xyz is %dn",i,Rear->coef,Rear->index);
		Rear=Rear->Next;
	}
}