pta函数题

双端队列

Push(X,D)：将元素X插入到双端队列D的头

bool Push( ElementType X, Deque D )
{
    if((D->Rear - D->Front + D->MaxSize)%D->MaxSize != D->MaxSize - 1)
    {
        D->Front = (D->Front - 1 + D->MaxSize)%D->MaxSize;
        D->Data[D->Front] = X;
    }
    else return false;
    return true;
}

Pop(D)：删除双端队列D的头元素，并返回

ElementType Pop( Deque D )
{
    if(D->Rear != D->Front)
    {
        ElementType a = D->Data[D->Front];
        D->Front = (D->Front + 1)%D->MaxSize;
        return a;
    }
    else return ERROR;
}

Inject(X,D)：将元素X插入到双端队列D的尾部

bool Inject( ElementType X, Deque D )
{
    if((D->Rear - D->Front + D->MaxSize)%D->MaxSize != D->MaxSize - 1)
    {
        D->Data[D->Rear] = X;
        D->Rear = (D->Rear + 1)%D->MaxSize;
    }
    else return false;
    return true;
}

Eject(D)：删除双端队列D的尾部元素，并返回

ElementType Eject( Deque D )
{
    if(D->Rear != D->Front)
    {
        D->Rear = (D->Rear - 1 + D->MaxSize)%D->MaxSize;
        ElementType a = D->Data[D->Rear];
        return a;
    }
    else return ERROR;
}

堆栈模拟队列

设已知有两个堆栈S1和S2，请用这两个堆栈模拟出一个队列Q。

所谓用堆栈模拟队列，实际上就是通过调用堆栈的下列操作函数:
•int IsFull(Stack S)：判断堆栈S是否已满，返回1或0；
•int IsEmpty (Stack S )：判断堆栈S是否为空，返回1或0；
•void Push(Stack S, ElementType item )：将元素item压入堆栈S；
•ElementType Pop(Stack S )：删除并返回S的栈顶元素。

实现队列的操作，即入队void AddQ(ElementType item)和出队ElementType DeleteQ()。
源代码：

#include<stdio.h>
//#include<algorithm>
#include<stdlib.h>
#include<string.h>

//using namespace std;

struct SNode{
   int num;
   struct SNode * next;
};

typedef struct SNode * STACK;

STACK create()
{
   STACK shead = (STACK)malloc(sizeof(struct SNode));
   shead->next = NULL;
   return shead;
}

void push(STACK S,int number)
{
   STACK snew = (STACK)malloc(sizeof(struct SNode));
   snew->num = number;
   snew->next = S->next;
   S->next = snew;
}

int pop(STACK S)
{
   STACK p;
   int number;
   p = S->next;
   number = p->num;
   S->next = p->next;
   free(p);
   return number;
}

int main(void)
{
   STACK s1 = create();
   STACK s2 = create();
   int n1,n2;
   scanf("%d%d",&n2,&n1);
   int count1 = 0,count2 = 0;
   while(1)
   {
   	char ch;
   	int num;
   	scanf("%c",&ch);
   	if(ch == 'A')
   	{
   		scanf("%d",&num);
   		getchar();
   		if(count1 < n1)
   		{
   			push(s1,num);
   			count1++;
   		}
   		else
   		{
   			printf("ERROR:Full\n");
   		}
   	}
   	else if(ch == 'D')
   	{
   		if(count2 > 0)
   		{
   			printf("%d\n",pop(s2));
   			count2--;
   		}
   		else
   		{
   			printf("ERROR:Empty\n");
   		}
   	}
   	else if(ch =='T')
   	{
   		break;
   	}
   	
   	if(count1 == n1 && count2 == 0)
   	{
   		while(count1 != 0)
   		{
   			push(s2,pop(s1));
   			count1--;
   			count2++;
   		}
   	}
   }	
   return 0;
}