4-7 在一个数组中实现两个堆栈

本题要求在一个数组中实现两个堆栈。

函数接口定义：

Stack CreateStack( int MaxSize );
bool Push( Stack S, ElementType X, int Tag );
ElementType Pop( Stack S, int Tag );

其中

Tag

是堆栈编号，取1或2；

MaxSize

堆栈数组的规模；

Stack

结构定义如下：

typedef int Position;
struct SNode {
ElementType *Data;
Position Top1, Top2;
int MaxSize;
};
typedef struct SNode *Stack;

注意：如果堆栈已满，

Push

函数必须输出“Stack Full”并且返回false；如果某堆栈是空的，则

Pop

函数必须输出“Stack Tag Empty”（其中Tag是该堆栈的编号），并且返回ERROR。

裁判测试程序样例：

#include <stdio.h>
#include <stdlib.h>

#define ERROR 1e8
typedef int ElementType;
typedef enum { push, pop, end } Operation;
typedef enum { false, true } bool;
typedef int Position;
struct SNode {
ElementType *Data;
Position Top1, Top2;
int MaxSize;
};
typedef struct SNode *Stack;
Stack CreateStack( int MaxSize );
bool Push( Stack S, ElementType X, int Tag );
ElementType Pop( Stack S, int Tag );
Operation GetOp();  /* details omitted */
void PrintStack( Stack S, int Tag ); /* details omitted */

int main()
{
int N, Tag, X;
Stack S;
int done = 0;

scanf("%d", &N);
S = CreateStack(N);
while ( !done ) {
switch( GetOp() ) {
case push:
scanf("%d %d", &Tag, &X);
if (!Push(S, X, Tag)) printf("Stack %d is Full!\n", Tag);
break;
case pop:
scanf("%d", &Tag);
X = Pop(S, Tag);
if ( X==ERROR ) printf("Stack %d is Empty!\n", Tag);
break;
case end:
PrintStack(S, 1);
PrintStack(S, 2);
done = 1;
break;
}
}
return 0;
}

/* 你的代码将被嵌在这里 */

输入样例：

5
Push 1 1
Pop 2
Push 2 11
Push 1 2
Push 2 12
Pop 1
Push 2 13
Push 2 14
Push 1 3
Pop 2
End

输出样例：

Stack 2 Empty
Stack 2 is Empty!
Stack Full
Stack 1 is Full!
Pop from Stack 1: 1
Pop from Stack 2: 13 12 11

Stack CreateStack(int MaxSize)
{
/*  in most case I need to use (if or else) to judge the malloc operation whether success or not  */
Stack Sh = (Stack) malloc(sizeof(struct SNode));
Sh->Data = (ElementType *)malloc(sizeof(int) * MaxSize);
Sh->Top1 = -1;
Sh->Top2 = MaxSize;
Sh->MaxSize = MaxSize;
return Sh;
};
bool Push (Stack S, ElementType x, int Tag)
{
if(S == NULL)
return false;
if((S->Top1 + 1 ) == S->Top2)
{
printf("Stack Full\n");
return false;
}
if(1 == Tag)
{
++(S->Top1);
S->Data[ (S->Top1) ] = x;
return true;
}
else if (2 == Tag)
{
--(S->Top2);
S->Data[ (S->Top2) ] = x;
return true;
}
return false;
};
ElementType Pop( Stack S, int Tag )
{
if(S == NULL)
return ERROR;
if(1 == Tag)
{
if(-1 == S->Top1)
{
printf("Stack %d Empty\n", Tag);
return ERROR;
}
return (S->Data[ (S->Top1)-- ]);
}
else if(2 == Tag)
{
if(S->MaxSize == S->Top2)
{
printf("Stack %d Empty\n", Tag);
return ERROR;
}
return ( S->Data[ (S->Top2)++ ]);
}
return ERROR;
};