資料結構與演算法——在一個陣列中實現兩個堆疊（C語言）

要求在一個陣列中實現兩個堆疊。

函式介面定義：

Stack CreateStack( int MaxSize );
bool Push( Stack S, ElementType X, int Tag );
ElementType Pop( Stack S, int Tag );
其中Tag是堆疊編號，取1或2；MaxSize堆疊陣列的規模；Stack結構定義如下：

typedef int Position;
struct SNode {
ElementType *Data;
Position Top1, Top2;
int MaxSize;
};
typedef struct SNode *Stack;
注意：如果堆疊已滿，Push函式必須輸出“Stack Full”並且返回false；如果某堆疊是空的，則Pop函式必須輸出“Stack Tag Empty”（其中Tag是該堆疊的編號），並且返回ERROR。

裁判測試程式樣例：

#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;
}

/* 你的程式碼將被嵌在這裡 */

輸入樣例：

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
輸出樣例：

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

【答案】：

Stack CreateStack( int MaxSize )
{

    Stack L = (Stack)malloc(sizeof(struct SNode));
    L->Data =(ElementType*)malloc(sizeof(ElementType)*MaxSize);
    L->Top1 = -1;
    L->Top2 = MaxSize;
    L->MaxSize = MaxSize;
    return L;
}

bool Push(Stack S,ElementType X,int Tag){
    if (S->Top1==S->Top2-1){
        printf("Stack Full\n");
        return false;
    }
    if(Tag==1)
        S->Data[++S->Top1] = X;   //Data裡面的Top1,Top2是S結構體裡面的，不能大意
    else
        S->Data[--S->Top2] = X;
    return true;
}

ElementType Pop(Stack S,int Tag){
    if(Tag==1){
        if(S->Top1==-1){
        printf("Stack %d Empty\n",Tag);
        return ERROR;
}
    else
        return S->Data[S->Top1--];
}
    else if(S->Top2==S->MaxSize){
        printf("Stack %d Empty\n",Tag);
        return ERROR;
}
    else return S->Data[S->Top2++]; 
}