Write routines to implement two stacks using only one array. Your stack routines should not declare an overflow unless every slot in the array is used.
Format of functions:
Stack CreateStack( int MaxElements );
int IsEmpty( Stack S, int Stacknum );
int IsFull( Stack S );
int Push( ElementType X, Stack S, int Stacknum );
ElementType Top_Pop( Stack S, int Stacknum );
where int Stacknum
is the index of a stack which is either 1 or 2; int MaxElements
is the size of the stack array; and Stack
is defined as the following:
typedef struct StackRecord *Stack;
struct StackRecord {
int Capacity; /* maximum size of the stack array */
int Top1; /* top pointer for Stack 1 */
int Top2; /* top pointer for Stack 2 */
ElementType *Array; /* space for the two stacks */
}
Note: Push
is supposed to return 1 if the operation can be done successfully, or 0 if fails. If the stack is empty, Top_Pop
must return ERROR
which is defined by the judge program.
Sample program of judge:
#include <stdio.h>
#include <stdlib.h>
#define ERROR 1e8
typedef int ElementType;
typedef enum { push, pop, end } Operation;
typedef struct StackRecord *Stack;
struct StackRecord {
int Capacity; /* maximum size of the stack array */
int Top1; /* top pointer for Stack 1 */
int Top2; /* top pointer for Stack 2 */
ElementType *Array; /* space for the two stacks */
};
Stack CreateStack( int MaxElements );
int IsEmpty( Stack S, int Stacknum );
int IsFull( Stack S );
int Push( ElementType X, Stack S, int Stacknum );
ElementType Top_Pop( Stack S, int Stacknum );
Operation GetOp(); /* details omitted */
void PrintStack( Stack S, int Stacknum ); /* details omitted */
int main()
{
int N, Sn, X;
Stack S;
int done = 0;
scanf("%d", &N);
S = CreateStack(N);
while ( !done ) {
switch( GetOp() ) {
case push:
scanf("%d %d", &Sn, &X);
if (!Push(X, S, Sn)) printf("Stack %d is Full!\n", Sn);
break;
case pop:
scanf("%d", &Sn);
X = Top_Pop(S, Sn);
if ( X==ERROR ) printf("Stack %d is Empty!\n", Sn);
break;
case end:
PrintStack(S, 1);
PrintStack(S, 2);
done = 1;
break;
}
}
return 0;
}
/* Your function will be put here */
Sample Input:
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
Sample Output:
Stack 2 is Empty!
Stack 1 is Full!
Pop from Stack 1: 1
Pop from Stack 2: 13 12 11
代码:
Stack CreateStack( int MaxElements )
{
Stack p = (Stack)malloc(sizeof(struct StackRecord));
p -> Array = (int *)malloc(sizeof(MaxElements));
p -> Capacity = MaxElements;
p -> Top1 = -;
p -> Top2 = MaxElements;
return p;
}
int IsEmpty( Stack S, int Stacknum )
{
if(Stacknum == )
{
if(S -> Top1 == -)return ;
return ;
}
else
{
if(S -> Top2 == S -> Capacity)return ;
return ;
}
}
int IsFull( Stack S )
{
if(S -> Top2 - S -> Top1 == )return ;
return ;
}
int Push( ElementType X, Stack S, int Stacknum )
{
if(IsFull(S))return ;
if(Stacknum == )S -> Array[++ (S -> Top1)] = X;
else S -> Array[-- (S -> Top2)] = X;
return ;
}
ElementType Top_Pop( Stack S, int Stacknum )
{
if(IsEmpty(S,Stacknum))return ERROR;
if(Stacknum == )return S -> Array[(S -> Top1) --];
else return S -> Array[(S -> Top2) ++];
}