练习3.21 一个数组两个站栈

#include<stdio.h>

#include<stdlib.h>

struct Node;

typedef struct Node *PtrToDStack;



struct Node{

    int top1,top2;

    int Capacity;

    int  *Array;

};



PtrToDStack

CreateStack( int Size )

{

    PtrToDStack s;

    s = malloc( sizeof( struct Node ) );

    s->Array = malloc( sizeof( int ) * Size );

    s->Capacity = Size;

    return s;

}



void

Initial( PtrToDStack s, int k )

{

    if( k = 0 )

        s->top1 = -1;

    else

        s->top2 = s->Capacity;

}



int 

IsEmpty( PtrToDStack s, int k ) 

{

    if( k == 0 )

        return s->top1 == -1;

    else

        return s->top2 == Size;

}



int 

IsFull( PtrToDStack s )

{

    return s->top1 + 1 == s->top2;

}



void

Push( PtrToDStack s, int k, int x )

{

    if( !IsFull( s ) )

    {

        if( k == 0 )

            s->Array[ ++s->top1 ] = x;

        else

            s->Array[ --s->top2 ] = x;

    }

    else

        Error("stack is full");

}



void

Pop( PtrToDStack s, int k )

{

    if( k == 0 )

    {

        if( !IsEmpty( s, 0 ) )

            s->top1--;

        else

            Error("");

    }

    else

    {

        if( !IsEmpty( s, 1 ) )

            s->top2--;

        else

            Error("no ele")

    }

}



int 

Top( PtrToDStack s, int k )

{

    if( k == 0 )

    {

        if( !IsEmpty( s, k ) )

            return s->Array[ s->top1 ];

        else

            Error;

    }

    else

    {

        if( !IsEmpty(s,k) )

            return s->Array[ s->top2 ];

        else

            Error;

    }

}

View Code

个人觉得在Top和Pop处IsEmpty有点冗杂，下次把两个指针都放进一个数组里面top[0],top[1]分别表示左栈和右栈

代码的复用一下就高了

单数组双栈迎面镇长的好处：可以最大化利用数组，减少溢出（我不造）

我猜在push里面，IsFull的判断，如果满了，就发出溢出声明