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