两个队列实现栈

实现：

/**********************************
两个队列实现栈
by Rowandjj
2014/7/21
**********************************/
#include<iostream>
using namespace std;
typedef struct _NODE_
{
	int data;
	struct _NODE_ *next;
}Node,*pNode;
typedef struct _QUEUE_
{
	pNode pHead;
	pNode pTail;
	int size;
}Queue,*pQueue;
typedef struct _STACK_
{
	Queue q1;
	Queue q2;
}Stack,*pStack;
void InitQueue(pQueue pq)
{
	pq->pHead = pq->pTail = (pNode)malloc(sizeof(Node));
	if(!pq->pHead)
	{
		exit(-1);
	}
	pq->pHead->next = NULL;
	pq->size = 0;
}
void Enqueue(pQueue pq,int data)
{
	if(pq == NULL)
	{
		return;
	}
	pNode pNew = (pNode)malloc(sizeof(Node));
	if(!pNew)
	{
		exit(-1);
	}
	pNew->data = data;
	pNew->next = NULL;
	pq->pTail->next = pNew;
	pq->pTail = pNew;
	pq->size++;
}
void Dequeue(pQueue pq,int* data)
{
	if(pq == NULL)
	{
		*data = -1;
		return;
	}
	pNode pDel = pq->pHead->next;
	if(pDel != NULL)
	{
		*data = pDel->data;
		pq->pHead->next = pDel->next;
		if(pq->pTail == pDel)
		{
			pq->pTail = pq->pHead;
		}
		free(pDel);
		pq->size--;
	}
	else
	{
		*data = -1;
		return;
	}
}
int QueueSize(Queue q)
{
	return q.size;
}
void DestroyQueue(pQueue pq)
{
	int data;
	if(pq == NULL)
	{
		return;
	}
	while(pq->size > 0)
	{
		Dequeue(pq,&data);
	}
	free(pq->pHead);
}
void InitStack(pStack ps)
{
	InitQueue(&ps->q1);
	InitQueue(&ps->q2);
}
void Push(pStack ps,int data)
{
	if(QueueSize(ps->q2) == 0)
	{
		Enqueue(&ps->q1,data);	
	}
	else
	{
		Enqueue(&ps->q2,data);
	}
}
int Pop(pStack ps)
{
	int data;
	if(QueueSize(ps->q1)==0 && QueueSize(ps->q2)==0)
	{
		return -1;
	}
	if(QueueSize(ps->q1) != 0)
	{
		while(QueueSize(ps->q1) != 1)
		{
			Dequeue(&ps->q1,&data);
			Enqueue(&ps->q2,data);
		}
		Dequeue(&ps->q1,&data);
		return data;
	}
	if(QueueSize(ps->q2) != 0)
	{
		while(QueueSize(ps->q2) != 1)
		{
			Dequeue(&ps->q2,&data);
			Enqueue(&ps->q1,data);
		}
		Dequeue(&ps->q2,&data);
		return data;
	}
	return -1;
}
void DestroyStack(pStack ps)
{
	if(ps == NULL)
	{
		return;
	}
	DestroyQueue(&ps->q1);
	DestroyQueue(&ps->q2);
}
int main()
{
	int i,data;
	Stack s;
	InitStack(&s);
	for(i = 0; i < 4; i++)
	{
		cin>>data;
		Push(&s,data);
	}
	for(i = 0; i < 5; i++)
	{
		cout<<Pop(&s)<<endl;
	}
	DestroyStack(&s);
	return 0;
}

两个队列实现栈,布布扣,bubuko.com

两个队列实现栈

原文：http://blog.csdn.net/chdjj/article/details/38015287