leetcode225.用队列实现栈

typedef int QDataType;
typedef struct QueueNode
{
  struct QueueNode* next;
  QDataType data;
}QueueNode;
typedef struct Queue
{
  QueueNode* phead;
  QueueNode* ptail;
}Queue;
bool QueueEmpty(Queue* pq)
{
  assert(pq);
  return pq->ptail == NULL && pq->phead == NULL;
}
void QueueInit(Queue* pq)
{
  assert(pq);
  pq->phead = pq->ptail = NULL;
}
void QueueDestory(Queue* pq)
{
  assert(pq);
  QueueNode* cur = pq->phead;
  while (cur)
  {
    QueueNode* next = cur->next;
    free(cur);
    cur = next;
  }
  pq->phead = pq->ptail = NULL;
}
void QueuePush(Queue* pq, QDataType x)
{
  assert(pq);
  QueueNode* newnode = (QueueNode*)malloc(sizeof(QueueNode));
  if (newnode == NULL)
  {
    printf("malloc fail\n");
    exit(-1);
  }
  newnode->data = x;
  newnode->next = NULL;
  if (pq->ptail == NULL)
  {
    pq->phead = pq->ptail = newnode;
  }
  else
  {
    pq->ptail->next = newnode;
    pq->ptail = newnode;
  }
}
void QueuePop(Queue* pq)
{
  assert(pq);
  if (pq->phead->next == NULL)
  {
    free(pq->phead);
    pq->phead = pq->ptail = NULL;
  }
  else
  {
    QueueNode* next = pq->phead->next;
    free(pq->phead);
    pq->phead = next;
  }
}
int QueueSize(Queue* pq)
{
  assert(pq);
  int n = 0;
  QueueNode* cur = pq->phead;
  while (cur)
  {
    n++;
    cur = cur->next;
  }
  return n;
}
QDataType QueueFront(Queue* pq)
{
  assert(pq);
  assert(!QueueEmpty(pq));
  return pq->phead->data;
}
QDataType QueueBack(Queue* pq)
{
  assert(pq);
  assert(!QueueEmpty(pq));
  return pq->ptail->data;
}
typedef struct {
  Queue q1;
  Queue q2;
} MyStack;
MyStack* myStackCreate() {
    MyStack* pst=(MyStack*)malloc(sizeof(MyStack));
    QueueInit(&pst->q1);
    QueueInit(&pst->q2);
    return pst;
}
void myStackPush(MyStack* obj, int x) {
    assert(obj);
    if(!QueueEmpty(&obj->q1))
    {
       QueuePush(&obj->q1,x);
    }
    else
    {
       QueuePush(&obj->q2,x);
    }
}
int myStackPop(MyStack* obj) {
    assert(obj);
    Queue * emptyq=&obj->q1;
    Queue * noemptyq=&obj->q2;
    if(!QueueEmpty(&obj->q1))
    {
        emptyq=&obj->q2;
        noemptyq=&obj->q1;
    }
    //将非空队列中的size-1个导入空队列
    while(QueueSize(noemptyq)>1)
    {
        QueuePush(emptyq,QueueFront(noemptyq));
        QueuePop(noemptyq);//去除
    }
    int top=QueueFront(noemptyq);
      QueuePop(noemptyq);
      return top;
}
int myStackTop(MyStack* obj) {
   if(!QueueEmpty(&obj->q1))
   {
       return QueueBack(&obj->q1);
   }
   else
   {
       return QueueBack(&obj->q2);
   }
}
bool myStackEmpty(MyStack* obj) {
    assert(obj);
return   QueueEmpty(&obj->q1)&&QueueEmpty(&obj->q2);
}
void myStackFree(MyStack* obj) {
    assert(obj);
    QueueDestory(&obj->q1);
    QueueDestory(&obj->q2);
    free(obj);
}