LeetCode | 232. 用栈实现队列

#include<stdio.h>
#include<stdlib.h>
#include<stdbool.h>
#include<assert.h>
typedef int STDataType;
typedef struct Stack
{
  STDataType* a;
  int capacity;
  int top;
}ST;
void StackInit(ST* ps);
// 入栈
void StackPush(ST* ps, STDataType x);
// 出栈
void StackPop(ST* ps);
// 获取栈顶元素
STDataType StackTop(ST* ps);
// 获取栈中有效元素个数
int StackSize(ST* ps);
// 检测栈是否为空，如果为空返回非零结果，如果不为空返回0
bool StackEmpty(ST* ps);
// 销毁栈
void StackDestroy(ST* ps);
void StackInit(ST* ps)
{
  assert(ps);
  ps->a = NULL;
  ps->capacity = ps->top = 0;
}
void StackPush(ST* ps, STDataType x)
{
  assert(ps);
  if (ps->capacity == ps->top)
  {
    STDataType newcapacity = ps->capacity == 0 ? 4 : ps->capacity * 2;
    STDataType* tmp = (STDataType*)realloc(ps->a, sizeof(STDataType) * newcapacity);
    if (tmp == NULL)
    {
      perror("realloc fail!\n");
      return;
    }
    ps->capacity = newcapacity;
    ps->a = tmp;
  }
  ps->a[ps->top] = x;
  ps->top++;
}
// 出栈
void StackPop(ST* ps)
{
  assert(ps);
  assert(ps->top > 0);
  ps->top--;
}
// 获取栈顶元素
STDataType StackTop(ST* ps)
{
  assert(ps);
  assert(ps->top > 0);
  return ps->a[ps->top - 1];
}
// 获取栈中有效元素个数
int StackSize(ST* ps)
{
  assert(ps);
  return ps->top;
}
// 检测栈是否为空，如果为空返回非零结果，如果不为空返回0
bool StackEmpty(ST* ps)
{
  assert(ps);
  return ps->top == 0;
}
// 销毁栈
void StackDestroy(ST* ps)
{
  assert(ps);
  ps->a = NULL;
  ps->capacity = ps->top = 0;
}
typedef struct {
    ST pushst;
    ST popst;
} MyQueue;
MyQueue* myQueueCreate() {
    MyQueue* obj = (MyQueue*)malloc(sizeof(MyQueue));
    StackInit(&obj->pushst);
    StackInit(&obj->popst);
    return obj;
}
void myQueuePush(MyQueue* obj, int x) {
    StackPush(&obj->pushst,x);
}
int myQueuePeek(MyQueue* obj) {
    if(!StackEmpty(&obj->popst))
    {
        return StackTop(&obj->popst);
    }
    else
    {
        while(!StackEmpty(&obj->pushst))
        {
            StackPush(&obj->popst,StackTop(&obj->pushst));
            StackPop(&obj->pushst);
        }
        return StackTop(&obj->popst);
    }
}
int myQueuePop(MyQueue* obj) {
    int front = myQueuePeek(obj);
    StackPop(&obj->popst);
    return front;
}
bool myQueueEmpty(MyQueue* obj) {
    return StackEmpty(&obj->pushst) && StackEmpty(&obj->popst);
}
void myQueueFree(MyQueue* obj) {
    StackDestroy(&obj->popst);
    StackDestroy(&obj->pushst);
    free(obj);
}