【数据结构】二叉树-堆（函数实现）

#pragma once
#include<stdio.h>
#include<stdlib.h>
#include<assert.h>
#include<stdbool.h>
typedef int HPDataType;
typedef struct Heap
{
  HPDataType* a;
  int size;
  int capacity;
}HP;
//初始化
void HeapInit(HP* php);
//销毁
void HeapDestroy(HP* php);
//堆插入
void HeapPush(HP* php, HPDataType x);
//规定删除堆顶（根节点）
void HeapPop(HP* php);
//找堆顶元素
HPDataType HeapTop(HP* php);
//堆的元素个数
size_t HeapSize(HP* php);
//是否是空
bool HeapEmpty(HP* php);
//向上调整
void AdjustUp(HPDataType* a, int child);
//向下调整
void AdjustDown(HPDataType* a, int size, int parent);

void HeapInit(HP* php)
{
  assert(php);
  php->a = NULL;
  php->capacity = 0;
  php->size = 0;
}

void HeapDestroy(HP* php)
{
  assert(php);
  free(php->a);
  php->a = NULL;
  php->capacity = php->size = 0;
}

//O(log N)
void HeapPush(HP* php, HPDataType x)
{
  assert(php);
  if (php->size == php->capacity)
  {
  int newCapacity = php->capacity == 0 ? 4 : php->capacity * 2;
  HPDataType* tmp = (HPDataType*)realloc(php->a, newCapacity * sizeof(HPDataType));
  if (tmp == NULL)
  {
    perror("realloc fail");
    exit(-1);
  }
  php->a = tmp;
  php->capacity = newCapacity; 
  }
  php->a[php->size] = x;
  php->size++;
  AdjustUp(php->a, php->size - 1);
}

//小堆
void AdjustUp(HPDataType* a, int child)
{
  int parent = (child - 1) / 2;
  while (child>0)
  {
  if (a[child] < a[parent])
  {
    Swap(&a[child], &a[parent]);
    child = parent;
    parent = (parent - 1) / 2;
  }
  else
  {
    break;
  }
  }
}

void Swap(HPDataType* p1, HPDataType* p2)
{
  HPDataType tmp = *p1;
  *p1 = *p2;
  *p2 = tmp;
}

//小堆
void AdjustDown(HPDataType* a, int size, int parent)
{
  int child = parent * 2 + 1; 
  while (child<size)
  {
  //假设左孩子小，如果假设错了，就更新一下
  if (child+1<size&&a[child + 1] < a[child])
  {
    child++;
  }
  if (a[child] < a[parent])
  {
    Swap(&a[child], &a[parent]);
    parent = child;
    child = parent * 2 + 1;
  }
  else
  {
    break;
  }
  }
}

void HeapPop(HP* php)
{
  assert(php);
  assert(php->size>0);
  Swap(&php->a[0], &php->a[php->size - 1]);
  php->size--;
  AdjustDown(php->a,php->size,0);
}

HPDataType HeapTop(HP* php)
{
  assert(php);
  assert(php->size>0);
  return php->a[0];
}

size_t HeapSize(HP* php)
{
  assert(php);
  return php->size;
}

bool HeapEmpty(HP* php)
{
  assert(php);
  return php->size == 0;
}