C语言实现大顶堆的示例代码

typedef int Heaptype;
 
typedef struct Heap
{
    Heaptype* head;   
    int size;         //记录堆总容量 
    int capacity;     //记录当前数据总个数
}Heap;
 
//堆的初始化
void Heap_Init(Heap* pphead)
{
    assert(pphead);
    pphead->head = NULL;
    pphead->size = 0;
    pphead->capacity = 0;
}

//向上调整
void adjust_up(Heap* pphead)
{
    int child = pphead->capacity;
    int parent = (child - 1) / 2;
    for (; pphead->head[parent] < pphead->head[child];)//判断是否符合大顶堆
    {
        swap(&(pphead->head[parent]),&(pphead->head[child]));//进行交换
        child = parent;
        parent = (child - 1) / 2;
    }
}
 
//插入数据
void Heap_push(Heap* pphead, Heaptype data)
{
    assert(pphead);
    //判断是否满容量并扩容
    Heap_realloc(pphead);
    pphead->head[pphead->capacity] = data;
    //向上调整
    adjust_up(pphead);
    pphead->capacity++;
}

//删除数据
void Heap_pop(Heap* pphead)
{
    assert(pphead);
    assert(pphead->capacity > 0);      //防止堆为空
    //将顶部数据与尾部数据交换
    swap(&(pphead->head[0]),&( pphead->head[pphead->capacity-1]));
    pphead->capacity--;
    //向下调整
    adjust_down(pphead,0);
}
 
//向下调整
void Adjust_down(int* a, int size, int parent)
{
    assert(a);
    for (int child = parent * 2 + 1; child <= size; child = parent * 2 + 1)
    {
        //默认用左孩纸与母节点比较，如果右孩纸比左孩纸大且不越界则交换
        if (a[child] > a[child + 1] && child + 1 <= size)
            child = child + 1;
        //比较孩纸和母节点
        if (a[child] < a[parent])
        {
            int temp = a[child];
            a[child] = a[parent];
            a[parent] = temp;
        }
        //向下继续比较
        parent = child;
    }
}

//判断是否扩容
void Heap_realloc(Heap* pphead)
{
    assert(pphead);
    if (pphead->size == pphead->capacity)
    {
        Heaptype Newsize = (pphead->size == 0) ? 4 : (pphead->size * 2);
        Heaptype* Newhead = (Heaptype*)realloc(pphead->head,sizeof(Heaptype) * Newsize);
        if (Newhead == NULL)
        {
            perror("realloc");
            exit(-1);
        }
        pphead->head = Newhead;
        pphead->size = Newsize;
    }
}
 
//判断堆是否为空
bool Heap_Empty(Heap* pphead)
{
    if (pphead->capacity)
        return false;
    return true;
}
//取对顶数据
Heaptype Heap_top(Heap* pphead)
{
    return pphead->head[0];
}
//销毁堆
void Heap_Destory(Heap* pphead)
{
    assert(pphead);
    free(pphead->head);
    pphead->head = NULL;
    pphead->size = 0;
    pphead->capacity = 0;
}