优先队列二叉堆 C语言实现

#ifndef _BinHeap_H

struct Heapstruct;
typedef struct Heapstruct *PriorityQueue;
PriorityQueue Initialize(int MaxElements);
void Destroy(PriorityQueue h);
void MakeEmpty(PriorityQueue h);
void Insert(int x,PriorityQueue h);
int DeleteMin(PriorityQueue h);
int FindMin(PriorityQueue h);
int IsEmpty(PriorityQueue h);
int IsFull(PriorityQueue h);
void DecreaseKey(int position,int change,struct Binaryheap h);

void IncreaseKey(int position,int change,struct Binaryheap h);
#endif

#define MinData -1

struct Heapstruct{
	int capacity;
	int size;
	int *a;
};

PriorityQueue Initialize(int MaxElements){
	PriorityQueue h;
	h = (PriorityQueue)malloc(sizeof(struct Heapstruct));
	if(h == NULL){
		printf("Out of Space\n");
		return NULL;
	}
	h->a = (int *)malloc(sizeof(int)*MaxElements);
	if(h->a == NULL){
		printf("Out of Space\n");
		return NULL;
	}
	h->capacity = MaxElements;
	h->size = 0;
	h->a[0] = MinData;
	return h;
}

int IsEmpty(PriorityQueue h){
	return h->size == 0;
}

int IsFULL(PriorityQueue h){
	return h->size == h->capacity-1;
}

void Insert(int x,PriorityQueue h){
	int i;
	if(IsFULL(h)){
		printf("Priority queue is full\n");
		return ;
	}
	for(i = ++h->size;h->a[i/2]>x;i = i/2)
		h->a[i] = h->a[i/2];
	h->a[i] = x;
}

int DeleteMin(PriorityQueue h){
	int min,last,child,i;
	if(IsEmpty(h)){
		printf("Priority queue is empty\n");
		return -1;
	}
	min = h->a[1];
	last = h->a[h->size--];
	for(i = 1;2*i<=h->size;i = child){
		child = 2*i;
		if(child!=h->size&&h->a[child]>h->a[child+1])
			child++;
		if(h->a[child]last)
			h[i] = h->a[child];
		else break;
	}
	h[i] = last;
	return min;
}

void MakeEmpty(PriorityQueue h){
	h->size = 0;
}

int FindMin(PriorityQueue h){
	if(IsEmpty(h)){
		printf("Priority queue is empty\n");
		return -1;
	}
	return h->a[1];
}

void Destroy(PriorityQueue h){
	free(h->a);
	free(h);
}

void DecreaseKey(int position,int change,struct Binaryheap h){
	int child,x;
	if(h->sizea[position] += change;
	x = h->a[position];
	for(i=position;2*i<=h->size;i = child){
		child = 2*i;
		if(child!=h->size&&h->a[child]>h->a[child + 1])
			child++;
		if(h->a[child]a[i] = h->a[child];
		else break;
	}
	h->a[i] = x;
}

void IncreaseKey(int position,int change,struct Binaryheap h){
	if(h->sizea[position] - change;
	for(i = position;h->a[i/2]>x;i = i/2;)
		h->a[i] = h->a[i/2];
	h->a[i] = x;
}