算法导论&堆排序&堆实现的优先队列

#include<iostream>
using namespace std;
#define parent(i) (i/2)
#define left(i) (i*2)
#define right(i) (i*2+1)
#define len(a)  sizeof(a)/sizeof(a[0])
#define INF 0x3f3f3f
const int maxn = 100;
int heap_size;
int length;
int A[maxn];

//堆排序
void max_heapify(int A[],int i);//维护一个最大堆
void build_max_heap(int A[]);   //建立堆
void heapsort(int A[]); //排序

//优先队列
void heap_maximum(int A[]); //返回最大关键字元素
int heap_extract_max(int A[]);  //返回最大关键字元素并从对队列中删除
void heap_increase_key(int A[],int i,int key);  //把某节点值增加到key
void max_heap_insert(int A[],int key);  //把key值插入到队列中

int main(){
int a[] = {110,4,34,55,66,32,22};
length = len(a);
heapsort(a);
for(int i=0;i<length;i++){
cout<<a[i]<<" ";
}
}

void max_heapify(int A[],int i){
int largest;
int l = left(i);
int r = right(i);
if(l<=heap_size&&A[l]>A[i]){
largest = l;
}else{
largest = i;
}

if(r<=heap_size&&A[r]>A[largest])
largest = r;

if(largest!=i){
int t = A[i];
A[i] = A[largest];
A[largest] = t;
max_heapify(A,largest);
}

}

void build_max_heap(int A[]){
heap_size = length;
for(int i=length/2;i>=0;i--){
max_heapify(A,i);
}
}

void heapsort(int A[]){
build_max_heap(A);
for(int i=length;i>0;i--){
int t = A[0];
A[0] = A[i];
A[i] = t;

heap_size--;
max_heapify(A,0);
}
}

void heap_maximum(int A[]){
return A[0];
}

int heap_extract_max(int A[]){
if(heap_size<0) return -1;
max = A[0];
A[0] = A[heap_size];
heap_size--;
max_heapify(A,0);
return max;
}

int heap_increase_key(int A[],int i,int key){
if(key<A[i])    return -1;
A[i] = key;
while(i>0&&A[parent(i)]<A[i]){
int t = A[i];
A[i] = A[parent(i)];
A[parent(i)] = t;
i = parent(i);
}
}

void max_heap_insert(int A[],int key){
heap_size++;
A[heap_size] = -INF;
heap_increase_key(heap_increase_key(A,heap_size,key));
}