HeapSort

在O(nlgn)的复杂度下可以实现排序，

# include <stdio.h>
# define HEAP_SIZE    7

int Heap_Size = HEAP_SIZE - 1 ;
int Parent(int i){

return i/2;
}

int Left(int i){

return 2*i;
}

int Right(int i ){

return 2*i+1;
}

void Exchange(int *p , int * q){
int temp = * p ;
*p = * q;
*q = temp ;
}

void Max_Heapfy(int A[], int i){
int left = Left(i);
int right= Right(i);
int maxer ;

if( left <= Heap_Size && A[i] < A[left]){
maxer = left;
}else{
maxer = i;
}
if (right <= Heap_Size &&  A[maxer] < A[right] ){
maxer = right;
}

if (i != maxer){
Exchange(&A[maxer],&A[i]);
Max_Heapfy(A,maxer);
}

return ;
}

void Build_Max_Heap(int A[]){
for (int i = Heap_Size/2 ; i >= 0 ; i --){
Max_Heapfy(A,i);
}
}

void HeapSort(int A[]){
Build_Max_Heap(A);
for (int i = Heap_Size ; i >= 1 ;i --){
Exchange(&A[0],&A[i]);
Heap_Size = Heap_Size - 1;
Max_Heapfy(A,0);
}
}

int main(void){
int a[] = { 7,1,3,2,4,6,5};
HeapSort(a);
for (int i = 0 ; i < HEAP_SIZE ; i ++ ){
printf("%5d  ", a[i]);
}

return 0;
}