算法思想见算法导论，这里是我的具体C++实现，代码可直接编译运行。
#include <iostream>
using namespace std;
void heapfy(int a[], int start, int end) {
int large = start;
int i = start;
int swap_tmp = 0;
while (i < end) {
if (2*i+1 < end) {
if (a[2*i+1] > a[large]) {
large = 2*i+1;
}
}
if (2*i+2 < end) {
if (a[2*i+2] > a[large]) {
large = 2*i+2;
}
}
if (i != large) {
swap_tmp = a[i];
a[i] = a[large];
a[large] = swap_tmp;
i = large;
} else {
break;
}
}
}
void print (int a[], int len) {
for (int i = 0; i < len; i++) {
cout << a[i] << " ";
}
cout << endl;
}
void build_heap(int a[], int len) {
int mid = len/2 - 1;
for (int i=mid; i>=0; i--) {
heapfy(a, i, len);
cout << i << ":";
print(a, len);
}
}
void heap_sort (int a[], int len) {
build_heap(a, len);
int swap_tmp = 0;
for (int i=len-1; i>=1; i--) {
swap_tmp = a[0];
a[0] = a[i];
a[i] = swap_tmp;
heapfy(a, 0, i);
}
}
int main () {
int a[] = {0, 9,2,13,4,5,20,11,7};
int array_size = sizeof(a)/sizeof(int);
//cout << array_size << endl;
//heapfy(a, 0, array_size);
heap_sort(a, array_size);
print(a, array_size);
return 0;
}
