堆排序 经典代码

最近学习一下堆排序，自己在理解了思想后尝试写了一下，开始还觉得写的不错，但后来看了大牛的代码，顿时觉得自己的代码丑陋的没法再说了。所以按照大牛的代码写了一下，参考http://blog.kingsamchen.com/archives/547#viewSource，个人对他上面的代码稍微缩减了一点，觉得更美了一点点。。。。

最大堆，从小到大排序代码：

#include <iostream>#define lson(key) ((key << 1) + 1)#define rson(key) ((key + 1) << 1)#define perent(key) ((key - 1) >> 1)// #define perent(key) (((key + 1) >> 1) - 1)using namespace std;void MaxHeapify(int tree[], int key, int length){//保持最大堆的性质,三个参数，数组，检查的起始下标和堆大小int left = lson(key), right = rson(key), flag = key;if(left <= length && tree[flag] < tree[left])flag = left;if(right <= length && tree[flag] < tree[right])flag = right;if(flag != key){swap(tree[key], tree[flag]);MaxHeapify(tree, flag, length);}}void BuildMaxHeap(int tree[], int length){//把原数组调整成最大堆for(int i = perent(length); i >= 0 ; --i)MaxHeapify(tree, i, length);}void HeapSort(int tree[], int length){//堆排序主函数BuildMaxHeap(tree, length - 1);for(int i = length - 1; i > 0; --i){swap(tree[0], tree[i]);MaxHeapify(tree, 0, i - 1);}}int main(){int tree[10] = {9,12,17,30,50,20,60,65,4,49};HeapSort(tree, 10);for(int i = 0;i < 10; i ++)cout << tree[i] << " ";cout << endl;}