堆排序（heapsort)

    #include <iostream>
    using namespace std;
    void swap(int arr[], int i, int j) 
    {
    	int temp = arr[i];
    	arr[i] = arr[j];
    	arr[j] = temp;
    }
    void heapify(int tree[], int n, int i)
    {
    	if (i >= n) { return; }
    	int c1 = 2 * i + 1;
    	int c2 = 2 * i + 2;
    	int max = i;
    	if (c1<n&&tree[c1]>tree[max]) {
    		max = c1;
    	}
    	if (c2<n&&tree[c2]>tree[max]) {
    		max = c2;
    	}
    	if (max != i) {
    		swap(tree, max, i);
    		heapify(tree,n, max);
    	}
    }
    void build_heap(int tree[],int n)
    {
    	int last_node=n-1;
    	int parent=(last_node-1)/2;
    	int i;
    	for(i=parent;i>=0;i--)
    	{
    		heapify(tree,n,i);
    	}
    }
    void heap_sort(int tree[], int n)
    {
    	build_heap(tree,n);
    	int i;
    	for(i=n-1;i>=0;i--)
    	{
    		swap(tree,i,0);
    		heapify(tree,i,0);
    	}
    }
    int main()
    {
    	int tree[] = { 10,4,3,5,1,2 };
    	int n = 6;
    	heap_sort(tree,n);
    	int i;
    	//heapify(tree, n, 0);
    	for (i = 0;i < n;i++)
    	{
    		printf("%d
", tree[i]);
    	}
    	return 0;
    }