算法导论：堆排序（java实现）

import java.util.*;
public class Sort {
	public static void main(String[] args) {
		int[] a;
		a = setArray();
		heapsort(a);
		for(int e:a)
			System.out.print(e+" ");
	}
	public static int[] setArray() {
		int n;
		Scanner in = new Scanner(System.in);
		n = in.nextInt();
		int[] a = new int[n];
		for(int i=0;i<a.length;i++) {
			a[i] = in.nextInt();
		}
		return a;
	}
	public static int parent(int i) {
		return i/2;
	}
	public static int left(int i) {
		return 2*i;
	}
	public static int right(int i) {
		return 2*i+1;
	}
	public static void max_heapify(int[] a,int i,int b) {
		int l,r,largest;
		l = left(i);
		r = right(i);
		if(l<=b&&a[l-1]>a[i-1])
			largest = l;
		else
			largest = i;
		if(r<=b&&a[r-1]>a[largest-1])
			largest = r;
		if(largest!=i) {
			int temp;
			temp = a[i-1];
			a[i-1] = a[largest-1];
			a[largest-1] = temp;
			max_heapify(a,largest,b);
		}
	}
	public static void build_max_heap(int[] a) {
		int heap,j;
		heap = a.length/2;
		for(j=heap;j>=1;j--) {
			max_heapify(a,j,a.length);
		}
	}
	public static void heapsort(int[] a) {
		int heap,temp;
		heap = a.length;
		build_max_heap(a);
		for(int i=heap;i>=2;i--) {
			temp = a[i-1];
			a[i-1] = a[0];
			a[0] = temp; 
			heap--;
			max_heapify(a,1,heap);
		}
	}
}