堆排序（java实现）

public class Test04 {

    static int a[] = {9,8,7,6,5,4,3,2,1,11,12,10,19,18,17,16};
    public static void main(String[] args) {
        init();
        int i,k;
        for(i = 0;i< a.length -1;i++){
            k = a[0];
            a[0] = a[a.length-1-i];
            a[a.length-1-i] = k;
            sort(0,a.length-i-1);
        }
        for(int b :a){
            System.out.print(b+" ");
        }
    }
    
    public static void init(){
        int i = (a.length-1)/2;
        for(;i >=0;i--){
            sort(i,a.length);
        }
    }
    
    public static void sort(int i,int length){
        int k = i;
        if(2*i+1 < length && a[k] < a[2*i+1]){
            k = 2*i+1;
        }
        if(2*i+2 < length && a[k] < a[2*i+2] ){
            k = 2*i+2;
        }
        if(k != i){
            a[i] = a[k]+a[i];
            a[k] = a[i]-a[k];
            a[i] = a[i]-a[k];
            sort(k,length);
        }
    }

}