堆排序 （包括升序和降序，Arraylist 实现）

补充上一篇
利用Arraylist实现的堆排序(包含升序和降序)

import java.util.ArrayList;import java.util.Random;//采用Arraylist实现堆排序public class Main {    //为了方便 采用索引从 1 开始    private static int N = 10;// 数组的大小    static Random rand = new Random();    public static void main(String[] args) {        // TODO Auto-generated method stub        test_HeapSort_DES();        test_HeapSort_ASC();    }    private static void test_HeapSort_DES() {        // TODO Auto-generated method stub        ArrayList<Integer> arrayList=new ArrayList<>();        arrayList.add(-1);        for (int i = 1; i <= N; i++) {            arrayList.add(rand.nextInt(1000));        }        System.out.println("排序前：");        print(arrayList);               System.out.println("排序后(降序)：");        print(HeapSort_DES(arrayList));    }    private static void test_HeapSort_ASC() {        // TODO Auto-generated method stub        ArrayList<Integer> arrayList=new ArrayList<>();        arrayList.add(-1);        for (int i = 1; i <= N; i++) {            arrayList.add(rand.nextInt(1000));        }        System.out.println("排序前：");        print(arrayList);               System.out.println("排序后(升序)：");        print(HeapSort_ASC(arrayList));    }    private static ArrayList<Integer> HeapSort_ASC(ArrayList<Integer> arrayList) {        // TODO Auto-generated method stub        Build_Max_Heap(arrayList);        ArrayList<Integer> temp=new ArrayList<>();        temp.add(-1);//方便打印        while(arrayList.size()>1){            temp.add(1,arrayList.get(1));//与逆序的差别 每次插在第一个            arrayList.remove(1);            Max_Heapfy(arrayList,1);        }        return temp;    }    private static ArrayList<Integer> HeapSort_DES(ArrayList<Integer> arrayList) {        // TODO Auto-generated method stub        Build_Max_Heap(arrayList);        ArrayList<Integer> temp=new ArrayList<>();        temp.add(-1);//方便打印        while(arrayList.size()>1){            temp.add(arrayList.get(1));            arrayList.remove(1);            Max_Heapfy(arrayList,1);        }        return temp;    }    private static void Build_Max_Heap(ArrayList<Integer> arrayList) {        // TODO Auto-generated method stub        int length=arrayList.size()-1;        for(int i=length/2;i>0;i--){            Max_Heapfy(arrayList, i);        }    }    private static void Max_Heapfy(ArrayList<Integer> arrayList, int i) {        // TODO Auto-generated method stub        if(arrayList.size()<=1)            return;        int l=left(i);        int r=right(i);        int largest=0;        if(l<arrayList.size() && arrayList.get(l)>arrayList.get(i)){            largest=l;        }else{            largest=i;        }        if(r<arrayList.size() && arrayList.get(r)> arrayList.get(largest)){            largest=r;        }        if(largest!=i){            int temp =  arrayList.get(i);            arrayList.set(i, arrayList.get(largest));            arrayList.set(largest, temp);                   Max_Heapfy(arrayList,largest);        }           }    private static int right(int i) {        // TODO Auto-generated method stub        return 2*i+1;    }    private static int left(int i) {        // TODO Auto-generated method stub        return 2*i;    }    //打印    private static void print(ArrayList<Integer> arrayList) {        // TODO Auto-generated method stub        for(int i=1;i<arrayList.size();i++){            System.out.print(arrayList.get(i)+"\t");        }        System.out.println();    }}

结果截图