我的“归并算法”实现

这是我的“归并算法”Java实现！

/*
 * 练习：归并算法
 * 功能：对一堆数据进行排序
 * 作者：陈沛锐
 * 时间：2013.03.25
 */
package part01.chapter02;

import java.util.Random;
import java.util.Scanner;

public class _3exercise {
    public static void main(String[] args) {
        // int[] A={1,3,5,7,9,10,2,4,6,8,10};
        // MERGE myMerge = new MERGE(A, 0, 5, 10);
        //create data
        System.out.println("Please inter the data counts");
        Scanner scanner=new Scanner(System.in);
        int leng = scanner.nextInt();
        CreateDate createDate = new CreateDate(leng);
        int[] A = createDate.create();
        //sort data by MERGE_SORT()
        MERGE_SORT merge_sort=new MERGE_SORT();
        merge_sort.sort(A,0,leng-1);
        //output sorted data
        System.out.println("the sorted data are follow:");
        for(int i=0;i<leng;i++){
            System.out.print(A[i]+" ");
        }
    }


}
//MERGE_SORT
class MERGE_SORT{
        public void sort(int[] A, int p, int r) {
        MERGE merge = new MERGE();
        int q = 0;
        if (p < r) {
            q = (p + r) / 2;
            sort(A, p, q);
            sort(A, q+1, r);
            merge.sort(A, p, q, r);
        }
    }
}
// Create date
class CreateDate {
    int leng = 0;
    Random randomInt = new Random();
    CreateDate(int leng) {
        this.leng = leng;
    }

    public int[] create() {
        int[] A = new int[leng];
        System.out.println("Please inter the max number(<10000):");
        Scanner scanner=new Scanner(System.in);
        int maxNum = scanner.nextInt();
        if(maxNum>10000){
            System.out.println("enter error!");
            System.exit(0);
        }
        for (int i = 0; i < leng; i++) {
            A[i] = randomInt.nextInt(maxNum);
        }
        return A;
    }
}

// MERGE class for merger data
class MERGE {
    int[] L = null;
    int[] R = null;

    // sort
    public void sort(int[] A, int p, int q, int r) {
        L = new int[q - p + 2];
        R = new int[r - q + 1];
        for (int i = 0; i < q - p + 1; i++) {
            L[i] = A[p + i];
        }
        L[q - p + 1] = 10000;// 10000 is max number
        for (int j = 0; j < r - q; j++) {
            R[j] = A[q + 1 + j];
        }
        R[r - q] = 10000;// 10000 is max number
        // test output A[p..r]
        // for(int i=p;i<r+1;i++){
        // System.out.print(A[i]+" ");
        // }
        int j = 0;
        int k = 0;
        for (int i = 0; i < r - p + 1; i++) {
            if (L[j] <= R[k]) {
                A[p + i] = L[j];
                j++;
            } else {
                A[p + i] = R[k];
                k++;
            }
        }
    }
}