数据结构-*-归并排序

package per.lihao.sort.complexsort;

import per.lihao.sort.SortSequence;
import per.lihao.sort.simplesort.BubbleSort;

/**
 * 二路归并排序
 * 时间复杂度为：O(nlogn)
 * Author: LiHao
 * Time: 2018/12/13 14:13
 */
public class MergeSort {
    private static void mergeSort(int[] array,int begin,int end){
        if (begin>=end)
        {
            return;
        }
        int mid = (begin+end) >> 1;
        mergeSort(array,begin,mid);
        mergeSort(array,mid+1,end);
        merge(array,begin,mid,end);
    }
    private static void merge(int[] array,int begin,int mid,int end){
        int[] a = new int[end-begin+1];
        int i=begin,j=mid+1,k=0;
        while (i<mid+1 && j<end+1){
            if (array[i]<array[j]){
                a[k++] = array[i++];
            }else {
                a[k++] = array[j++];
            }
        }
        if (i<=mid){
            for (int start = i;start<=mid;start++){
                a[k++] = array[start];
            }
        }
        if (j<=end){
            for (int start = j;start<=end;start++){
                a[k++] = array[start];
            }
        }
        k = 0;
        for (int start = begin;start<=end;start++){
            array[start] = a[k++];
        }
    }
    public static int[] sort(int[] array,boolean reverse){
        int[] result = array.clone();
        mergeSort(result,0,result.length-1);
        return result;
    }

    public static void main(String[] args) {
        SortSequence ss = new SortSequence(82,195,19,108,153,39,120,125,136,181);
        ss.printMem();
        System.out.println("****************************");
        int[] a = MergeSort.sort(ss.getMem(),true);
        BubbleSort.printArray(a);
    }
}