MergeSort, Java - rextester

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//Title of this code
//'main' method must be in a class 'Rextester'.
//Compiler version 1.7.0_51

import java.util.*;
import java.lang.*;

class Rextester
{  
    public static void main(String args[])
    {
        int[] data={1, 2,5,7, 8, 3, 10};
        int[] res=mergeSort(data, 0, data.length-1);
        for (int i=0;i<data.length;i++)
        {
            System.out.println(res[i]);
        }
        return;
    }
    private static int[] mergeSort(int[] data, int start, int end)
    {
        if (data==null||data.length==0)
            return data;
        int[] res=new int[end-start+1];
        if (start==end)
        {
            res[0]=data[start];
            return res;
        }
        //divide
        int mid=(start+end)/2;
        int[] data1=mergeSort(data, start, mid);
        int[] data2=mergeSort(data, mid+1, end);
        //merge
        int cur1=0;
        int cur2=0;
        int curn=0;
        while (cur1<=data1.length-1&&cur2<=data2.length-1)
        {
            if (data1[cur1]<=data2[cur2])
            {
                res[curn]=data1[cur1];
                cur1++;
            }
            else
            {
                res[curn]=data2[cur2];
                cur2++;
            }
            curn++;   
        }
        if (cur1==data1.length)
        {
            for (int i=cur2;i<data2.length;i++)
            {
                res[curn]=data2[i];
                curn++;
            }
        }
        else
        {
            for (int i=cur1;i<data1.length;i++)
            {
                res[curn]=data1[i];
                curn++;
            }
        }
        return res;
    }
    
}

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