Merge sort (JAVA)

package org.rev.algorithm;/** *  merge sort, belongs to the Exchange sort, the time complexity is the algorithm complexity 0 (n log n), is slower than the fast sort, but stable.  *  * 1.  recursively splits a sequence into multiple ordered sub-sequences.  *  * 2.  recursively merges these sub-sequences into a complete subsequence.  *  */public class mergesort {  public static void main (String[] args)  {    int[] data = {39, 11, 38, 97,  86, 37, 12, 4, 51, 18};    //  Merge Sort      mergesort ms = new mergesort ();     ms.sort (data);     system.out.println ("After sorting:");     ms.printdata (data);  }   Public void sort (Int[] data)  {    if  (data.length >  0)  { // length is 0, it cannot be reduced by 1.       mergesort (data, 0, data.length - 1);  &nbSp;  }  }  public void mergesort (Int[] data, int left,  int right)  {    if  (left < right)  {       int middle =  (left + right)  / 2;       system.out.println ("Left is:"  + left +  ",  right is:"  + right +  ",   middle is:"  + middle           +  ",   data["  + middle +  "]="  + data [Middle]);       mergesort (Data, left, middle); //  recursion to the left        mergesort (data, middle + 1, right); //  recursion to the right        merge (data, left, middle, right); //  merge       &nBsp;printdata (data);    }  }  /**   *  merges two arrays, Merging the first two arrays is ordered, and the merged arrays are also ordered.    *    *  @param  data  Array Objects    *  @param  left  index of the first element of the left array    *  @param  middle  The index of the last element of the left array, middle+1 is the index of the first element of the right array    *  @param  right  Index of the last element of the right array    */  private void  merge (int[] data, int left, int middle, int right)  {     //  Temporary Arrays     int[] tmpArr = new int[data.length];     //  index of the first element on the right side     int mid = middle + 1;     // tmp  temporary variables, caches the index of the first element of the left array     int tmp =  left;    // third  records the index of a temporary array     int third = left;    while  (left <= middle && mid <=  right)  {      //  Select a smaller number from two arrays to put in a temporary array        if  (Data[left] <= data[mid])  {         tmparr[third++] = data[left++];      } else {         tmpArr[third++] = data[mid++];       }    }    //  put the rest of the parts into a temporary array     while   (Left <= middle)  {      tmparr[third++] = data [left++];    }    while  (mid <= right)  {       tmpArr[third++] = data[mid++];    }     //  copy the temporary array back to the original array     while  (tmp <= right)  {      data[tmp]  = tmpArr[tmp++];    }  }  /*   *  Print data from an output array    */  private void printdata (Int[] data)  {     for  (int i = 0; i < data.length; i++)  {       system.out.print (data[i] +  "\ T");    }     system.out.println ();   }}

Merge sort (JAVA)