Data structure Merge sort Java implementation

Thought:

assuming the initial sequence rightNRecords, the first of theseNa record asNordered subsequence, each sub-sequence has a length of1, and then 22 merge, GetN/2Rounding up a length of2(Nis odd, the length of the last sequence is1) ordered sub-sequences. On this basis, the length of the2the ordered sub-sequences of 22 are merged to get several lengths of4ordered sub-sequences. So repeat until you get a length ofNordered sequence.

Stability: Stable

Calculation of time complexity:

1. The size of the array is a power of 2, so that it can always be divisible by 2. Assume a K-square of 2, or K=LOG2 (n).

2. Each time we select a value that is exactly the median, the array can be divided equally.
   The first layer recursion, need to loop n times to sort well, the second layer of cyclic (N/2) ...
   So there are n+2 (N/2) +4 (N/4) +...+n* (n/n) = N+N+N+...+N=K*N=LOG2 (n) *n
   So the algorithm complexity is O (log2 (n) *n).
   

Code:

 public static void sort (int[] data, int left, int right)  {   system.out.println (left+ ":" +right);  if  (left < right)  {    int center =  (left + right)  / 2;       system.out.println (left+ ":" +center+ ":" +right);   //  recursively    sort the left array ( Data, left, center);       system.out.println (left+ ":" +center+ ":" +right );   //  recursive    sort (data, center + 1, right) to the right array;       //  merged    merge (data, left, center, right );   } } public static void merge (int[] data, int left,  Int center, int right)  {  int[] tmparr = new int[data.length ];  int&nbSp;mid = center + 1;  // third records the index of an intermediate array   int third =  left;  int tmp = left;  while  (left <= center  && mid <= right)  {   //  Remove the smallest of the two arrays into the middle array     if  (Data[left] <= data[mid])  {    tmparr[third++] = data[ left++];   } else {    tmparr[third++] = data[mid++]; The remainder of the    }  }  //  is placed in the middle array in turn   while  (mid <=  right)  {   tmpArr[third++] = data[mid++];  }  while  ( Left <= center)  {   tmparr[third++] = data[left++];  }   //  Copy the contents of the intermediate array back to the original array   while  (tmp <= right)  {    data[tmp] = Tmparr[tmp++];  }  system.out.println (arrays.tostring (data));  }  public  static void main (String[] args)  {  int[] a1 = {5,1,3,4,2};   sort (a1,0,a1.length-1);  }

Data structure Merge sort Java implementation