Java-Projects/merge_sort.java at main · FirmanKurniawan/Java-Projects · GitHub

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import java.util.Arrays;


public class Main {


  public static void main(String[] args) {

    System.out.println("mergesort");


    int[] input = { 87, 57, 370, 110, 90, 610, 02, 710, 140, 203, 150 };

    System.out.println("array before sorting");

    System.out.println(Arrays.toString(input));


    mergesort(input);

    System.out.println("array after sorting using mergesort algorithm");

    System.out.println(Arrays.toString(input));

  }


  public static void mergesort(int[] input) {

    mergesort(input, 0, input.length - 1);

  }


  private static void mergesort(int[] input, int start, int end) {


    int mid = (start + end) / 2;
    if (start < end) {
      mergesort(input, start, mid);
      mergesort(input, mid + 1, end);
    }


    int i = 0, first = start, last = mid + 1;

    int[] tmp = new int[end - start + 1];

    while (first <= mid && last <= end) {

      tmp[i++] = input[first] < input[last] ? input[first++] : input[last++];
    }

    while (first <= mid) {

      tmp[i++] = input[first++];

    }

    while (last <= end) {

      tmp[i++] = input[last++];

    }

    i = 0;

    while (start <= end) {

      input[start++] = tmp[i++];

    }

  }

}