MergeSortAlgorithm_Faculty

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package cse221;

/**
 *
 * @author acer
 */
public class MergeSortAlgorithm {
    public static int [] a={2,4,1,6,8,5,3,7};

    public static void main(String[] args) {



        mergeSort(a,0,a.length-1);
        System.out.println();
        for(int i:a){
            System.out.print(i+",");
        }


    }
    public  static void mergeSort(int [] a,int p,int r){
        if(p<r){
            int q=(int)Math.floor((p+r)/2);
            mergeSort(a,p,q);
            mergeSort(a,q+1,r);
            merge(a,p,q,r);
        }
    }

    public static void merge(int []a,int p,int q,int r){
        int n1=q-p+1;
        int n2=r-q;
        int []L=new int[n1+1];
        int []R=new int [n2+1];

        for(int i=0;i<n1;i++){
            L[i]=a[p+i];
        }
        for(int j=0;j<n2;j++){
            R[j]=a[q+j+1];
        }
        L[n1]=7777;
        R[n2]=7777;

        int i=0;
        int j=0;

        for(int k=p;k<=r;k++){
            if(L[i]<R[j]){
                a[k]=L[i];
                i++;
              }
            else{
                a[k]=R[j];
                j++;
            }

        }
    }
}