Divide_Conquer.java

public class Divide_Conquer{
    public static void printArr(int arr[]){
        for(int i=0;i<arr.length;i++){
            System.out.print(arr[i]+" ");
        }
        System.out.println();
    }
public static void mergesort(int arr[],int si,int ei) {
    if(si>=ei){
            return;
        }
        int mid=si+(ei-si)/2;
        mergesort(arr, si,mid);
        mergesort(arr, mid+1,ei );
        merge(arr,si,mid,ei);  
    }
public static void merge(int arr[],int si,int mid,int ei){
        int temp[]=new int[ei-si+1];
        int i=si;
        int j=mid+1;
        int k=0;
        while(i<=mid && j<=ei ){
            if(arr[i]<arr[j]){
                temp[k]=arr[i];
                i++;
            }
            else{
                temp[k]=arr[j];
                j++;
            }
            k++;
        }
        while(i<=mid){
            temp[k++]=arr[i++];
        }
        while(j<=ei){
            temp[k++]=arr[j++];
        }
        for(k=0,i=si;k<temp.length;k++,i++){
            arr[i]=temp[k];

        }




    }
public static void main(String[] args) {
        int arr[]={6,3,9,5,2,8}; 
        mergesort(arr, 0, arr.length-1);
        printArr(arr);

    }

}