merge.java

import java.util.Scanner ;
public class merge{
public static void merge(int arr[],int left,int right){
if(left<right){
int mid=left+(right-left)/2;
merge(array,left,mid);
merge(arr,mid+1,right);
merge(arr,left,mid,right);
}
}
public static void mer(int[] arr,int left,int mid,int right){
int n1=mid-left+1;
int n2=right-mid;
int[] leftarr=new int [n1];
int[] rightarr=new int[n2];
for(int i=0;i<n1;i++){
leftarr[i]=arr[left+1];

}
for(int j=0;j<n2;++j){
rightarr[j]=arr[mid+1+j];
}
int i=0,j=0,k=left;
while(i<n1 && j<n2){
if(leftarr[i]<=rightarr[j]){
arr[k]=leftarr[i];
++i;
}
else{
arr[k]=rightarr[j];
++j;
}
++k;

while(i<n1){
arr[k]=leftarr[i];
++i;
++k;
}
while(j<n2){
arr[k]=rightarr[j];
++j;
++k;
}
}
public static void main(String[] args){
Scanner scanner=new Scanner(System.in);
System.out.print("enter a number of elements");
int n=scanner.nextInt();
int[] arr=new int[n];
System.out.print("enter a elements:");
for(int i=0;i<n;i++){
arr[i]=scanner.nextInt();
}
System.out.print("entered array:");
for(int num :arr){
System.out.print(num+" ");
}
System.out.println();
merge(arr,0,n-1);
system.out.print("sorted array:");
for(int num:arr){
System.out.print(num+" ");
}
System.out.println();
scanner.close();
}
}