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import java.io.*;
public class merge
{
void merge(int a[],int l,int mid,int h)
{
int i=l,j=mid+1,k=l;
int c[]=new int[50];
while((i<=mid)&&(j<=h))
{
if(a[i]<=a[j])
c[k++]=a[i++];
else
c[k++]=a[j++]; // l=low
} // h=high
while(i<=mid)
c[k++]=a[i++];
while(j<=h)
c[k++]=a[j++];
for(i=l;i<k;i++) // necessary loop
a[i]=c[i];
}
void merge_sort(int a[],int l,int h)
{
int mid;
if(l<h)
{ mid=(l+h)/2;
merge_sort(a,l,mid);
merge_sort(a,mid+1,h);
merge(a,l,mid,h);
}
}
public void main(String args[])throws IOException
{
System.out.print("\nProgram to sort array using merge sort : \n");
int n,i;
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
System.out.print("\nEnter array capacity : ");
n=Integer.parseInt(br.readLine());
int a[]=new int[n];
for(i=0;i<n;i++)
a[i]=(int)(Math.random()*100); // Generates random numbers
System.out.print("\nArray before sorting : ");
for(i=0;i<n;i++)
System.out.print(a[i] + " ");
merge_sort(a,0,n-1);
System.out.print("\nArray after sorting : ");
for(i=0;i<n;i++)
System.out.print(a[i] + " ");
}
}
Recursive Merge Sort in Java
