Heap Sort

import java.util.Scanner;
public class HeapSort {
    public static int[] vertex;
    public static int n;
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        System.out.println("please enter vertex number");
        n=sc.nextInt();
        vertex=new int[n+1];
        System.out.println();
        System.out.println("please enter the inputs");
        for(int j=1;j<=n;j++){
            vertex[j]=sc.nextInt();
        }
       heapSort(vertex);
       printHeap();
    }
   public static void heapify(int i,int n){
       int l=left(i);
       int r=right(i);
       int largest=i;
       if (l<=n && vertex[l]>vertex[i]){
           largest=l;
       }
       if(r<=n && vertex[r]>vertex[largest]){
           largest=r;
       }
       if(i!=largest){
           swap(i,largest);
           heapify(largest,n);
       }
    }
   public static int left(int i){
       return 2*i;
   }
    public static int right(int i){
        return 2*i+1;
    }
    public static void buildHeap(){
        for(int i=n/2;i>0;i--){
            heapify(i,n);
        }
    }
    public static void heapSort(int[] v){
        buildHeap();
        for(int i=n;i>1;i--){
            swap(1,i);
            n--;
            heapify(1,i-1);
        }
    }
    public static void swap(int i,int j){
        int temp= vertex[i];
        vertex[i]=vertex[j];
        vertex[j]=temp;
    }
    public static void printHeap(){
        System.out.println("The sorted List");
        for(int p=1;p<vertex.length;p++){
            System.out.print(vertex[p]+"\t");
        }

}
}