Help me in solving CHEFA problem

My issue

Can anyone help me solve this, please!

My code

/* package codechef; // don't place package name! */

import java.util.*;
import java.lang.*;

/* Name of the class has to be "Main" only if the class is public. */
class Codechef
	public static void main (String[] args) throws java.lang.Exception
		// your code goes here
		Scanner sc = new Scanner(;
		int t = sc.nextInt();
		for(int j=0; j<t; j++){
		    int n = sc.nextInt();
		    int[] arr = new int[n];
		    for(int i=0; i<n; i++){
		        arr[i] = sc.nextInt();
		    int max_sum = 0;
		    for(int i=n-1; i>=0; i=i-2){
		        max_sum = max_sum + arr[i];

Learning course: Sorting using Java
Problem Link: CodeChef: Practical coding for everyone

use long data type because constraints is high , rest of your code is absolutely correct.