Help me in solving CONCUSSIVE problem

My issue

I am writing the same code but it provide the different output but according to given constraints its output is true.

My code

import java.util.*;
import java.lang.*;
import java.io.*;
class Codechef
{
	public static void main (String[] args) throws java.lang.Exception
	{
		Scanner in=new Scanner(System.in);
		int t=in.nextInt();
		while(t-->0){
		    int n=in.nextInt();
		    int[] a=new int[n];
		    for(int i=0;i<n;i++) a[i]=in.nextInt();
		    Arrays.sort(a);
		    if(a[0]==a[n-1]) System.out.println(-1);
		    else{
		        int i=2,j=n-2;
		        System.out.print(a[0]+" "+a[n-1]+" "+a[1]+" ");
		        while(i<=j){
		            if(i==j) System.out.print(" "+a[j--]);
		            else System.out.print(a[j--]+" "+a[i++]);
		        }
		        System.out.println();
		    }
		}
	}
}

Problem Link: CONCUSSIVE Problem - CodeChef

@siatharva
your logic is not right .
This is my c++ code .
Plzz refer it for better understanding of the logic.

#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#include<algorithm>
#include<numeric>

using namespace std;
typedef long long int lli;
using namespace __gnu_pbds;
template<class T> using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
//typedef long long int lli;
//typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> multi_pbds;
//typedef tree<pair<int , int>, null_type, less<pair<int ,int>>, rb_tree_tag, tree_order_statistics_node_update> pbdsp;
//typedef tree< int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> pbds;
#define nl "\n";
#define fastio ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define db long double
#define prq priority_queue<lli>
#define psq priority_queue<lli,vector<lli>,greater<lli>>
#define mod 1000000007
#define lb lower_bound
#define ub upper_bound
#define vlli vector<lli>
#define mslli multiset<lli>
#define inf 1e17
#define sp " "
#define pb push_back
#define pie 3.14159265358979323846
#define test lli t; cin>>t; while(t--)

int32_t main()
{
   #ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    test{
        lli n,ch=0;
        cin>>n;
        lli a[n];
        for(lli i=0;i<n;i++)
        {
            cin>>a[i];
        }
        sort(a,a+n);
        lli b[n];
        lli j=0;
        for(int i=0;i<n;i+=2)
        {
            b[i]=a[j];
            j++;
        }
        for(int i=1;i<n;i+=2)
        {
            b[i]=a[j];
            j++;
        }
        for(int i=1;i<n-1;i++)
        {
            if(b[i]>b[i-1]&&b[i]>b[i+1])
            {
                continue;
            }
            else if(b[i]<b[i-1]&&b[i]<b[i+1])
                continue;
            else
            {
                ch=1;
            }
        }
        if(ch)
        {
            j=0;
            for(int i=1;i<n;i+=2)
            {
                b[i]=a[j];
                j++;
            }
            for(int i=0;i<n;i+=2)
            {
                b[i]=a[j];
                j++;
            }
            for(int i=1;i<n-1;i++)
            {
                if(b[i]>b[i-1]&&b[i]>b[i+1])
                {
                    continue;
                }
                else if(b[i]<b[i-1]&&b[i]<b[i+1])
                    continue;
                else
                {
                    ch=2;
                }
            }
            if(ch==1)
            {
                for(int i=0;i<n;i++)
                {
                    cout<<b[i]<<" ";
                }
            }
            else
                cout<<-1;
        }
        else
        {
            for(int i=0;i<n;i++)
            {
                cout<<b[i]<<" ";
            }
        }
        cout<<endl;
    }

}