Can someone please explain why codechef compiler is declaring this code has a wrong output while i am getting the correct one.

I am using IntelliJ as my platform.
The question can be found here:https:“www.codechef.com/problems/SNAKPROC.”

My Code:

import java.util.Scanner;

class SnakeCounter {

int l;

int h=-1;int t=-1;

int k=-1;

String arr[];

void accept()

{

    int co=-1;

    Scanner sc=new Scanner(System.in);

    int T;

    T=sc.nextInt();

    sc.nextLine();

    arr=new String[T];

    while(T!=0)

    {

        l=sc.nextInt();

        sc.nextLine();

        String s=sc.nextLine();

        int c=-1;

        for(int i=0;i<l;i++)

        {

            if(s.charAt(i)=='H')

            {

                h=h+1;

                if(c==1)

                {

                    k=0;

                    break;

                }

                c=1;

            }

            if(s.charAt(i)=='T')

            {

                t=t+1;

                if(c==0)

                {

                    k=0;

                    break;

                }

                c=0;

            }

        }

        if(k==0)

            arr[++co]="Invalid";

        else if(h!=t)

            arr[++co]="Invalid";

        else

            arr[++co]="Valid";

        T=T-1;

        h=-1;t=-1;k=-1;c=-1;

    }

}

void display()

{

   for(int i=0;i<arr.length;i++)

       System.out.println(arr[i]);

}

public static void main(String args[])

{

    SnakeCounter obj=new SnakeCounter();

    obj.accept();

    obj.display();

}

}

AND it is giving the correct output for the given input example.

//