Maximum sum of sub-array using Kadane's Algorithm in Java

Question

This is a problem statement from geeks for geeks (link : https://practice.geeksforgeeks.org/problems/kadanes-algorithm/0 )

My code is working fine as per the Compile & test option. But when I try to submit, it throws error about failure for multiple test cases.

Could anyone help me with this?

CODE:

import java.io.IOException;
import java.io.InputStreamReader;
import java.io.BufferedReader;


public class Kadane

{
public static void main(String[]args) throws IOException,NumberFormatException

{
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

    System.out.println("Enter the number of test cases");
    int T = Integer.parseInt(br.readLine());

    for(int t=0 ; t<T ; t++)
    {
        int N,a=0;
        int sum1=0,maxsum=-2147483648,kadanesum=-2147483648;

        System.out.println("Enter the size of array : ");
        N =  Integer.parseInt(br.readLine());
        int arr[] = new int[N];

        System.out.println("Enter the array elements separated by space");
        String S = new String(br.readLine());
        String elem[] = S.split(" ");

        for(String e:elem)
        {
            arr[a] = Integer.parseInt(e);
            a++;
        }

        for(int i=0 ; i<N ; i++)
        {
            for(int j=i ; j<N ; j++)
            {
                sum1 = sum1 + arr[j];
                if(maxsum<sum1)
                {
                    maxsum=sum1;

                }
            }
            if(maxsum>kadanesum)
            {
                kadanesum=maxsum;
            }
            sum1=0;
            maxsum=-2147483648;
        }

        System.out.println("\tKadane Sum = " + kadanesum);

    }           
}
}

My code link : https://ide.geeksforgeeks.org/tXNHh28A0D

My input : 5(number of test cases)

3(array size)

1 2 3(array elements)

5

1 2 3 -2 5

10

2 9 3 -10 -20 34 28 -50 30 -1

7

4 5 -10 -50 3 9 8

8

8 9 8 -25 25 1 2

My output : Enter the number of test cases

Enter the size of array : Enter the array elements separated by space Kadane Sum = 6

Enter the size of array : Enter the array elements separated by space Kadane Sum = 9

Enter the size of array : Enter the array elements separated by space Kadane Sum = 62

Enter the size of array : Enter the array elements separated by space Kadane Sum = 20

Enter the size of array : Enter the array elements separated by space Kadane Sum = 28

I get the below error message when submitting my code :

Wrong Answer. !!!Wrong Answer Possibly your code doesn't work correctly for multiple test-cases (TCs). The first test case where your code failed:

Input:(As per website) 3 1 2 3

Its Correct output is: 6

I have used this same input in my input test cases(test case 1) and the output is same as expected.

Could anyone help me to optimize the code using StringBuffer?

Answer 1

The output should be the sum:

System.out.println(kadanesum);

And not the message you wrote:

System.out.println("\tKadane Sum = " + kadanesum);

And as Rahul pointed out, you also need to remove the other messages such as:

System.out.println("Enter the array elements separated by space");