Unable to find SubArrays with MaxSum?

#1

Problem -
I have used the cumulative approach for the following code in Java to find subarrays with maximum sum but I am not getting Correct Output.

Can anyone guide me how to correct this?

Solution I tried

    int maxSum = 0;
    int[] cumSum = new int[input.length];
    cumSum[0] = input[0];
    for (int i = 1; i < input.length; i++) {
        cumSum[i] = cumSum[i - 1] + input[i];
    }
    //For each subArray Calculate Cumilative Sum
    for (int i = 0; i < input.length; i++) {
        int currentSum = 0;
        for (int j = i; j < input.length; j++) {
            if (i - 1 >= 0)
                currentSum = cumSum[j] + cumSum[i - 1];
            else
                currentSum = cumSum[j];
            System.out.println("Current Sum is " + currentSum);
            maxSum = Math.max(cumSum[i], currentSum);
        }
    }

Input
1,2,3,4
Output
16

#2

You are doing it wrong.

if (i - 1 >= 0)
currentSum = cumSum[j] + cumSum[i - 1];

This adds extra values to your answer.
Think of some other approach

#3

This can even be done in O(n) using the Kadane’s algorithm