A maximal subarray

The input is an array of numbers, e.g. arr = [1, -2, 3, 4, -9, 6].

The task is: find the contiguous subarray of arr with the maximal sum of items.

Write the function getMaxSubSum(arr) that will find return that sum.

For instance:

getMaxSubSum([-1, *!*2, 3*/!*, -9]) = 5 (the sum of highlighted items)
getMaxSubSum([*!*2, -1, 2, 3*/!*, -9]) = 6
getMaxSubSum([-1, 2, 3, -9, *!*11*/!*]) = 11
getMaxSubSum([-2, -1, *!*1, 2*/!*]) = 3
getMaxSubSum([*!*100*/!*, -9, 2, -3, 5]) = 100
getMaxSubSum([*!*1, 2, 3*/!*]) = 6 (take all)

If all items are negative, it means that we take none (the subarray is empty), so the sum is zero:

getMaxSubSum([-1, -2, -3]) = 0

Please try to think of a fast solution: O(n²) or even O(n) if you can.

857 B Raw Blame History

A maximal subarray

857 B

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