30 lines
No EOL
857 B
Markdown
30 lines
No EOL
857 B
Markdown
importance: 2
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---
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# A maximal subarray
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The input is an array of numbers, e.g. `arr = [1, -2, 3, 4, -9, 6]`.
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The task is: find the contiguous subarray of `arr` with the maximal sum of items.
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Write the function `getMaxSubSum(arr)` that will find return that sum.
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For instance:
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```js
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getMaxSubSum([-1, *!*2, 3*/!*, -9]) = 5 (the sum of highlighted items)
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getMaxSubSum([*!*2, -1, 2, 3*/!*, -9]) = 6
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getMaxSubSum([-1, 2, 3, -9, *!*11*/!*]) = 11
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getMaxSubSum([-2, -1, *!*1, 2*/!*]) = 3
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getMaxSubSum([*!*100*/!*, -9, 2, -3, 5]) = 100
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getMaxSubSum([*!*1, 2, 3*/!*]) = 6 (take all)
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```
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If all items are negative, it means that we take none (the subarray is empty), so the sum is zero:
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```js
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getMaxSubSum([-1, -2, -3]) = 0
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```
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Please try to think of a fast solution: [O(n<sup>2</sup>)](https://en.wikipedia.org/wiki/Big_O_notation) or even O(n) if you can. |