notes:
* Thanks Tomek for pointing out the iteration problem and possible efficient solutions.

* When c is large, mid * mid * mid will overflow but the algorithm still works.

* We’ve addressed negative numbers, numbers in (0, 1), overflow problems, absolute and relative error problems.
* Some tests for your own code -1, 0, 1, 2, 8, 0.001, 1e30, 1e60
* In practice faster methods like Newton Rapson method are used.

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