Iterate 2 times unnecessarily causes the script to be more inefficient...
Using less lines of code does not mean writting good code...

For those who did not resolve it that way... At the end of the day those like us who resolved this challenge with an actual algorithm, are the ones who create built-in methods. Actually built-in functions are just a mask hiding a larger code and guess what... Built-in methods might be much more unefficient than a customized algorithm...

Less lines of code does not mean good code