instead of map(val => Number(val)) you can just write map(Number)

"one distinct country" in description is Ukraine

if array were huge you would do it three times too ?

You have to think, but it all depends on the result you want to get. Everything is fine so check all the values and check them

What would you do if there were (a, b, c, d, e, f, g, h....) ?

I think if one of calculated "min" is 0 it would be better to stop iteration because "arr" can be huge

I found it. Thanx

Not sure if linking comments works here but there is a reply to MrSoto from a few years back where I expand the code with line by line explanation. Can expand on that if it's unclear, although it's been a while :-)

Would you mind to explain what your code is doing ?

you should read about graph theory

you must return NEW instance of Vector but you change input

Why this kata is tagged as "OBJECT-ORIENTED PROGRAMMING" ?