this sollution doesn't pass tests now becouse of this reason

now he has deleted his account

got it. thank you very much!

have question about comparison in reduce:
if it's false then method takes next object in 'c', but 'a' is still first object?
and if it's true then method takes 'c' in 'a' and next object to 'c'?

how does "v in seen" works? is it just check of property in object? and if it's false then u add char to object and a filter return this char too?

JavaScript

There is no tests for several whitespaces between each word, and almost everyone uses .trim(). But it says in description ("while ensuring there is exactly one space between each word").

u need 'baab' from the example "zzbaabcd", then it's 4