Output not according to the statement

#1

In the case
qwerty asdfgh qazxsw
qas

the anser given is qazxsw , which is not a substring. Please clarify

#2

@pswaldia1
hello pradeep ,
image
qazxs is smallest length substring that contains all character of string qas thats why answer is qazxs

#3

Ok. I got it . Thanks