Challenge - #64 - The Caption's Room
# Enter your code here. Read input from STDIN. Print output to STDOUT k = int ( input ()) lst = list ( map ( int , input ().split())) s1 = set () # unique room no list s2 = set () # room no which appear more than once for i in lst: if i in s1: s2.add(i) else : s1.add(i) s = s1.difference(s2) print (*s)