I’m new to codechef. Please assist me if its repeative post.

I’m C++/STL developer and looking for:

finding unique numbers from series on integer number wihtout changing its order.
e.g:
i/p: 10,4,3,6,1,0,4,4,4,10,5,9,0,6,15,…
o/p(expected result): 10,4,3,6,1,0,5,9,15,…

Constraint:

time complexity should not be worst(N^2). Need to solve it in less time.

memory is adequate.

appricieate, if you can explain about STL containers or algorithm I must use to resolve this problem.