can you submit external contest’s answer’s after it’s over just to check whether am i right or wrong?
Yes. you can. But it takes 2 to 3 days, by codechef to make those problems visible.
thank u 
You can find the external contest problems in PEER section of practice problems.
alternatively u can send a mail to CC to make the problems available in the PEER section…they will do it within a day or two!!!