Yes after Jan 2018 in any month u have to give long challenge at codechef its a monthly contest which is conducted between first 15 days depending on your best score of any Long challenge u have to submit your score and answer as printed (whatsoever they want code etc....) at the time of interview .
these are monthly coding contest which are conducted by codechef Feb long chanllege check out this link https://www.codechef.com/FEB18
Number of question >>8-10 (it can vary )
u can practice previous long challenge or other past contest
https://www.codechef.com/contests
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