what is Subsequence?

Can someone explain the subsequences of an array? whatever i understood and read on geeksforgeeks for array {1,2} its subsequences are {1},{2},{1,2}. Hence for subsequence {1,2} its elements sum is 1+2=3 but in for this Ques they are not considering it subsequence as explained in first example.

Don’t ask question clarification of a long challenge in discuss… you can ask it to admin in comments below the problem…

Can’t answer your query about long challenge question as it is a live contest… but can answer what is subsequence as it has nothing to do with long challenge
subsequence of specific length let’s say k simply means picking k elements from an array and not changing the order…
9 8 1 2 3 4 5 6
9 1 2 4 7
8 2 3 5 6
9 8
are valid subsequences
8 9
2 8 5 3 6
1 9 2 4 7
are not valid

couldn’t reply you anything specifically about long challenge… be smart man… don’t ask stuff including word long challenge… u can even ask what is subsequence without mentioning long challenge… this is a general doubt…

Actually till now there have been more than 2 years in participating in codechef challenge. whenever i asked for explanation in any question i have never got any clarification. This system of codechef is really very hectic either they reply very late or never reply.In other coding sites like Hackerrank , hackerearth at least they reply immediately.

yeah but it doesn’t mean you can break rules… mail or write on Invitation to july long challenge…

I got replies in short contests immediately…

do other platforms have long contests ? I m asking this cuz i wanna participate too…

hackerrank week of code and Hackerearth Monthly long circuit contests.