The 2018 Egyptian Collegiate Programming Contest was held yesterday this was a problem from it where he asks for

Where n<=10^5 and a[i]<=10^5 answer should be printed %10^9+7

I would appreciate any help in solving this problem and thanks in advance

i have been on cf for about 7 weeks most of the problems i solve are problems A division 2 and some times i cant solve them now i am at a stage where i am feeling that i cant solve any problem can any one give me some tips to improve myself as i dont know what to do and sorry for poor english