I am bit confuse can someone help?

[cubefreak777]

test-cases for this problem were weak. He discussed it pretty well in this post.

LUNCHTIM - Editorial

It clearly states that Proper testing was not done on this problem before the contest started. The worst input for an O(N^2) solution is N = 10^5 and a_i = k\ \forall\ i\isin[1, N], where k is some constant. If they had tested this input against an O(N^2) solution, there would have not been such a huge number of accepted submissions past night. It is not fair to rejudge these submissions because the contest ended. If they (organisers) had realised about it during the contest and made an announc…