I am having hard time understand how DLDAG is a challenge problem. we have: "The score for each test file is 10⋅(C/S)2, where C is the number of steps in which you deleted exactly 2 vertices. The final score of your submission is equal to the sum of scores for each test file." On the other hand we know that at each step we can delete at most 2 vertices. And question asks us to find S to be the minimum number of steps required (and we have to print S to get AC) then isn't C is n  S? asked 15 Dec '18, 13:07
