Hi Codeforces! Problems : https://dmoj.ca/problem/ioi02p4 I read the editorial and their definition of dp[i] = dp[j] + ( S + sum( t[k] ) ) * sum( f[k] ) with j < k <= i but the statement tell that to calculate batch i, our euquation is dp[i] = dp[j] + ( t + S + sum( t[k] ) ) * sum( f[k] ) with j < k <= i and t is the time needed to solve the previous batches. Can somebody explain it? I would be extremely grateful.