Codeforces 455E - Function

Problem Statement:
http://codeforces.com/contest/455/problem/E

Summary:
Given a function f(i, j) = min (f(i-1, j), f(i-1, j-1)) + a[j], where f(1, j) = a[j], and m queries (m <= 10^5) in the form (i, j), compute f(i, j) of each queries.

Codeforces 678F - Lena and Queries

Problem Statement:
http://codeforces.com/contest/678/problem/F

Summary:
There are n <= 300000 queries of the form: add lines ax+b, remove line ax+b, and the maximum intersection between vertical line x = q and all lines.