摘要：
Several currency exchange points are working in our city. Let us suppose that each point specializes in two particular currencies and performs exchang 阅读全文
摘要：
Description Oh those picky N (1 <= N <= 50,000) cows! They are so picky that each one will only be milked over some precise time interval A..B (1 <= A 阅读全文
摘要：
One cow from each of N farms (1 ≤ N ≤ 1000) conveniently numbered 1..N is going to attend the big cow party to be held at farm #X (1 ≤X ≤ N). A total 阅读全文