摘要：
Description Astronomers often examine star maps where stars are represented by points on a plane and each star has Cartesian coordinates. Let the leve 阅读全文
摘要：
Description For the daily milking, Farmer John's N cows (1 ≤ N ≤ 50,000) always line up in the same order. One day Farmer John decides to organize a g 阅读全文