摘要：
Starry NightIOI 98High up in the night sky, the shining stars appear in clusters of various shapes. Aclusteris a non-empty group of neighbouring stars... 阅读全文
摘要：
Fencing the CowsHal BurchFarmer John wishes to build a fence to contain his cows, but he's a bit short on cash right. Any fence he builds must contain... 阅读全文