摘要：A supply chain is a network of retailers（零售商）, distributors（经销商）, and suppliers（供应商）-- everyone involved in moving a product from supplier to customer 阅读全文

摘要：Some scientists took pictures of thousands of birds in a forest. Assume that all the birds appear in the same picture belong to the same tree. You are 阅读全文

摘要：When register on a social network, you are always asked to specify your hobbies in order to find some potential friends with the same hobbies. A socia 阅读全文

摘要：A supply chain is a network of retailers（零售商）, distributors（经销商）, and suppliers（供应商）-- everyone involved in moving a product from supplier to customer 阅读全文

摘要：A family hierarchy is usually presented by a pedigree tree. Your job is to count those family members who have no child. Input Specification: Each inp 阅读全文