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C. Short Program time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Petya learned a new pro 阅读全文
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B. Ralph And His Magic Field time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Ralph has a 阅读全文
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The ant Welly now dedicates himself to urban infrastructure. He came to the kingdom of numbers and solicited an audience with the king. He recounted h 阅读全文
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Consider a un-rooted tree T which is not the biological significance of tree or plant, but a tree as an undirected graph in graph theory with n nodes, 阅读全文