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题目链接： You are given a picture consisting of nn rows and mm columns. Rows are numbered from 11 to nn from the top to the bottom, columns are numbered f 阅读全文
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B. Letters Shop time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output B. Letters Shop time lim 阅读全文
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Note that this is the first problem of the two similar problems. You can hack this problem only if you solve both problems. You are given a tree with 阅读全文