摘要:
n children are standing in a circle and playing a game. Children's numbers in clockwise order form a permutation a1, a2, ..., an of length n. It is an 阅读全文
摘要:
There are n students who have taken part in an olympiad. Now it's time to award the students. Some of them will receive diplomas, some wiil get certif 阅读全文
摘要:
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