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多重集合的排列定理:设S是多重集合,他有k种不同类型的对象,每一种类型的有限重复数是n1,n2,n3,…nk。设S的大小为n=n1+n2+n3+…nk。则S的n排列数目为n!/(n1!n2!n3!…nk!)证明:先从S中选出n1个位置放a1,有C(n,n1)种放法,再选出n2个位置放a2,有C(n- 阅读全文
posted @ 2017-03-10 15:49
TRTTG
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Layout http://poj.org/problem?id=3169 Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 10880 Accepted: 5233 Description Like everyone else, 阅读全文
posted @ 2017-03-10 11:45
TRTTG
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Intervals http://poj.org/problem?id=1201 Time Limit: 2000MS Memory Limit: 65536K Description You are given n closed, integer intervals [ai, bi] and n 阅读全文
posted @ 2017-03-10 11:31
TRTTG
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Integer Intervals http://poj.org/problem?id=1716 Time Limit: 1000MS Memory Limit: 10000K Description An integer interval [a,b], a < b, is a set of all 阅读全文
posted @ 2017-03-10 11:27
TRTTG
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