摘要:
Some definition A word u is a prefix of a word w is there exists a word v (possibly empty) such that $w=uv$ A word v is a suffix of a word w is there 阅读全文
摘要:
I'm so stupid...I have Waed so many times on this problem... 这是神奇的Dilworth定理的一个应用,可以自行google一下,非常amazing的一个theory 以木头的一个性质(例如长度升序排列),之后将思路转化为了最长下降子序列( 阅读全文