20191201
有的时候再多的想象也是抵不过亲眼的见证，我对昨晚的攀岩比赛就是这么感觉的。 看见比我小十几岁的孩子拥有那么高超的攀岩技术，可以轻松克服近半米的身高劣势（当然也可以说我靠近半米的身高优势才能在比赛中苟延残喘），虽然之前在网上见识过大概了，但亲眼看见还是深深叹服一线城市小孩的教育素养，抛开他们拥有的场地、父母的经济时间资源支持等等，最让我印象深刻的是他们在比赛中表现出来的那种聪明而又顽强的拼搏精神，我相信这也是最宝贵的优势，毕竟在我的儿时，这种气场就已经是神级的存在了。也有可能只是我自作多情的管中窥豹，不过我真的对「把孩子放在一线城市成长」产生了些许阴影，我没有自信拥有足够的资源让我的孩子在这种激烈的环境中获取足够的快乐。
Codeforces #1113C
1113C C. Sasha and a Bit of Relax 题意 给一个数组，然后求满足 的[l, r]子序列有多少个，其中表示异或计算。 思路 关键点在于如果满足条件的[l,r]存在，那么
Logistic Regression
逻辑斯谛回归因为其易于实现，可解释性强，已经成为了工业界应用最广泛的机器学习算法。这篇文章主要讨论的是二项逻辑斯谛回归 (binominal logistic regression)，以下简称LR。
POJ3020
POJ3020 Antenna Placement Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 10821 Accepted: 5324 Description The Global Aerial Research Centre has been allotted the task of building the fifth generation of mobile phone nets in Sweden. The most striking reason why they got the job, is their discovery of a new, highly noise resistant, antenna. It is called 4DAir, and comes in four types. Each type can only transmit and receive signals in a direction aligned with a (slightly skewed) latitudinal and longitudinal grid, because of the interacting electromagnetic field of the earth. The four types correspond to antennas operating in the directions north, west, south, and east, respectively. Below is an example picture of places of interest, depicted by twelve small rings, and nine 4DAir antennas depicted by ellipses covering them.