ZhangMengzhi

摘要： 我们在升级mongodb3.6之后，线上数据库存在大量慢查询，经过分析explain结果发现是query plan阶段耗时过长，于是我先研究了下mongodb3.6的query plan。 query plan机制 现有索引： { "key" : { "c1" : 1.0 }, "name" : " 阅读全文

摘要： Description Edward is the headmaster of Marjar University. He is enthusiastic about chess and often plays chess with his friends. What's more, he bought a large decorativ... 阅读全文

摘要： Description 吉哥又想出了一个新的完美队形游戏！ 假设有n个人按顺序站在他的面前，他们的身高分别是h[1], h[2] ... h[n]，吉哥希望从中挑出一些人，让这些人形成一个新的队形，新的队形若满足以下三点要求，则就是新的完美队形： 1、挑出的人保持原队形的相对顺序不变，且必须... 阅读全文

摘要： Manacher算讲解：（讲得很好，花十几分钟看一下原理然后自己敲模板） http://www.cnblogs.com/biyeymyhjob/archive/2012/10/04/2711527.html 看了上面的讲解，O(n)回文子串（Manacher）算法就大致了解了它的原理，这倒是个比较简单的知识点。 下面看模板题： Desc... 阅读全文

摘要： Description Hzz loves aeroplane chess very much. The chess map contains N+1 grids labeled from 0 to N. Hzz starts at grid 0. For each step he throws a dice(a dice have si... 阅读全文

摘要： Description I used to think I could be anything, but now I know that I couldn't do anything. So I started traveling. The nation looks like a connected bidirecti... 阅读全文

摘要： Description In the battlefield , an effective way to defeat enemies is to break their communication system. The information department told you that there are n... 阅读全文

摘要： Description For the hope of a forever love, Steven is planning to send a ring to Jane with a romantic string engraved on. The string's length should not exceed N. The car... 阅读全文

摘要： Description Biologists finally invent techniques of repairing DNA that contains segments causing kinds of inherited diseases. For the sake of simplicity, a DNA is represe... 阅读全文

摘要： Description There is going to be a party to celebrate the 80-th Anniversary of the Ural State University. The University has a hierarchical structure of employees. It mea... 阅读全文