<?xml version="1.0" encoding="utf-8" ?><rss version="2.0"><channel><title><![CDATA[SandwichBK的博客]]></title><description><![CDATA[]]></description><link>https://blog.youkuaiyun.com/SandwichBK</link><language>zh-cn</language><generator>https://blog.youkuaiyun.com/</generator><copyright><![CDATA[Copyright &copy; SandwichBK]]></copyright><item><title><![CDATA[状压dp 练习]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/131488156</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/131488156</guid><author>SandwichBK</author><pubDate>Thu, 06 Jul 2023 10:42:03 +0800</pubDate><description><![CDATA[i和u应该没法优化。k，上一道菜的口味，取决于上一个吃到菜的人。已知i-1已经吃到了菜，那么上一个吃到菜的人不可能是i-9及之前。同时也不可能是i+8及之前。所以这个人在i−8i7[i-8,i+7]i−8i7内。时间复杂度O14cn27O(14cn2^7)O14cn27j < MAXB;++ j) {if(!++ j) {if(!]]></description><category></category></item><item><title><![CDATA[Atcoder ABC308E~Ex]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/131498274</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/131498274</guid><author>SandwichBK</author><pubDate>Sun, 02 Jul 2023 15:20:12 +0800</pubDate><description><![CDATA[各种M => 各种ME => 各种MEX => ANS.。]]></description><category></category></item><item><title><![CDATA[P5665 [CSP-S2019] 划分]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/131486761</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/131486761</guid><author>SandwichBK</author><pubDate>Sat, 01 Jul 2023 10:11:37 +0800</pubDate><description><![CDATA[只需要在最后用临时高精度变量，]]></description><category></category></item><item><title><![CDATA[[CSP-S 2021] 括号序列]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/131294332</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/131294332</guid><author>SandwichBK</author><pubDate>Mon, 19 Jun 2023 20:27:06 +0800</pubDate><description><![CDATA[小 w 在赛场上遇到了这样一个题：一个长度为n且符合规范的括号序列，其有些位置已经确定了，有些位置尚未确定，求这样的括号序列一共有多少个。身经百战的小 w 当然一眼就秒了这题，不仅如此，他还觉得一场正式比赛出这么简单的模板题也太小儿科了，于是他把这题进行了加强之后顺手扔给了小 c。具体而言，小 w 定义“超级括号序列”是由字符组成的字符串，并且对于某个给定的常数k()(S)SkSABABASBABABA(A)(SA)(AS)例如，若k3，则字符串是符合规范的超级括号序列，但字符串*()]]></description><category></category></item><item><title><![CDATA[Codeforces Round 868 (Div. 2) A~D]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/130450231</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/130450231</guid><author>SandwichBK</author><pubDate>Sun, 30 Apr 2023 20:46:06 +0800</pubDate><description><![CDATA[ABC；D想了一会跳过了；E WA，正解似乎涉及博弈论的定理；F数学期望没看。]]></description><category></category></item><item><title><![CDATA[Codeforces Round 865 (Div. 2)]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/130209504</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/130209504</guid><author>SandwichBK</author><pubDate>Sat, 29 Apr 2023 20:23:18 +0800</pubDate><description><![CDATA[6 problems. ABC过, DE没想出来, F没看.]]></description><category></category></item><item><title><![CDATA[Luogu P5270 无论怎样神树大人都会删库跑路]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/129940250</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/129940250</guid><author>SandwichBK</author><pubDate>Tue, 04 Apr 2023 21:17:37 +0800</pubDate><description><![CDATA[众所周知，神J（Joker）每隔几天就会去成都法中假装上课，实际上是去玩指针。神J可以趁别人不注意掏出指针把自己指到任何位置（生物标本柜里大变活人？），或者把两个人的指针交换一下（成都法中版《你的名字》？），或者对着OJ念系统命令使得OJ随机变慢（mcfx：怎么这CPU睿频后反而变慢了）。神树大人很不满意，因为树必须站在原地，而且神树大人也不会指针。但是神树大人是神，于是他打算把这个宇宙的数据库删了跑路，这样无所事事的神J就只能和神树大人玩牌了。]]></description><category></category></item><item><title><![CDATA[USACO2023Feb Silver]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/129224025</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/129224025</guid><author>SandwichBK</author><pubDate>Tue, 07 Mar 2023 16:04:50 +0800</pubDate><description><![CDATA[把tC​tM​记作CM以便书写。xy满足若干个形如ai​C−xbi​M−y≤ci​的不等式，求xymin​具备单调性，考虑二分答案。设xys, 则不等式化为ai​−bi​x≥ai​Cbi​M−bi​s−ci​, 讨论ai​−bi​的正负，解出x的范围，大于等于或小于等于某个值。这里涉及到除法，我选择实数存储。有多个这样的不等式，可得x的区间mnmx。]]></description><category></category></item><item><title><![CDATA[POJ3237 Tree]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/129057432</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/129057432</guid><author>SandwichBK</author><pubDate>Thu, 16 Feb 2023 11:26:23 +0800</pubDate><description><![CDATA[多组数据注意初始化。]]></description><category></category></item><item><title><![CDATA[POJ2763 Housewife Wind]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/129050404</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/129050404</guid><author>SandwichBK</author><pubDate>Wed, 15 Feb 2023 20:46:01 +0800</pubDate><description><![CDATA[【代码】POJ2763 Housewife Wind。]]></description><category></category></item><item><title><![CDATA[POJ1986 Distance Queries]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/128762606</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/128762606</guid><author>SandwichBK</author><pubDate>Wed, 25 Jan 2023 21:11:40 +0800</pubDate><description><![CDATA[查询两点间路径长，就是把两点间路径split出来，输出splay根上的值。在点上维护以之为根的splay子树上的点权和。将边当作虚点，连接到两个点。]]></description><category></category></item><item><title><![CDATA[Luogu P2590 [ZJOI2008]树的统计]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/128757932</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/128757932</guid><author>SandwichBK</author><pubDate>Tue, 24 Jan 2023 20:33:33 +0800</pubDate><description><![CDATA[一棵树上有n个节点，编号分别为1到n，每个节点都有一个权值w。我们将以下面的形式来要求你对这棵树完成一些操作：I.CHANGE u t: 把结点u的权值改为t。II.QMAX u v: 询问从点u到点v的路径上的节点的最大权值。III.QSUM u v: 询问从点u到点v的路径上的节点的权值和。注意：从点u到点v的路径上的节点包括u和v本身。]]></description><category></category></item><item><title><![CDATA[Luogu P3379 【模板】最近公共祖先（LCA） 重链剖分]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/128757290</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/128757290</guid><author>SandwichBK</author><pubDate>Tue, 24 Jan 2023 18:02:03 +0800</pubDate><description><![CDATA[如题，给定一棵有根多叉树，请求出指定两个点直接最近的公共祖先。]]></description><category></category></item><item><title><![CDATA[SPOJQTREE4 Query on a tree IV]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/128754202</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/128754202</guid><author>SandwichBK</author><pubDate>Mon, 23 Jan 2023 21:47:16 +0800</pubDate><description><![CDATA[对于分出来的每个子树，它的答案是由它再分出来的两个子树中的数据处理得到。然后再往上传，传到最大的那个子树，也就是整棵树。据上文，要维护“子树中白色节点到根的最长距离”。为此要记录所有节点到根的距离，将白色的加入到堆中，颜色作为删除懒标记。边分治处理与树的路径有关的问题。找到一条中心边，删掉它之后树分成两半，使两半的大小尽可能均匀，达到分治降低复杂度的目的。与中心边相连的两个节点p1,p2分别作为两棵子树的根。经过中心边的最长路径，就是左边子树中白色节点到p1的最长距离，加上右边的，加上中心边。]]></description><category></category></item><item><title><![CDATA[HDU4812 Tree]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/128750167</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/128750167</guid><author>SandwichBK</author><pubDate>Sun, 22 Jan 2023 20:36:42 +0800</pubDate><description><![CDATA[please print the lexicographically smallest one.”]]></description><category></category></item><item><title><![CDATA[POJ2114 Boatherds]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/128747521</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/128747521</guid><author>SandwichBK</author><pubDate>Sat, 21 Jan 2023 22:09:26 +0800</pubDate><description><![CDATA[Boatherds Inc. is a sailing company operating in the country of Trabantustan and offering boat trips on Trabantian rivers. All the rivers originate somewhere in the mountains and on their way down to the lowlands they gradually join and finally the single ]]></description><category></category></item><item><title><![CDATA[POJ1741 Tree]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/128743727</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/128743727</guid><author>SandwichBK</author><pubDate>Fri, 20 Jan 2023 21:20:08 +0800</pubDate><description><![CDATA[(x,y)的路径经过rt或不经过rt。经过rt的，就是x-rt-y，即x-rt, y-rt，维护树上每个点到rt的距离并求出符合条件的路径数。这样的情况，就是x,y在一棵子树上。只考虑rt的一个子树上的节点，进行一次如上文的统计答案，得到的就是这样的情况数。一个细节是，找到以v为根的子树的重心rt1后，下面的操作就以rt1为根，还有不经过rt的，所以继续递归，分治，对rt的每个子树进行相同的操作。耗费三个半小时的大好青春，经历21次TLE，我深切地认识到，在图上，rt1并不是rt的子节点。]]></description><category></category></item><item><title><![CDATA[Luogu P3067 [USACO12OPEN]Balanced Cow Subsets G]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/128719843</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/128719843</guid><author>SandwichBK</author><pubDate>Tue, 17 Jan 2023 19:34:16 +0800</pubDate><description><![CDATA[我们定义一个奶牛集合SSSABABA∪BSA∩B∅现在给定大小为n的奶牛集合S，询问它有多少个子集是平衡的。请注意，奶牛之间是互不相同的，但是它们的产奶量可能出现相同。]]></description><category></category></item><item><title><![CDATA[Luogu P4799 [CEOI2015 Day2] 世界冰球锦标赛]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/128514351</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/128514351</guid><author>SandwichBK</author><pubDate>Sun, 01 Jan 2023 18:44:05 +0800</pubDate><description><![CDATA[给出 Bobek 的预算和每场比赛的票价，试求：如果总票价不超过预算，他有多少种观赛方案。如果存在以其中一种方案观看某场比赛而另一种方案不观看，则认为这两种方案不同。]]></description><category></category></item><item><title><![CDATA[HDU3085 Nightmare Ⅱ]]></title><link>https://blog.youkuaiyun.com/SandwichBK/article/details/128512656</link><guid>https://blog.youkuaiyun.com/SandwichBK/article/details/128512656</guid><author>SandwichBK</author><pubDate>Sun, 01 Jan 2023 15:24:48 +0800</pubDate><description><![CDATA[幽灵的走与人的走是不同的。幽灵向外分身，即触碰范围增大，即只要它与人的曼哈顿距离足够近，人就会死。人行走的路线（方案）是不一定的，不同的路线是不同的状态，求两个人从两头走的最短步数，相遇的那一时刻是能到达的点有重合的时候，双向宽搜。因为鬼先走了，所以先判断目前位置能不能被抓到，然后走，走到的位置也不能被抓到。关于鬼，只需保证人到它的曼哈顿距离够长，不需要给它做实际的操作，否则太麻烦了。在每一秒内：幽灵的触碰范围+2，二日月走三步，女朋友走一步。与二日月相遇的实际上是过去的女朋友？女朋友扩展1层，同理。]]></description><category></category></item></channel></rss>