求好串个数刚好为n个,且好串长度最大不超过k的01串数量。 子串的定义:去掉若干头部元素(可以为0个),去掉若干尾部元素(可以为0个),剩余的字符串。 10110 举例,对于上述字符串,它的好串个数为6个,分别为 1,10, 01,1 1,10 数据范围 1<=k<=n<=2500 思路 对于一个01串,我们观察它的好串个数。设m为01
具体来说,可以类似杜教筛地预处理前O(n2/3)O(n2/3)的点值,然后后面的递归下去算,平衡一下块大小就能过。 #include<cstdio>#include<cstring>#include<cmath>#include<vector>#include<unordered_map>#include<algorithm>typedeflonglongll;constll mod =998244353;constintmaxn =1E+6+5;intT, n, m, N, ...
E. Counting Binary Strings(排列组合、dp) 题意: 对于一个只含有0和1的字符串s,如果它的子串\hat{s}只含有1个1,我们就称他为好子串。 现在我们希望知道,有多少个字符串s满足以下要求: s有且仅有n个好子串; s的好子串的长度均不超过k。 答案可能很大,需要对998244353取模。另外,在考虑子串时,我们需要考...
题解2021年ICPC昆明赛区E.CountingBinaryTrees 考虑记根节点标号恰为n的⽅案数为f(n)，要求的就是 F(n)= n ∑i=1f(i)⽽题⽬的条件相当于f=f⊗f+p，其中p(n)=[∃k i∣n]。注意到f(1)=0，于是这确实是良定义的。然后把前缀和拆⼀下，就有 F(n)=P(n)+ n ∑ i=1(f⊗f)(i)...
题解2021 年 ICPC 昆明赛区 E. Counting Binary Trees,题目链接考虑记根节点标号恰为\(n\)的方案数为\(f(n)\),要求的就是\[\begin{aligned}F(n)&=\sum_{i=1}^nf(i)\end{aligned}\]而题目的条件相当于\(f=f\otimesf+p\),其中\(p(n)=[\exists...
E Counting Binary Strings 链接:E- Counting Binary Strings 题意 如果二进制字符串 的子串 帮助帕特里克计算二进制字符串 ,使得 包含恰好 个好子串,并且没有长度严格大于 的好子串。注意,子串是根据它们在字符串中的位置来区分的,因此如果 如果从 中删除开头的几个(可能是零个或全部)字符和结尾的几个(可能是零...
SimPlate Coliform & E. coli (CEc) Multi-Dose Fill, 500 test Safety Information Certificate of AnalysisCertificate of OriginMore Documents Questions Be the first to ask a question Reviews ★★★No rating valueBe the first to write a review. This action will open a modal dialog. 1 star...
Lowest Common Ancestor of a Binary Search Tree, Lowest Common Ancestor of a Binary Tree, Binary Tree Paths, Add Digits, Ugly Number, Longest Increasing Subsequence, Range Sum Query - Immutable, Range Sum Query 2D - Immutable, Additive Number, Power of Three, Counting Bits, Data Stream as Dis...
In C, conversions between decimal strings and binary floating point values are always rounded correctly in accordance with IEEE 754: the converted result is the number representable in the result's format that is nearest to the original value in the direction specified by the current rounding mode...
You can build a 32 bit Redis binary using: % make 32bit After building Redis, it is a good idea to test it using: % make test If TLS is built, running the tests with TLS enabled (you will need tcl-tls installed): % ./utils/gen-test-certs.sh % ./runtest --tls Fixing bu...