转自别人的博客.这里记录一下 这题是定义如下的一个数: S(0, 0) = 1; S(n, 0) = 0 for n > 0;S(0, m) = 0 for m > 0; S(n, m) = m S(n - 1, m) + S(n - 1, m - 1), for n, m > 0. 也就是题中所说的把一个含有n个元素的集合分成m份,共有多少种分法. 现在题目就是要求S(n, m)的奇偶性. 如果m是一个偶数的话,那么我们可以推出 S(n, m) Ξ S(n-1, m-1) (mod 2…

Binary Stirling Numbers Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 1761   Accepted: 671 Description The Stirling number of the second kind S(n, m) stands for the number of ways to partition a set of n things into m nonempty subsets.…

@(POJ)[Stirling數, 排列組合, 數形結合] Description The Stirling number of the second kind S(n, m) stands for the number of ways to partition a set of n things into m nonempty subsets. For example, there are seven ways to split a four-element set into two part…

题目链接 http://poj.org/problem?id=1430 题解 qaq写了道水题-- 在模\(2\)意义下重写一下第二类Stirling数的递推式: \[S(n,m)=S(n-1,m-1)+(S(n-1,m)\ \text{and}\ m)\] 令\(S'(n,m)=S(n+m,m)\), 那么递推式变成了\(S'(n,m)=S'(n,m-1)+(S'(n-1,m)\ \text{and}\ m)\) 也就相当于从\((0,0)\)走到\((n,m)\)的NE Lattice Pa…

传送门 题意: 求\(S(n,m)\% 2\)的值,\(n,m\leq 10^9\),其中\(S(n,m)\)是指第二类斯特林数. 思路: 因为只需要关注奇偶性,所以递推式可以写为: 若\(m\)为偶数,\(S(n,m)=S(n-1,m-1)\); 若\(m\)为奇数,\(S(n,m)=S(n-1,m-1)+S(n-1,m)\). 观察第二个式子,和组合数的递推公式一模一样.所以我们可以联想到组合数. 将上述递推式子前面几项的值写出来,会发现偶数列错了前面奇数列一列,若只看奇数列,则为杨辉三角的…

http://poj.org/problem?id=1430 题目: 求 第二类 斯特林数 的 奇偶性  即 求 s2 ( n , m ) % 2 : 题解: https://blog.csdn.net/ez_2016gdgzoi471/article/details/80219736 #include<cstdio> #include<cstdlib> #include<cstring> #include<cmath> #include<iostre…

题目链接: http://acm.hust.edu.cn/vjudge/problem/48421 Binary Tree Time Limit: 3000MS 问题描述 Binary Tree is a tree data structure where each node has at most two children, usually they are distinguished as left and right child. And the node having the child…

今天继续攒人品...真开心啊O(∩_∩)O~~各种身体不舒服~~ https://icpcarchive.ecs.baylor.edu/external/65/6577.pdf 题意是这样的,现在有一个向下无限延伸的二叉树.然后输入起点(通过只含LRU的字符串S,从根结点开始执行).LRU分别表示往左儿子走,往右儿子走,往爹娘处走(根结点的爹娘是自己,估计他是石头里蹦出来的). 然后输入一个可选步骤串T.可以选择T中的子序,从起点开始走.然后问可以走到多少个不同的结点. 比赛的时候不会做啊╮(╯…

题目大意 求子集斯特林数\(\left\{\begin{matrix}n\\m\end{matrix}\right\}\%2\) 方法1 数形结合 推荐一篇超棒的博客by Sdchr 就是根据斯特林的递推式,分奇偶讨论 得到一个函数\(P_{n,m}\equiv\left\{\begin{matrix}n\\m\end{matrix}\right\}\% 2\) 再根据函数递推式通过画图,数形结合 转化成图中从一点走到另一点的方案数 变成组合问题求解 做法 这是给连插板都不会的我看的 \(a_1…

这个东西先放在这吧.做过的以后会用#号标示出来 1.burnside定理,polya计数法    这个大家可以看brudildi的<组合数学>,那本书的这一章写的很详细也很容易理解.最好能完全看懂了,理解了再去做题,不要只记个公式.    *简单题:(直接用套公式就可以了)    pku2409 Let it Bead      #http://acm.pku.edu.cn/JudgeOnline/problem?id=2409    pku2154 Color   #http://acm.p…

转自:http://blog.sina.com.cn/s/blog_6635898a0100magq.html 1.burnside定理,polya计数法 这个大家可以看brudildi的<组合数学>,那本书的这一章写的很详细也很容易理解.最好能完全看懂了,理解了再去做题,不要只记个公式. *简单题:(直接用套公式就可以了) pku2409 Let it Bead      http://acm.pku.edu.cn/JudgeOnline/problem?id=2409 pku2154 Co…

 1.burnside定理,polya计数法 这个专题我单独写了个小结,大家可以简单参考一下:polya 计数法,burnside定理小结 2.置换,置换的运算 置换的概念还是比较好理解的,<组合数学>里面有讲.对于置换的幂运算大家可以参考一下潘震皓的那篇<置换群快速幂运算研究与探讨>,写的很好. *简单题:(应该理解概念就可以了) pku3270 Cow Sorting http://acm.pku.edu.cn/JudgeOnline/problem?id=3270 pku…

在盛情收到学弟邀请给他们整理ACM数学方面的知识体系,作为学长非常认真的弄了好久,希望各学弟不辜负学长厚爱!!!非常抱歉因为电脑全盘格式化好多word.PPT都丢失,我尽量具体地给大家找到各知识点学习链接及题目链接,敬请原谅.里面非常多牛人写的博客,我都贴了网址,大家认真看下吧! 本人数论博客地址: http://blog.csdn.net/xh_reventon/article/category/1334125 一.组合数学: 1.  Polya定理.burnside定理 http://blo…

You are given two huge binary integer numbers aa and bb of lengths nn and mmrespectively. You will repeat the following process: if b>0b>0, then add to the answer the value a & ba & b and divide bb by 22 rounding down (i.e. remove the last d…

备份文件时看到的.我以前居然下过这东西. 2016-12-4 12:05:52更新 纯文本格式真棒.假如使用word写的我能拷过来格式还不乱?? Markdown真好. Bit Hacks By Sean Eron Anderson seander@cs.stanford.edu Converted to Markdown by Joe Gibson (@gibsjose) joseph.gibson@nasa.gov Edits and Table of Contents by Jeroen…

直接抄: https://apollomapping.com/2012/August/article15.html For this month’s Geospatial Frequently Asked Question (G-FAQ), I pivot to a topic that deserves more attention than it gets, and that is bit depth. Some of you may have heard this term when or…

http://graphics.stanford.edu/~seander/bithacks.html Bit Twiddling Hacks By Sean Eron Andersonseander@cs.stanford.edu Individually, the code snippets here are in the public domain (unless otherwise noted) — feel free to use them however you please. Th…

原地址: Home / Database / Oracle Database Online Documentation 11g Release 2 (11.2) / Database Administration Data Types Each value manipulated by Oracle Database has a data type. The data type of a value associates a fixed set of properties with the va…

一.插值 1.文本 数据绑定最常见的形式是使用双大括号({{  }}--"Mustache"语法)的文本插值 <div class="mustache"> <span>小红:{{ juice }}</span> <span v-once>不变的选择:{{ juice1 }}</span> </div> juice: '奇异果', juice1: '百香果'  2.原始HTML:双大括号会将数据解…

原文地址 Floating point numbers — Sand or dirt Floating point numbers are like piles of sand; every time you move them around, you lose a little sand and pick up a little dirt. — Brian Kernighan and P.J. Plauger Real numbers are a very important part of…

Poisson Distribution Given a Poisson process, the probability of obtaining exactly successes in trials is given by the limit of a binomial distribution (1) Viewing the distribution as a function of the expected number of successes (2) instead of the…

要back的题目 目标是全绿!back一题删一题! acmm7 1003 1004 acmm8 1003 1004 sysu20181013 Stat Origin Title Solved A Gym 100624A Kingdoms   B Gym 100624B Who wants to live forever? Solved C Gym 100624C Chemist's vows   D Gym 100624D Non-boring sequences Attempted E Gym…

Sheldon Numbers 题目链接: http://acm.hust.edu.cn/vjudge/contest/127406#problem/H Description According to Sheldon Cooper, the best number is 73. In his own words, "The best number is 73. 73 is the 21st prime number. Its mirror, 37, is the 12th, and its m…

http://acm.hdu.edu.cn/showproblem.php?pid=1390 Binary Numbers Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 2298    Accepted Submission(s): 1460 Problem Description Given a positive integer n…

Binary Numbers 点我 Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 3820    Accepted Submission(s): 2321 Problem Description Given a positive integer n, find the positions of all 1's in its binary…

Given a binary tree, each node has value 0 or 1.  Each root-to-leaf path represents a binary number starting with the most significant bit.  For example, if the path is 0 -> 1 -> 1 -> 0 -> 1, then this could represent 01101 in binary, which is…

E. Binary Numbers AND Sum 题目链接:https://codeforces.com/contest/1066/problem/E 题意: 给出两个用二进制表示的数,然后将第二个二进制不断地往右边移一位,每次答案加上这两个的交集,求最后的答案. 题解: 考虑第二个二进制每一位对答案的贡献就行了,然后对第一个二进制算前缀和就ok了. 代码如下: #include <bits/stdc++.h> using namespace std; typedef long long l…

Binary Numbers Time Limit: 2 Seconds      Memory Limit: 65536 KB Given a positive integer n, print out the positions of all 1's in its binary representation. The position of the least significant bit is 0. Example The positions of 1's in the binary r…

problem 1022. Sum of Root To Leaf Binary Numbers 参考 1. Leetcode_easy_1022. Sum of Root To Leaf Binary Numbers; 完…

1022. 从根到叶的二进制数之和 1022. Sum of Root To Leaf Binary Numbers 题目描述 Given a binary tree, each node has value 0 or 1. Each root-to-leaf path represents a binary number starting with the most significant bit. For example, if the path is 0 -> 1 -> 1 ->…