33.对于统计答案幂次的技巧 对于$x^k$,考虑其组合意义:将$k$个不同球放到$x$个不同的盒子里的方案数,直接维护不好维护,那么考虑枚举把这些球放到了哪些盒子里,最后乘上第二类斯特林数和对于的阶乘(保证盒子有序),可以利用一个dp来统计,每次转移的时候考虑是否选择这个盒子$x$ 然后这个做法相当于维护了答案的下降幂,由于下降幂优秀的性质 $(x+1)^{\underline{m}}= x^{\underline{m}}+mx^{\underline{m-1}}$ 最后利用第二类斯特林数将下…

1.树上拓扑排序计数 结论$\dfrac{n!}{\prod\limits_{i=1}^n size_i}$ 对于节点$i$,其子树随意排序的结果是$size[i]!$ 但$i$需要排在第一位,只有$size[i]-1$个数可以任意排 乘上$\frac{1}{size[i]}$ 2.DAG上的问题退化成有向树解决 如果转化为DAG问题的题目,如果边与边之间有传递关系 可以退化成树进行解决 在建树的时候需要关心的是某一个点的直接父亲是什么 如ATcoder的ABC158F 3.在基环树上DP 主要…

This blog contains some ideas and tricks about USB hacking.…

作者:zhbzz2007 出处:http://www.cnblogs.com/zhbzz2007 欢迎转载,也请保留这段声明.谢谢! 本文翻译自 RECURRENT NEURAL NETWORKS TUTORIAL, PART 2 – IMPLEMENTING A RNN WITH PYTHON, NUMPY AND THEANO . github地址 在这篇博文中,我们将会使用Python从头开始实现一个循环神经网络,并且利用Theano(一个在GPU上执行操作的库)优化原始的实现.所有的代码…

We recommend collecting test ideas continuously from a variety of information sources. Consider the following, and think about values, risks, opportunities; find shortcuts to cover what is important.1. Capabilities. The first and obvious test ideas d…

I passionately enjoy working with commands as they offer more control over a Linux system than GUIs(Graphical User Interfaces) applications, therefore am always on the look out to discover or figure out interesting ways and ideas to make Linux so eas…

Table of Contents Practical Process Control Proven Methods and Best Practices for Automatic PID Control I. Modern Control is Based on Process Dynamic Behavior (by Doug Cooper) 1) Fundamental Principles of Process Control Motivation and Terminology of…

Blog Ideas How-to Post Case Studies Product + Service Updates Product Reviews Content Survey Current Trends Video Tutorials Event or Trade Show Recap Pro and Con Lists Myths in the IT Industry Customer Testimonials Common Mistakes Blog Round-Up Curre…

题目链接:Path Sum II | LeetCode OJ Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. For example: Given the below binary tree and sum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ / \ 7 2 5 1 return [ [5,4,11,2],…

题目链接:Populating Next Right Pointers in Each Node II | LeetCode OJ Follow up for problem "Populating Next Right Pointers in Each Node". What if the given tree could be any binary tree? Would your previous solution still work? Note: You may only u…