To confuse the opponents, the Galactic Empire represents fractions in an unusual format. The fractions are represented as two sets of integers. The product of numbers from the first set gives the fraction numerator, the product of numbers from the se…

ACM思维题训练集合 To confuse the opponents, the Galactic Empire represents fractions in an unusual format. The fractions are represented as two sets of integers. The product of numbers from the first set gives the fraction numerator, the product of numbers…

题目大意: 给出两个集合,第一个集合数的乘积是分子,第二个集合的数的乘积是分母,要求够造一个同样的集合,但是得到的分数是最简分数. 分析: 寻找思路并不复杂,对两个集合的每个数进行质因数分解,然后统计整个集合的质因数分解情况,再将两个集合的质因数的次数大减小即可.构造时使两个集合中元素的个数不变,尽可能地构造成原先集合的数,如果不行就填一个 \(1\).但质因数分解的过程中不能采用 \(O(\sqrt n)\) 的复杂度,会超时,接下来介绍本题中进行质因数分解的方法. 其实也不是很复杂,就是对于…

题目地址: 选题为入门的Codeforce div2/div1的C题和D题. 题解: A:CF思维联系–CodeForces -214C (拓扑排序+思维+贪心) B:CF–思维练习-- CodeForces - 215C - Crosses(思维题) C:CF–思维练习–CodeForces - 216C - Hiring Staff (思维+模拟) D:CF思维联系–CodeForces-217C C. Formurosa(这题鸽了) E:CF思维联系–CodeForces - 218C E…

codeforces 627 D. Preorder Test 二分 + 树dp 做logn次树dp codeforces 578D.LCS Again 给出一个字符串str,长度n<=10^6,由m种字符组成,问有多少个长度为n,与str的LCS 为 n-1的字符串t 这道题可以用dp套dp,但是我不会阿 可以找规律统计,考虑: 1.取哪个位置 2.放在哪个位置 3.放什么字符 可以知道,如果str分成了block份,每一份的字符相同,则 ans = block * n * (m - 1) 但…

A. Shooshuns and Sequence 显然\([k,n]\)之间所有数均要相同,为了求最少步数,即最多模拟\(n\)次操作即可. B. Cosmic Tables 映射\(x_i,y_i\)即可. C. Reducing Fractions 分别统计\(\prod a_i.\prod b_i\)的质因子系数,然后取小即可. D. Olympiad 相当于计算\(a_i+b_j \ge x\)最大数量,显然每次从\(a_i\)获\(b_j\)中找最大值,然后从另一集合中找出最小值刚好…

Prime Number CodeForces - 359C Simon has a prime number x and an array of non-negative integers a1, a2, ..., an. Simon loves fractions very much. Today he wrote out number on a piece of paper. After Simon led all fractions to a common denominator and…

传送门 Description Vladik and Chloe decided to determine who of them is better at math. Vladik claimed that for any positive integer n he can represent fraction   as a sum of three distinct positive fractions in form . Help Vladik with that, i.e for a g…

D. On Sum of Fractions Let's assume that v(n) is the largest prime number, that does not exceed n; u(n) is the smallest prime number strictly greater than n. Find . Input The first line contains integer t (1 ≤ t ≤ 500) — the number of testscases. Eac…

别看本文没有几页纸,本着把经典的文多读几遍的想法,把它彩印出来看,没想到效果很好,比在屏幕上看着舒服.若用蓝色的笔圈出重点,这篇文章中几乎要全蓝.字字珠玑. Reducing the Dimensionality of Data with Neural Networks G.E. Hinton and R.R. Salakhutdinov  摘要 训练一个带有很小的中间层的多层神经网络,可以重构高维空间的输入向量,实现从高维数据到低维编码的效果.(原文为high-dimensional data…