随笔分类 - ACM-数论
摘要：Chinese people think of '8' as the lucky digit. Bob also likes digit '8'. Moreover, Bob has his own lucky number L. Now he wants to construct his luck
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摘要：1303: [CQOI2009]中位数图 Description 给出1~n的一个排列，统计该排列有多少个长度为奇数的连续子序列的中位数是b。中位数是指把所有元素从小到大排列后，位于中间的数。 Input 第一行为两个正整数n和b ，第二行为1~n 的排列。 Output 输出一个整数，即中位数为b
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摘要：1192: [HNOI2006]鬼谷子的钱袋 Description 鬼谷子非常聪明，正因为这样，他非常繁忙，经常有各诸侯车的特派员前来向他咨询时政。有一天，他在咸阳游历的时候，朋友告诉他在咸阳最大的拍卖行（聚宝商行）将要举行一场拍卖会，其中有一件宝物引起了他极大的兴趣，那就是无字天书。但是，他的行
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摘要：3085: 反质数加强版SAPGAP Description 先解释一下SAPGAP=Super AntiPrime, Greatest AntiPrime（真不是网络流），于是你就应该知道本题是一个关于反质数（Antiprime）的问题。下面给出反质数的定义： 将一个正整数i的约数个数记为g(i)
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摘要：1053: [HAOI2007]反素数ant Description 对于任何正整数x，其约数的个数记作g(x)。例如g(1)=1、g(6)=4。如果某个正整数x满足：g(x)>g(i) 0<i<x ，则称x为反质数。例如，整数1，2，4，6等都是反质数。现在给定一个数N，你能求出不超过N的最大的反
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摘要：Given an array of integers , we say a set is a prime set of the given array, if and is prime. BaoBao has just found an array of integers in his pocket
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摘要：DreamGrid has a nonnegative integer . He would like to divide into nonnegative integers and minimizes their bitwise or (i.e. and should be as small as
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摘要：Little boxes on the hillside. Little boxes made of ticky-tacky. Little boxes. Little boxes. Little boxes all the same. There are a green boxes, and b
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摘要：A triangle is a Heron’s triangle if it satisfies that the side lengths of it are consecutive integers t−1, t, t+ 1 and thatits area is an intege
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摘要：Jessie and Justin want to participate in e-sports. E-sports contain many games, but they don't know which one to choose, so they use a way to make dec
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摘要：There are NN children in kindergarten. Miss Li bought them NN candies. To make the process more interesting, Miss Li comes up with the rule: All the c
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摘要：Now you get a number N, and a M-integers set, you should find out how many integers which are small than N, that they can divided exactly by any integ
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摘要：Every year there is the same problem at Halloween: Each neighbour is only willing to give a certain total number of sweets on that day, no matter how
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摘要：You are in a cave, a long cave! The cave can be represented by a 1 x N grid. Each cell of the cave can contain any amount of gold. Initially you are i
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摘要：You are in a maze; seeing n doors in front of you in beginning. You can choose any door you like. The probability for choosing a door is equal for all
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摘要：一：N条直线分割平面 假设，x条线能将平面分为f(x)份，这对于份f(n) 第n条线，和其他n-1条线都有交点时，增加量最大，为n; 则： f(n)=f(n-1)+n; 有f(0)=1；得到：n 条直线分割平面的数量最大为：f(n)=n*(n+1)/2 + 1; 二. “V” 形线分割平面 对于“V
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摘要：Little Q and Little T are playing a game on a tree. There are n vertices on the tree, labeled by 1,2,...,n , connected by n−1 bidirectional edges. The
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摘要：链接：http://acm.hdu.edu.cn/showproblem.php?pid=6322 Problem Description In number theory, Euler's totient function φ(n) counts the positive integers up
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摘要：Given an integer nn, Chiaki would like to find three positive integers xx, yy and zzsuch that: n=x+y+zn=x+y+z, x∣nx∣n, y∣ny∣n, z∣nz∣n ...
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摘要：LsF is visiting a local amusement park with his friends, and a mirror room successfully attracts his attention. Inside the mirror room...
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