首先我们能注意到两个数x, y (0 < x , y < m) 乘以倍数互相可达当且仅当gcd(x, m) == gcd(y, m) 然后我们可以发现我们让gcd(x, m)从1开始出发走向它的倍数一个一个往里加元素就好啦, 往那边走 这个可以用dp求出来, dp[ i ] 表示 gcd(x, m)从 i 开始最大元素一共有多少个, dp[ i ] = max( dp[ j ] ) + cnt[ i ] 且 i | j 然后用扩展欧几里德求出走到下一步需要乘多少. #include<…
题面: You are given an array a with n distinct integers. Construct an array b by permuting a such that for every non-empty subset of indices S = {x1, x2, ..., xk} (1 ≤ xi ≤ n, 0 < k < n) the sums of elements on that positions in a and b are different,…
A. Alyona and mex 题目连接: http://codeforces.com/contest/739/problem/A Description Alyona's mother wants to present an array of n non-negative integers to Alyona. The array should be special. Alyona is a capricious girl so after she gets the array, she…
K. Perpetuum Mobile Time Limit: 2 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/gym/100187/problem/K Description The world famous scientist Innokentiy almost finished the creation of perpetuum mobile. Its main part is the energy generator which…
D. Optimal Number Permutation 题目连接: http://www.codeforces.com/contest/622/problem/D Description You have array a that contains all integers from 1 to n twice. You can arbitrary permute any numbers in a. Let number i be in positions xi, yi (xi < yi) i…
C. K-special Tables 题目连接: http://www.codeforces.com/contest/625/problem/C Description People do many crazy things to stand out in a crowd. Some of them dance, some learn by heart rules of Russian language, some try to become an outstanding competitiv…
D. The table 题目连接: http://www.codeforces.com/contest/226/problem/D Description Harry Potter has a difficult homework. Given a rectangular table, consisting of n × m cells. Each cell of the table contains the integer. Harry knows how to use two spells…
C. Harmony Analysis 题目连接: http://www.codeforces.com/contest/610/problem/C Description The semester is already ending, so Danil made an effort and decided to visit a lesson on harmony analysis to know how does the professor look like, at least. Danil…
D. Lazy Student Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/606/problem/D Description Student Vladislav came to his programming exam completely unprepared as usual. He got a question about some strange algorithm on a gr…
E. Brackets in Implications Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/550/problem/E Description Implication is a function of two logical arguments, its value is false if and only if the value of the first argument is…
D. Regular Bridge Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/550/problem/D Description An undirected graph is called k-regular, if the degrees of all its vertices are equal k. An edge of a connected graph is called a b…
C. The Closest Pair Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/312/problem/C Description Currently Tiny is learning Computational Geometry. When trying to solve a problem called "The Closest Pair Of Points In The Plane…
Problem H. Hard TestTime Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/gym/100342/attachments Description Andrew is having a hard time preparing his 239-th contest for Petrozavodsk. This time the solution to the problem is based on Di…
A. 24 Game Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/468/problem/A Description Little X used to play a card game called "24 Game", but recently he has found it too easy. So he invented a new game. Initially you ha…
A. Combination Lock time limit per test:2 seconds memory limit per test:256 megabytes input:standard input output:standard output Scrooge McDuck keeps his most treasured savings in a home safe with a combination lock. Each time he wants to put there…
