题面 链接:CF548E Description Mike is a bartender at Rico's bar. At Rico's, they put beer glasses in a special shelf. There are n kinds of beer at Rico's numbered from 1 to n. i-th kind of beer has *a**i* milliliters of foam on it. Maxim is Mike's boss. T…

目录 Codeforces 547C/548E - Mike and Foam 题解 前置芝士 - 容斥原理 题意 想法(口胡) 做法 程序 感谢 Codeforces 547C/548E - Mike and Foam 题解 前置芝士 - 容斥原理 容斥原理是简单的小学奥数求多个集合的并集的算法,最基本的思想大概是如下内容: 这是一道简单例题:有\(10\)个学生喜欢唱歌,有\(15\)个学生喜欢跳舞,有\(5\)个学生两种活动都喜欢,没有不喜欢前述两种活动的学生,那么一共有多少个学生呢? 相…

hdu4135 求[L,R]范围内与N互质的数的个数. 分别求[1,L]和[1,R]和n互质的个数,求差. 利用容斥原理求解. 二进制枚举每一种质数的组合,奇加偶减. #include <bits/stdc++.h> using namespace std; typedef long long ll; ; int fac[N], cnt; void factor(int n) { cnt = ; int limit = sqrt(n); ; i <= limit; ++i) { ) fa…

B. Pasha and Phone Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/595/problem/B Description Pasha has recently bought a new phone jPager and started adding his friends' phone numbers there. Each phone number consists of ex…

E. Devu and Flowers 题目连接: http://codeforces.com/contest/451/problem/E Description Devu wants to decorate his garden with flowers. He has purchased n boxes, where the i-th box contains fi flowers. All flowers in a single box are of the same color (hen…

转载请注明出处: http://www.cnblogs.com/fraud/          ——by fraud D. Xenia and Dominoes Xenia likes puzzles very much. She is especially fond of the puzzles that consist of domino pieces. Look at the picture that shows one of such puzzles. A puzzle is a 3 ×…

B. Pasha and Phone   Pasha has recently bought a new phone jPager and started adding his friends' phone numbers there. Each phone number consists of exactly n digits. Also Pasha has a number k and two sequences of length n / k (n is divisible by k) a…

题意:给出数组arr和一个空数组dst.从arr中取出一个元素到dst为一次操作.问每次操作后dst数组中gcd等于1的组合数.由于数据都小于10^6,先将10^6以下的数分解质因数.具体来说从2开始,将2的倍数全部加2因子(用的vector),3的倍数加3因子.4不是质数,它的倍数不加因子. 还要一个cnt数组记录dst中有几个数是数组下标的倍数. 在放入元素x到dst数组,对于它的每个质因数及质因数间的乘积,看cnt中的量.组合数的增量为dst的sz(size)-(cnt[x的质因数])(即…

题目链接 \(Description\) 给定n个数(\(1\leq a_i\leq 5*10^5\)),每次从这n个数中选一个,如果当前集合中没有就加入集合,有就从集合中删去.每次操作后输出集合中互质的数对个数. \(Solution1\) 考虑暴力一点,对于要修改的数分解质因数,集合中与它互质的数的个数就是 n-(有1个公共质因数)+(有2个公共质因数)-... 维护一下每种因子(可以是多个因数的积)对应集合中的多少个数就行. 真的好暴力..但是一个数的质因子大多也就4.5个,so是没问题的…

D. Winter is here 题目连接: http://codeforces.com/contest/839/problem/D Description Winter is here at the North and the White Walkers are close. John Snow has an army consisting of n soldiers. While the rest of the world is fighting for the Iron Throne,…