[HDU4135]Co-prime 题意 给出三个整数N,A,B.问在区间[A,B]内,与N互质的数的个数.其中N<=10^9,A,B<=10^15. 分析 容斥定理的模板题.可以通过容斥定理求出[1,n]与x互质的数的个数.方法是先将x进行质因子分解,然后对于每个质因子pi,[1,n]内可以被pi整除的数目为n/pi.可以通过容斥定理解决逆命题,既[1,n]与x不互质的数目.n/p1+n/p2+n/p3-n/p1p2-n/p1p3-n/p2p3+n/p1p2p3.既奇数是加,偶数是减.具体的…

When ?? was born, seven crows flew in and stopped beside him. In its childhood, ?? had been unfortunately fall into the sea. While it was dying, seven dolphins arched its body and sent it back to the shore. It is said that ?? used to surrounded by 7…

How many integers can you find Time Limit: 12000/5000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 3315    Accepted Submission(s): 937 Problem Description   Now you get a number N, and a M-integers set, you shoul…

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…

题目连接:hdu_5213_Lucky 题意:给你n个数,一个K,m个询问,每个询问有l1,r1,l2,r2两个区间,让你选取两个数x,y,x,y的位置为xi,yi,满足l1<=xi<=r1,l2<=y2<=r2,使得x+y=K: 题解:首先,这题没有修改操作,即可以离线,离线区间问题就要想到莫队算法,然后看状态怎么搞,因为要求的答案满足区间的可加性,我们令f(l,r)表示 l到r这个区间满足条件的ans,令F(l1,r1,l2,r2)为在这两个区间内选取的数满足条件的ans,则根…

题目链接:http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=3556 How Many Sets I Time Limit: 2 Seconds      Memory Limit: 65536 KB Give a set S, |S| = n, then how many ordered set group (S1, S2, ..., Sk) satisfies S1 ∩ S2 ∩ ... ∩ Sk = ∅. (Si is…

题意:给定区间和n,求区间中与n互素的数的个数, . 思路:利用容斥定理求得先求得区间与n互素的数的个数,设表示区间中与n互素的数的个数, 那么区间中与n互素的数的个数等于.详细分析见求指定区间内与n互素的数的个数 容斥原理 AC代码 #include <cstdio> #include <cmath> #include <cctype> #include <bitset> #include <algorithm> #include <cs…

2301: [HAOI2011]Problem b Time Limit: 50 Sec  Memory Limit: 256 MB Submit: 7732  Solved: 3750 [Submit][Status][Discuss] Description 对于给出的n个询问,每次求有多少个数对(x,y),满足a≤x≤b,c≤y≤d,且gcd(x,y) = k,gcd(x,y)函数为x和y的最大公约数. 100%的数据满足:1≤n≤50000,1≤a≤b≤50000,1≤c≤d≤50000…

题目 一个有 \(N\) 个 元素的集合有 \(2^N\) 个不同子集(包含空集), 现在要在这 \(2^N\) 个集合中取出若干集合(至少一个), 使得它们的交集的元素个数为 \(K\) ,求取法的方案数,答案模 \(1000000007\) . \((1 \le N \le 10^6, 0 \le K \le N)\) 题解 又是一道 裸的 广义容斥定理 还没这道题难qwq 广义容斥定理 (二项式反演) : \[\displaystyle b_k = \sum_{i=k}^n \binom…

GCD Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 4141    Accepted Submission(s): 1441 Problem Description Given 5 integers: a, b, c, d, k, you're to find x in a...b, y in c...d that GCD(x, y)…