[hdu5213]容斥原理+莫队算法

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[hdu5213]容斥原理+莫队算法

题意:给一个序列a,以及K,有Q个询问,每个询问四个数,L,R,U,V, 求L<=i<=R,U<=j<=V,a[i]+a[j]=K的(i, j)对数(题目保证了L <= R < U <= V). 思路:首先用容斥原理把询问变为i,j同区间,记f(A,B)为答案,'+'为区间的并,A=[L,R],B=[U,V],C=[u+1,v-1],则f(A,B) = f(A+B+C,A+B+C)+f(C,C)-f(A+C,A+C)-f(B+C,B+C).令g(L,R) = f(…

HDU5213(容斥定理+莫队算法）

传送门题意给出n个数和幸运数k,m次询问,每次询问[l1,r1]和[l2,r2]有多少对数满足x+y=k,x∈[l1,r1],y∈[l2,r2] 分析看到m只有3e4,可以考虑\(m\sqrt{n}\)的莫队算法,具体讲解.首先设f(l,r)表示从l到r满足x+y=k的对数,那么由容斥定理得到,\[f(l1,r1,l2,r2)=f(l1,r2)-f(l1,l2-1)-f(r1+1,r2)+f(r1+1,l2-1)\],那么就可以结合莫队算法离线求出询问结果,具体见代码 trick 代码 #…

NBUT 1457 莫队算法离散化

Sona Time Limit:5000MS Memory Limit:65535KB 64bit IO Format: Submit Status Practice NBUT 1457 Appoint description: Description Sona, Maven of the Strings. Of cause, she can play the zither. Sona can't speak but she can make fancy music. Her…

BZOJ 2038: [2009国家集训队]小Z的袜子(hose) [莫队算法]【学习笔记】

2038: [2009国家集训队]小Z的袜子(hose) Time Limit: 20 Sec Memory Limit: 259 MBSubmit: 7687 Solved: 3516[Submit][Status][Discuss] Description 作为一个生活散漫的人,小Z每天早上都要耗费很久从一堆五颜六色的袜子中找出一双来穿.终于有一天,小Z再也无法忍受这恼人的找袜子过程,于是他决定听天由命……具体来说,小Z把这N只袜子从1到N编号,然后从编号L到R(L 尽管小Z并不在意两只…

NPY and girls-HDU5145莫队算法

Time Limit: 8000/4000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Problem Description NPY's girlfriend blew him out!His honey doesn't love him any more!However, he has so many girlfriend candidates.Because there are too many girls and…

Codeforces617 E . XOR and Favorite Number(莫队算法)

XOR and Favorite Number time limit per test: 4 seconds memory limit per test: 256 megabytes input: standard input output: standard output Bob has a favorite number k and ai of length n. Now he asks you to answer m queries. Each query is given by a pa…

Bzoj 2038---[2009国家集训队]小Z的袜子(hose) 莫队算法

题目链接 http://www.lydsy.com/JudgeOnline/problem.php?id=2038 Description 作为一个生活散漫的人,小Z每天早上都要耗费很久从一堆五颜六色的袜子中找出一双来穿.终于有一天,小Z再也无法忍受这恼人的找袜子过程,于是他决定听天由命……具体来说,小Z把这N只袜子从1到N编号,然后从编号L到R(L 尽管小Z并不在意两只袜子是不是完整的一双,甚至不在意两只袜子是否一左一右,他却很在意袜子的颜色,毕竟穿两只不同色的袜子会很尴尬.你的任务便是告诉小…