题意很简单啦,求S(n,m)的值 通过打表我们可以知道 S(n + 1, m) = S(n, m) * 2 - C(n, m); S(n - 1, m) = (S(n, m) + C(n - 1, m)) / 2; 首先我们考虑杨辉三角和二项式定理,但是看了看数据情况,貌似时间不允许呢 这个时候就要祭出莫队算法啦,关于莫队算法呢,更详细的理解请看:2010国家集训队<小Z的袜子>命题报告 莫队算法是一种用于解决可离线的,求区间[L,R]问题的算法 这个题当然就可以离线去求啦,莫队算法在解决离线…

题目链接:传送门 思路: 考虑每一列有2种颜色,总共有n行,每一行的第一个格确定颜色,由于左右颜色不相同,后面的行就确定了. 所以总共有2^n中结果. 由于n太大,所以要用到费马小定理a^n%mod=a^(n%(mod-1))%mod,所以先求出a的指数,然后用快速幂求解就好了. #include<iostream> #include<cstdio> #include<cstring> #include<cmath> typedef long long LL…

HDU-6333 题意: 有n个不同的苹果,你最多可以拿m个,问有多少种取法,多组数据,组数和n,m都是1e5,所以打表也打不了. 思路: 这道题要用到组合数的性质,记S(n,m)为从n中最多取m个的方法总数,显然是C(n,0),C(n,1)……C(n,m)的和. 显然S(n,m+1) = S(n, m) + C(n,m+1); 还有一个等式就不那么明显了,S(n+1,m) = 2 * S(n,m) - C(n,m); 我也是在王神犇的指导下明白的. 既然知道了一组(n,m)是可以在很快的时间下…

Parentheses Matrix Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 728    Accepted Submission(s): 294Special Judge Problem Description A parentheses matrix is a matrix where every element is e…

题意是给了一种矩阵的生成方式 让你求两个左边之间的矩阵里面的数加起来的和(不是求矩阵的值) 没看标程之前硬撸写了160行 用了前缀和以后代码量缩短到原来的1/3 根据规律可以推导出这个矩阵是在不断重复一个2L*2L的矩阵 求值时,先求出原点到(x2,y2)的值,再减去原点到(x1-1,y2)和原点到(x2,y1-1)的值,再加上被重复减去的原点到(x1-1,y1-1)的值 Problem E. Matrix from Arrays Time Limit: 4000/2000 MS (Java/O…

Problem K. Expression in Memories Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 262144/262144 K (Java/Others)Total Submission(s): 0    Accepted Submission(s): 0Special Judge Problem Description Kazari remembered that she had an expression s…

就是画个图啦 分三个平面去画orz #include <iostream> #include <cmath> #include <cstring> #include <algorithm> using namespace std; ][]; int main() { ios::sync_with_stdio(false); int t; cin >> t; while (t--) { ; i < ; i++) ; j < ; j++)…

本题题意是,给你一个长度为n的序列,使用最少的操作把序列转换为从小到大的顺序,并输出操作数*min(x,y) 实质上是算出该序列中有多少逆序对,有归并排序和树状数组两种算法,由于数据之间的差值有点大,所以使用树状数组时需要先离散化 离散化后排序有两种方式,一种是先按value排,再按id排,另一种是按value排后,把重复的统一化 这里采用第一种方式 Swaps and Inversions Time Limit: 2000/1000 MS (Java/Others)    Memory Lim…

这个题的题意是给你n个字符串,认定()是一种平衡的串,两个以上连续的()()也是一种平衡的串,如果一对括号里面包含一个平衡的串,这个括号也被算在这个平衡的串之内, 如(()(()))是一个长度为8的平衡字符串,让你通过对给的n个串进行排序,组成一个新的串,问其中平衡串的最大长度是多少 这个题的重点是在对这些串排序规则的制定(本鶸连要排序都想不到) 如果要得到一个最长平衡串的串 需要遵循以下几点规则 注:左为'(',右为')' 1.左多右少的串在右多左少的左边 2.左少右多和左少右多排序时,左括号…

题意大致是给你一个整数n,让你确定是否有三个正整数x,y,z既能被n整除,又能x+y+z=n,并使xyz最大 从中根据规律可以看出,只有被3或被4整除的数才能满足题目要求 被3整除的最大值为n^3/3^3 被4整除的最大值为n^3/(2*4*4) Problem Description Given an integer n, Chiaki would like to find three positive integers x, y and z such that: n=x+y+z, x∣n, …

题意是一个长度为n的序列,给你m组区间(l,r),在这个区间里不能填入重复的数字,同时使整个序列字典序最小 同学用的优先队列,标程里使用的是贪心同时使用set维护答案序列 贪心是先采用pre数组来确定哪些区间不能重复,再通过记录从set弹出答案的位置来计算的 Problem Description Chiaki has an array of n positive integers. You are told some facts about the array: for every two e…

题目大意就是给你UTC-8时区的时间 让你求对应时区的时间 哇 这个题 看似简单,但是一开始怎么都过不了啊 同学用自己写的read过了,后来看了一下各位大佬说改成分钟随便过,就随便过了 Problem Description Chiaki often participates in international competitive programming contests. The time zone becomes a big problem.Given a time in Beijing…

题意是给3n个点,其中不可能存在任意三点共线的情况,让你在其中建n个三角形,点不能重复使用,三角形不能相互覆盖 做法是给每个点排序,按照先y轴排,再x轴排的顺序,三个三个一组从下往上输出,有人说是凸包,其实没那么麻烦 Problem Description Chiaki has 3n points p1,p2,…,p3n. It is guaranteed that no three points are collinear.Chiaki would like to construct n di…

A Boring Question Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 156    Accepted Submission(s): 72 Problem Description       Input   The first line of the input contains the only integer T,(1≤T…

题目链接 题意 : m张牌,可以翻n次,每次翻xi张牌,问最后能得到多少种形态. 思路 :0定义为反面,1定义为正面,(一开始都是反), 对于每次翻牌操作,我们定义两个边界lb,rb,代表每次中1最少时最少的个数,rb代表1最多时的个数.一张牌翻两次和两张牌翻一次 得到的奇偶性相同,所以结果中lb和最多的rb的奇偶性相同.如果找到了lb和rb,那么,介于这两个数之间且与这两个数奇偶性相同的数均可取到,然后在这个区间内求组合数相加(若lb=3,rb=7,则3,5,7这些情况都能取到,也就是说最后的…

2016暑假多校联合---Rikka with Sequence (线段树) Problem Description As we know, Rikka is poor at math. Yuta is worrying about this situation, so he gives Rikka some math tasks to practice. There is one of them: Yuta has an array A with n numbers. Then he make…

2016暑假多校联合---Windows 10(HDU:5802) Problem Description Long long ago, there was an old monk living on the top of a mountain. Recently, our old monk found the operating system of his computer was updating to windows 10 automatically and he even can't j…

2016暑假多校联合---Substring Problem Description ?? is practicing his program skill, and now he is given a string, he has to calculate the total number of its distinct substrings. But ?? thinks that is too easy, he wants to make this problem more interesti…

2016暑假多校联合---To My Girlfriend Problem Description Dear Guo I never forget the moment I met with you.You carefully asked me: "I have a very difficult problem. Can you teach me?".I replied with a smile, "of course"."I have n items,…

2016暑假多校联合---A Simple Chess   Problem Description There is a n×m board, a chess want to go to the position (n,m) from the position (1,1).The chess is able to go to position (x2,y2) from the position (x1,y1), only and if only x1,y1,x2,y2 is satisfied…

2016暑假多校联合---World is Exploding Problem Description Given a sequence A with length n,count how many quadruple (a,b,c,d) satisfies: a≠b≠c≠d,1≤a<b≤n,1≤c<d≤n,Aa<Ab,Ac>Ad.   Input The input consists of multiple test cases. Each test case begin wit…

2016暑假多校联合---Another Meaning Problem Description As is known to all, in many cases, a word has two meanings. Such as “hehe”, which not only means “hehe”, but also means “excuse me”. Today, ?? is chating with MeiZi online, MeiZi sends a sentence A to…

题目链接 Problem Description The Death Star, known officially as the DS-1 Orbital Battle Station, also known as the Death Star I, the First Death Star, Project Stardust internally, and simply the Ultimate Weapon in early development stages, was a moon-si…

题目链接 Problem Description HazelFan wants to build a rooted tree. The tree has n nodes labeled 0 to n−1, and the father of the node labeled i is the node labeled ⌊i−1k⌋. HazelFan wonders the size of every subtree, and you just need to tell him the XOR…

题目链接 Problem Description The center coordinate of the circle C is O, the coordinate of O is (0,0) , and the radius is r. P and Q are two points not outside the circle, and PO = QO. You need to find a point D on the circle, which makes PD+QD minimum.…

题目链接 Problem Description Talented Mr.Tang has n strings consisting of only lower case characters. He wants to charge them with Balala Power (he could change each character ranged from a to z into each number ranged from 0 to 25, but each two differen…

Is Derek lying? Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 612    Accepted Submission(s): 353 Problem Description Derek and Alfia are good friends.Derek is Chinese,and Alfia is Austrian.Thi…

暑假颓废了好久啊...重新开始写博客 题目大意:给定10w个数,10w个询问.每次询问一个区间[l,r],求出gcd(a[l],a[l+1],...,a[r])以及有多少个区间[l',r']满足gcd(a[l'],a[l'+1],...,a[r'])==gcd(a[l],a[l+1],...,a[r]). 第一问就是简单的ST表了,f[i,j]表示i~i+2^j-1的gcd是多少,预处理出来就可以O(1)查询了. 第二问需要分析一下.首先,对于任意一个左端点,显然随着右端点的右移,这个区间的gc…

题面传送门 一道非常不错的 FWT+插值的题 %%%%%%%%%%%% 还是那句话,反正非六校的看不到题对吧((( 方便起见在下文中设 \(n=2^d\). 首先很明显的一点是这题涉及两个维度:异或和与选出的元素的个数.因此考虑像子集卷积那样建立一个二元生成函数表示这个东西,具体来说我们定义一个幂级数 \(F\)​​ 形如 \(\sum\limits_{n\ge 0}\sum\limits_{m\ge 0}f_{n,m}x^ny^m\)​​,并定义两个幂级数 \(F,G\)​​ 的乘法得到的幂级…

由于 NFLSOJ 题面上啥也没有就把题意贴这儿了( 没事儿,反正是上赛季的题,你们非六校学生看了就看了,况且看了你们也没地方交就是了 题意: 给你一张 \(n\) 个点 \(m\) 条边的图 \(G=(V,E)\). 要求有多少张子图 \(G'=(V',E')\)​ 满足 \(G'\) 是连通二分图. \(n\le 20,m\le\dfrac{n(n-1)}{2}\) 答案对 \(998244353\) 取模. 输入样例 #1: 3 3 1 2 1 3 2 3 输出样例 #1: 9 众所周知,…