传送门 有向图生成树计数 (度数 ->入度->外向树) BEST定理 (不定起点的欧拉回路个数=某点为根的外向树个数(存在欧拉回路->每个点为根的外向树个数相等)*(每个点的度数(存在欧拉回路->每个点入度=出度)-1)的阶层) 一个题解的传送门 //Achen #include<algorithm> #include<iostream> #include<cstring> #include<cstdlib> #include<…

2017 多校3 hdu 6061 RXD and functions(FFT) 题意: 给一个函数\(f(x)=\sum_{i=0}^{n}c_i \cdot x^{i}\) 求\(g(x) = f(x - \sum a_i)\)后每一项\(x^{i}\)的系数mod998244353 \(n <= 10^{5},m <= 10^{5}\) \(0 <= c_i < 998244353\) \(0 <= a_i < 998244353\) 思路: 令\(d = -\s…

每次NTT都忘记初始化,真的是写一个小时,Debug两个小时- - /* HDU 6061 - RXD and functions [ NTT ] | 2017 Multi-University Training Contest 3 题意: 给定多项式 F(x) = ∑[0<=i<=n] f(i)*x^i 求多项式 G(x) = F(x-a) n <= 1e5 分析: 设 G(x) = ∑ g(i)*x^i 将 F(x-a) 按二项式定理展开后易得: g(x) = ∑[x<=y&l…

/* HDU 6060 - RXD and dividing [ 分析,图论 ] | 2017 Multi-University Training Contest 3 题意: 给一个 n 个节点的树,要求将 2-n 号节点分成 k 部分,然后将每一部分加上节点 1, 每一个子树的 val 为最小斯坦纳树,求总的最大 val 分析: 考虑每条边下面所在的子树,大小为num 由于该子树至多被分成 k 块,故该边最多贡献 k 次,贡献次数当然是越多越好 所以每条边的贡献为 w * min(k, num…

比赛时候面向过题队伍数目 打表- - 看了题解发现确实是这么回事,分析能力太差.. /* HDU 6063 - RXD and math [ 数学,规律 ] | 2017 Multi-University Training Contest 3 题意: 求 Σ μ(i)^2 * sqrt( n^k/i ) [ 1 <= i<= n^k ] n,k <= 1e18 分析: 首先 μ(i) 为莫比乌斯函数,若 i 是完全平方数的倍数则 μ(i) = 0 ,否则 μ(i) = ±1 所以只有不是…

RXD and math Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 524288/524288 K (Java/Others)Total Submission(s): 568    Accepted Submission(s): 306 Problem Description RXD is a good mathematician.One day he wants to calculate: ∑i=1nkμ2(i)×⌊nki−…

题目连接 http://acm.hdu.edu.cn/showproblem.php?pid=5272 Dylans loves numbers Description Who is Dylans?You can find his ID in UOJ and Codeforces.His another ID is s1451900 in BestCoder. And now today's problems are all about him. Dylans is given a number…

Dylans loves numbers Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://acm.hdu.edu.cn/showproblem.php?pid=5272 Description Dylans是谁?你可以在 UOJ 和 Codeforces上看到他.在BestCoder里,他有另外一个ID:s1451900.今天的题目都和他有关哦.Dylans得到了一个数N.他想知道N的二进制中有几组1.如果两个1之间有若干个(至少一个)0…

题目链接 Problem Description RXD is a good mathematician. One day he wants to calculate: ∑i=1nkμ2(i)×⌊nki−−−√⌋ output the answer module 109+7. 1≤n,k≤1018 μ(n)=1(n=1) μ(n)=(−1)k(n=p1p2-pk) μ(n)=0(otherwise) p1,p2,p3-pk are different prime numbers Input Th…

Humble Numbers Time Limit:1000MS     Memory Limit:32768KB     64bit IO Format:%I64d & %I64u Submit Status Practice HDU 1058 Description A number whose only prime factors are 2,3,5 or 7 is called a humble number. The sequence 1, 2, 3, 4, 5, 6, 7, 8, 9…