传送门: http://acm.hdu.edu.cn/showproblem.php?pid=1005 Number Sequence Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 198316    Accepted Submission(s): 49744 Problem Description A number sequence…

链接:传送门 题意:略 思路:f(n) = (A * f(n - 1) + B * f(n - 2)) mod 7 -> f(n) = (A * f(n-1)%7 + B * f(n-1)%7)%7 检查输出可以发现规律,每48个数一循环,因此只需要打出前50个数的fib表然后对n%7即可. /************************************************************************* > File Name: 1.cpp > Aut…

解题心得: 1.对于数据很大,很可怕,不可能用常规手段算出最后的值在进行mod的时候,可以思考找规律. 2.找规律时不必用手算(我傻,用手算了好久).直接先找前100项进行mod打一个表出来,直接看就行了. 3.对于像斐波那契数列(本题)的那样,凭借肉眼无法找到规律的时候,可以观察本题的特点.那就是,第一项和第二项不会变,都为1,1.所以循环的时候必定是以1.1为开始,中间的数可以直接记录,很玄幻. 4.还是边界问题,这很重要,这时候数列尽量从1开始,因为在询问的时候都是询问的第n个数,要时刻保…

A - Magic Number Time Limit:2000MS     Memory Limit:32768KB     64bit IO Format:%lld & %llu Submit Status Practice ZOJ 3622 Appoint description:   Description A positive number y is called magic number if for every positive integer x it satisfies tha…

C. Sequence (64 Mb, 1 sec / test)Integer sequences are very interesting mathematical objects. Let us examine a sequence generated with the use of two operations: doubling and “digit sorting”. The latter operation consists in ascending-order sort of t…

2014多校 第八题 1008 2014 Multi-University Training Contest 8 4952 Number Transformation Number Transformation Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 85 Accepted Submission(s): 31 Problem Descr…

Starting from point (0,0) on a plane, we have written all non-negative integers 0, 1, 2,... as shown in the figure. For example, 1, 2, and 3 has been written at points (1,1), (2,0), and (3, 1) respectively and this pattern has continued. You are to w…

I was trying to solve problem '1234 - Harmonic Number', I wrote the following code long long H( int n ) {    long long res = 0;    for( int i = 1; i <= n; i++ )        res = res + n / i;    return res;} Yes, my error was that I was using the integer…

题目链接 Problem Description Consider the aggregate An= { 1, 2, -, n }. For example, A1={1}, A3={1,2,3}. A subset sequence is defined as a array of a non-empty subset. Sort all the subset sequece of An in lexicography order. Your task is to find the m-th…

传送门 题意: 给出了三个新定义: E-prime : ∀ num ∈ E,不存在两个偶数a,b,使得 num=a*b;(简言之,num的一对因子不能全为偶数) E-prime factorization : 定义集合P由 E-prime 元素组成,定义 e = p1*p2*.....*pn:(p1,p2,....,pn ∈ P , |P| = n) E-factorial : 定义 e!! = 2*4*6*8*.........*e:(简言之,偶数e及其之前的偶数连乘积) 输出一个数 e ,求…

http://lightoj.com/volume_showproblem.php?problem=1245 G - Harmonic Number (II) Time Limit:3000MS     Memory Limit:32768KB     64bit IO Format:%lld & %llu Submit Status Practice LightOJ 1245 Description I was trying to solve problem '1234 - Harmonic…

找到规律模拟就可以了,用DFS模拟很简洁,用循环模拟比较直观(大概吧) 注意输入输出用%llu,1ULL<<64=0!被这几个小问题卡了好久 #include <cstdio> #include <algorithm> #include <cstring> using namespace std; int T; unsigned long long n,p,q; unsigned long long path; int lev; int main() { s…

题目链接: http://codeforces.com/gym/101194/attachments https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=5919 题意: 给出正整数 $N(1 \le N \le 10^5)$,询问对于正整数 $k$,有多少个小于 $2^N$ 的 $2^k-1$ 是 $7$ 的整数倍. 题解: $…

Number Sequence Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 187893    Accepted Submission(s): 46820 Problem Description A number sequence is defined as follows: f(1) = 1, f(2) = 1, f(n) = (A…

题目链接: http://codeforces.com/problemset/problem/353/D?mobile=true H. Queue time limit per test 1 secondmemory limit per test 256 megabytes 问题描述 There are n schoolchildren, boys and girls, lined up in the school canteen in front of the bun stall. The b…

题目传送门 /* 题意:汉诺塔问题变形,多了第四个盘子可以放前k个塔,然后n-k个是经典的汉诺塔问题,问最少操作次数 递推+高精度+找规律:f[k]表示前k放在第四个盘子,g[n-k]表示经典三个盘子,2 ^ (n - k) - 1 所以f[n] = min (f[k] * 2 + g[n-k]),n<=10000,所要要用高精度,另外打表能看出规律 */ /************************************************ * Author :Running_Ti…

题目: A single positive integer i is given. Write a program to find the digit located in the position i in the sequence of number groups S1S2...Sk. Each group Sk consists of a sequence of positive integer numbers ranging from 1 to k, written one after…

题意: 给出递推式 g(n) = 3g(n - 1) + g(n - 2),且g(1) = 1,g(0) = 0.求g( g( g(n))) mod 109 + 7. 思路: 要求的g( g( g(n)))一共里外3层.看到时间限制1s,数据最大10^18,必定不能老实递推,要么有循环,要么用通项公式.这里用通项公式太麻烦了,数字不好算,而g(n)%109 + 7是有规律的, 在n=222222224之后会出现循环,也就是n=0和n=222222224的g(n)是一样的,这是最外层.那么也就是说…

题目 第一次做是看了大牛的找规律结果,如下: //显然我看了答案,循环节点是48,但是为什么是48,据说是高手打表出来的 #include<stdio.h> int main() { ],a,b,i,n; f[]=;f[]=; while(scanf("%d%d%d",&a,&b,&n)!=EOF) { &&b==&&n==)break; ;i<;i++) { f[i]=(a*f[i-])%+(b*f[i-])%…

Problem B Number Sequence Input: standard input Output: standard output Time Limit: 1 second A single positive integer i is given. Write a program to find the digit located in the position i in the sequence of number groups S1S2…Sk. Each group Sk con…

评:如果直接找$a_n$的二阶递推式:$a_{n+2}-2\sqrt{2}a_{n+1}-a_n=0$有根号,不利于估计尾数.…

Description 轮状病毒有很多变种,所有轮状病毒的变种都是从一个轮状基产生的.一个N轮状基由圆环上N个不同的基原子 和圆心处一个核原子构成的,2个原子之间的边表示这2个原子之间的信息通道.如下图所示 N轮状病毒的产生规律是在一个N轮状基中删去若干条边,使得各原子之间有唯一的信息通道,例如共有16个不 同的3轮状病毒,如下图所示 现给定n(N<=100),编程计算有多少个不同的n轮状病毒 Input 第一行有1个正整数n Output 计算出的不同的n轮状病毒数输出 Sample Inpu…

打个表出来看看,其实很明显. 推荐打这俩组 11 1 10 100 1000 10000 100000 1000000 10000000 100000000 1000000000 10000000000 12 1 10 100 1000 10000 100000 1000000 10000000 100000000 1000000000 10000000000 100000000000 打出表来看出来,n为偶数时,每隔两行,对原序列的奇数项分配的权重形成二项展开式. n为奇数时,每隔四行,形成二…

构造,递推,因为划分是合并的逆过程,考虑怎么合并. 先把N展开成全部为N个1然后合并,因为和顺序无关,所以只和出现次数有关情况有点多并且为了避免重复,分类,C[i]表示序列中最大的数为2^i时的方案数 树形表示合并 (UVA 10562 Undraw the Trees的表示方法...7          (2^0) (7表示2^0出现的次数)_ _ _|  |  |1 2 3    (2^1) (7个1可以合并成1~3个2) _ _   |  |   1 1         (2^2) (继续…

题意:一组男生女生在排队,每秒钟所有排在女生左边的男生与她相邻的女生交换位置,求女生全部换到男生前面的时间. 思路: 解法一:队伍最前面的那些女生不需要交换,后面的女生有两种状态:畅通无阻,前一个女生还没到达指定位置时到达前一个女生的下一个位置(被阻),花费时间分别为前面的男生数与前一个女生的时间+1.故从左边开始递推一遍. #include<cstdio> #include<cstring> #include<iostream> using namespace std…

http://acm.hdu.edu.cn/showproblem.php?pid=6129 [题意] 对于一个长度为n的序列a,我们可以计算b[i]=a1^a2^......^ai,这样得到序列b 重复这样的操作m次,每次都是从上次求出的序列a得到一个新序列b 给定初始的序列,求重复m次操作后得到的序列 [方法一] 假定n=5,我们模拟一次可以发现,经过m次操作后a1在b1......bn中出现的次数为: m=0: 1 0 0 0 0 m=2: 1 2 3 4 5 m=3: 1 3 6 10…

题目链接:https://cn.vjudge.net/problem/HDU-2045 找规律 代码 #include <cstdio> long long num[51][2]; int n; int main(void){ num[0][0]=2; num[0][1]=0; for (int i=0; i<50; i++){ num[i+1][0]+=num[i][0]+num[i][1]*2; num[i+1][1]+=num[i][0]; } while (scanf("…

先手动推出前10项,再上BM板子求出递推式 $A_n = 5A_{n-1} - 10A_{n-2} + 10A_{n-3} - 5A_{n-4} + A_{n-5}$,根据特征根理论可求出特征方程 $(x-1)^5$,设 $A_n = k_1n^4 + k_2n^3 + k_3n^2+k_4n+k_5$,代入前5项求出系数(用了高斯消元法解方程组). 这样虽然做出来了,但是感觉比较浪费时间,因为BM板子和高斯消元法的板子都不短,对手残狗不友好. 说明一下,差分法只能针对递推式的通项是对n的多项式…

任意门:https://nanti.jisuanke.com/t/31453 A.Hard to prepare After Incident, a feast is usually held in Hakurei Shrine. This time Reimu asked Kokoro to deliver a Nogaku show during the feast. To enjoy the show, every audience has to wear a Nogaku mask, a…

题目链接: Beauty of Sequence Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 813    Accepted Submission(s): 379 Problem Description Sequence is beautiful and the beauty of an integer sequence is def…