Ivan likes to learn different things about numbers, but he is especially interested in really big numbers. Ivan thinks that a positive integer number x is really big if the difference between x and the sum of its digits (in decimal representation) is…

[codeforces 55]D. Beautiful numbers 试题描述 Volodya is an odd boy and his taste is strange as well. It seems to him that a positive integer number is beautiful if and only if it is divisible by each of its nonzero digits. We will not argue with this and…

C. Really Big Numbers time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Ivan likes to learn different things about numbers, but he is especially interested in really big numbers. Ivan thinks…

C. Tennis Championship(递推,斐波那契) 题意:n个人比赛,淘汰制,要求进行比赛双方的胜场数之差小于等于1.问冠军最多能打多少场比赛.题解:因为n太大,感觉是个构造.写写小数据,看看有没有结论. 2 3 4 5 6 7 8 9 10 11 12 (人数) 1 2 2 3 3 3 4 4 4 4 4 (比赛数) 发现比赛数的增长成斐波那契.维护一个前缀和即可. #include <bits/stdc++.h> #define ll long long using names…

Codeforces Beta Round #17 题目链接:点击我打开题目链接 大概题意: 给你 \(b\),\(n\),\(c\). 让你求:\((b)^{n-1}*(b-1)\%c\). \(2<=b<=10^{10^6},1<=n<=10^{10^6},1<=c<=10^9\) 简明题解: 因为 \(b\) , \(n\)都太大了.关键是求 \((b)^{n-1}\%c\) 所以,我们可以利用欧拉函数 \(phi()\) 的性质. 对于\(a^{b} \% c\…

Codeforces Round #597 (Div. 2 Consider the set of all nonnegative integers: 0,1,2,-. Given two integers a and b (1≤a,b≤104). We paint all the numbers in increasing number first we paint 0, then we paint 1, then 2 and so on. Each number is painted whi…

Alyona and Numbers 题目链接: http://acm.hust.edu.cn/vjudge/contest/121333#problem/A Description After finishing eating her bun, Alyona came up with two integers n and m. She decided to write down two columns of integers - the first column containing inte…

http://codeforces.com/problemset/problem/449/D 题意:给n个数,求and起来最后为0的集合方案数有多少 思路:考虑容斥,ans=(-1)^k*num(k),num(k)代表至少有k个数字and起来为1的方案数,那么怎么求num呢? 考虑and起来至少为x的方案数:那么一定是2^y-1,其中y代表有多少个数&x==x,问题就变成有多少数"包含"了某个数(二进制下),用dp解决这个问题:如果某一位数字是1,那么它一定能转移到它不是1的那…

Humble Numbers Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 17407    Accepted Submission(s): 7565 Problem Description A number whose only prime factors are 2,3,5 or 7 is called a humble numb…

题目链接:Codeforces 396B On Sum of Fractions 题解来自:http://blog.csdn.net/keshuai19940722/article/details/20076297 题目大意:给出一个n,ans = ∑(2≤i≤n)1/(v(i)*u(i)), v(i)为不大于i的最大素数,u(i)为大于i的最小素数, 求ans,输出以分式形式. 解题思路:一開始看到这道题1e9,暴力是不可能了,没什么思路,后来在纸上列了几项,突然想到高中时候求等差数列时候用到…