转载请注明出处: http://www.cnblogs.com/fraud/          ——by fraud Vasily the Bear and Beautiful Strings Vasily the Bear loves beautiful strings. String s is beautiful if it meets the following criteria: String s only consists of characters 0 and 1, at that…

题意: 给出n,m,g,求好串的个数 0 <= n,m <= 10^5,n + m >= 1,0 <= g <= 1 好串的定义: 1.只由0,1组成,并且恰好有n个0,m个1 2.串的value = g 串的value的计算方式: 每次将最后2个字符替换,直至串的长度为1,该字符就是串的value 00 -> 1,   01,11,10 -> 0 solution: 首先,总方案数 = C(n + m, m) m = 0时,特殊判断 设f(n,m)为n个0,m个…

这场CF,脑子乱死啊...C题,搞了很长时间,结束了,才想到怎么做.B题,没看,D题,今天看了一下,很不错的组合题. 如果n和m都挺多的时候 以下情况都是变为1,根据偶数个0,最后将会为1,奇数个0,最后变为0,以1开头,全都是0. 0 1.. 0 0 0 1.... 0 0 0 0 0 1.... 总的情况是C(n+m,m),算1也可以算出来.注意m = 1的时候特判,0的时候,我也全写的特判. 10^5的组合数,用费马小定理求逆元.看了下题解,题解直接来了个逆元.. inv(a) = a^(…

转载请注明出处: http://www.cnblogs.com/fraud/          ——by fraud Vasily the Bear and Sequence Vasily the bear has got a sequence of positive integers a1, a2, ..., an. Vasily the Bear wants to write out several numbers on a piece of paper so that the beauty…

题目链接:http://codeforces.com/problemset/problem/336/C 题目意思:给出一个递增的正整数序列 a1, a2, ..., an,要求从中选出一堆数b1, b2, ..., bk,这堆数进行完按位&运算之后(b1 and b2 and ... and bk),能被2v整除.除此,还要求所选中的这堆数是两两不同的,&之后要最大,换句话来说,v 要尽可能最大,如果找到最大的v的方法有多种,即在 a1, a2, ..., an 中有很多种不同的组合 &a…

题目链接:http://codeforces.com/problemset/problem/336/A 好简单的一条数学题,是8月9日的.比赛中没有做出来,今天看,从pupil变成Newbie了,那个伤心啊----不是分数的缘故,而是心态!!!昨晚一直卡机,网页很久才打得开,35min才进入比赛页面,接着做的时候又非常浮躁,静不下心来,提交时再次卡机,临20多min才提交成功,于是罢想!!心态真不好!!!这是第一次做题做得那么糟糕,要端正心态才行,遇到什么紧急情况都要冷静,保持清醒的头脑. 题意…

C. Vasily the Bear and Sequence time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Vasily the bear has got a sequence of positive integers a1, a2, ..., *a**n*. Vasily the Bear wants to write o…

链接: https://codeforces.com/contest/1265/problem/A 题意: A string is called beautiful if no two consecutive characters are equal. For example, "ababcb", "a" and "abab" are beautiful strings, while "aaaaaa", "abaa&…

水题,注意数据范围即可 #include <iostream> #include <algorithm> #include <utility> using namespace std; typedef pair<int,int> Point; int main(){ int x,y; cin >> x >>y; Point a,b; if((x>0 && y > 0) || (x < 0 &&…

C. Bear and String Distance 题目连接: http://www.codeforces.com/contest/628/problem/C Description Limak is a little polar bear. He likes nice strings - strings of length n, consisting of lowercase English letters only. The distance between two letters is…