枚举开头结尾的字母,枚举ac的个数,总AC个数就是两个Fibonacci数列的和..... D. New Year Letter time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Many countries have such a New Year or Christmas tradition as writing a lett…

\(>Codeforces \space 379 F. New Year Tree<\) 题目大意 : 有一棵有 \(4\) 个节点个树,有连边 \((1,2) (1,3) (1,4)\) ,一共有 \(q\) 次操作,每次选择一个节点,新建两个节点 \(n + 1, n + 2\) 向其连边,每次操作完之后求树的直径的长度 $1 \leq q \leq 5 \times 10^5 $ 解题思路 : 观察发现,每次加点后,树的直径的端点至多只会变化一个 证明:首先显然新的直径的端点不可能是两个…

[题目链接]:http://codeforces.com/contest/379/problem/D [题意] 让你构造出两个长度分别为n和m的字符串s[1]和s[2] 然后按照连接的规则,顺序连接s[n-2]和s[n-1]得到s[n] (n>=3) 即s[n] = s[n-2]+s[n-1] 以此规则得到s[k]; 要求s[k]恰好出现x个"AC"子串; [题解] 暴力题; 枚举s1有ac1个"AC"子串,s2有ac2个"AC"子串; 这…

题意: 思路: Codeforces Round #370(Solved: 4 out of 5) A - Memory and Crow 题意:有一个序列,然后对每一个进行ai = bi - bi + 1 + bi + 2 - bi + 3.... 的操作,最后得到了a 序列,给定 a 序列,求原序列. 思路:水. #include <set> #include <map> #include <stack> #include <queue> #includ…

题目链接:http://codeforces.com/problemset/problem/379/D [题目大意] 告诉你初始字符串S1.S2的长度和递推次数k, 使用类似斐波纳契数列的字符串合并的递推操作,使得最后得到的字符串中刚好含有x个"AC",现在要你构造出满足条件的S1和S2. [分析] 最终结果中有些"AC"可能是应为在合并时一个字符串的尾部和另一个字符串的首部合并而成,这就跟原始字符串的首尾字符有关,不同的情况在K次递推后多产生的"AC&q…

原题地址:http://codeforces.com/contest/379/problem/D 题目大意:给出一种生成字符串的方法 s[k] = s[k - 2] + s[k - 1],其中加法意为将左右两个字符串直接相连,要求构造两个长度分别为n.m的字串s[1].s[2],使得按照这种方法得出的s[k]中恰好含有 x 个 “AC”(意思大家都懂的……)如果无解,输出“Happy new year!” 数据范围:3 ≤ k ≤ 50; 0 ≤ x ≤ 109; 1 ≤ n, m ≤ 100…

C. Letter Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/180/problem/C Description Patrick has just finished writing a message to his sweetheart Stacey when he noticed that the message didn't look fancy. Patrick was nervou…

A. Letter 题目连接: http://www.codeforces.com/contest/14/problem/A Description A boy Bob likes to draw. Not long ago he bought a rectangular graph (checked) sheet with n rows and m columns. Bob shaded some of the squares on the sheet. Having seen his mas…

E. Anton and Tree 题目连接: http://codeforces.com/contest/734/problem/E Description Anton is growing a tree in his garden. In case you forgot, the tree is a connected acyclic undirected graph. There are n vertices in the tree, each of them is painted bla…

D. Anton and Chess 题目连接: http://codeforces.com/contest/734/problem/D Description Anton likes to play chess. Also, he likes to do programming. That is why he decided to write the program that plays chess. However, he finds the game on 8 to 8 board to…