time limit per test2 seconds memory limit per test256 megabytes inputstandard input outputstandard output Roman planted a tree consisting of n vertices. Each vertex contains a lowercase English letter. Vertex 1 is the root of the tree, each of the n …

链接:http://codeforces.com/problemset/problem/570/D D. Tree Requests time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Roman planted a tree consisting of n vertices. Each vertex contains a low…

题目链接 可以发现 十进制4 对应 二进制100 十进制16 对应 二进制10000 十进制64 对应 二进制1000000 可以发现每多两个零,4的次幂就增加1. 用string读入题目给定的二进制数字,求出其长len,当len为奇数时,第一位为1,后面的位数如果都为0,则输出len,如果有一个不为0,则输出len+1: 当len为偶数时,则输出len.(之所以这样输出是因为题目给定4的次幂是从0开始的) #include<iostream> #include<string> #…

题目链接: 570 D. Tree Requests 题目描述: 给出一棵树,有n个节点,1号节点为根节点深度为1.每个节点都有一个字母代替,问以结点x为根的子树中高度为h的后代是否能够经过从新排序变成一个回文串? 解题思路: 判断是不是回文串,可以统计集合中出现过的字母的个数,出现奇数次的字母个数小于1,即为回文串,否则不是.所以我们可以使用状压统计当前区间中字母出现的奇偶次数. 对于如何快速的求出区间,先dfs整棵树,标记下来每个节点进栈的时间和出栈的时间,然后把高度一样的点按照进栈时间顺序…

题意:给出一棵树.每一个结点都有一个字母,有非常多次询问,每次询问.以结点v为根的子树中高度为h的后代是否可以经过调整变成一个回文串. 做法: 推断能否够构成一个回文串的话,仅仅须要知道是否有大于一个的奇数数目的字母就可以.为了非常快的訪问到一个区间.记录前缀和就可以.为了省内存,状压奇偶就可以. 为了非常快的找到以结点v为根的子树中高度为h的后代,须要dfs整棵树.然后记录每一个结点第一次訪问它的时间戳以及离开它的时间戳,就能够二分出来. 为了省内存,能够离线处理询问. #include<ma…

time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output People do many crazy things to stand out in a crowd. Some of them dance, some learn by heart rules of Russian language, some try to become a…

time limit per test2 seconds memory limit per test256 megabytes inputstandard input outputstandard output Professor GukiZ doesn't accept string as they are. He likes to swap some letters in string to obtain a new one. GukiZ has strings a, b, and c. H…

time limit per test4 seconds memory limit per test256 megabytes inputstandard input outputstandard output Anton is playing a very interesting computer game, but now he is stuck at one of the levels. To pass to the next level he has to prepare n potio…

time limit per test1 second memory limit per test256 megabytes inputstandard input outputstandard output Anton likes to play chess, and so does his friend Danik. Once they have played n games in a row. For each game it's known who was the winner - An…

time limit per test2 seconds memory limit per test512 megabytes inputstandard input outputstandard output Genos recently installed the game Zuma on his phone. In Zuma there exists a line of n gemstones, the i-th of which has color ci. The goal of the…