E. Pig and Palindromes   Peppa the Pig was walking and walked into the forest. What a strange coincidence! The forest has the shape of a rectangle, consisting of n rows and m columns. We enumerate the rows of the rectangle from top to bottom with num…

Hard problem 题目链接: http://codeforces.com/contest/706/problem/C Description Vasiliy is fond of solving different tasks. Today he found one he wasn't able to solve himself, so he asks you to help. Vasiliy is given n strings consisting of lowercase Engl…

C. Replacement Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/570/problem/C Description Daniel has a string s, consisting of lowercase English letters and period signs (characters '.'). Let's define the operation of replac…

C. ReplacementTime Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/570/problem/C Description Daniel has a string s, consisting of lowercase English letters and period signs (characters '.'). Let's define the operation of replace…

题意:给定一个字符串,里面有各种小写字母和' . ' ,无论是什么字母,都是一样的,假设遇到' . . ' ,就要合并成一个' .',有m个询问,每次都在字符串某个位置上将原来的字符改成题目给的字符,问每次须要多少次合并次数.才使字符串没有' .. ' 思路:最原始的想法,就是对于每一次询问,都遍历整个字符串.这样时间复杂度o(n*m),就高达10^10方,非常明显会tle. 换下思路,事实上每次询问所改变的字符都会保留到下一次.也就是下一次的次数就会受到上一次的影响,那么我仅仅要就算出第一次的…

思路:把n分成[1,n/2],[n/2+1,n],假设m在左区间.a=m+1,假设m在右区间,a=m-1.可是我居然忘了处理1,1这个特殊数据.被人hack了. 总结:下次一定要注意了,提交前一定要看下边界数据,不要急着交. 题目链接:http://codeforces.com/problemset/problem/570/B <pre name="code" class="cpp">#include<bits/stdc++.h> using…

题:https://codeforces.com/contest/570/problem/D 题意:给定一个以11为根的n个节点的树,每个点上有一个字母(a~z),每个点的深度定义为该节点到11号节点路径上的点数.每次询问a,ba,b查询以aa为根的子树内深度为bb的节点上的字母重新排列之后是否能构成回文串.分析:很明显是个树上启发式合并.显然,只要深度为bb结点的所有颜色中,至多有一种的数量为奇数就可以构成回文串了. #include<bits/stdc++.h> using namespa…

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 lowercase English letter. Vertex 1 is the root of the…

A. Elections time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output The country of Byalechinsk is running elections involving n candidates. The country consists of m cities. We know how many peopl…

Problem D: 题意:给定一棵n个点树,每个点有一个字母,有m个询问,每次询问某个节点x的子树中所有深度为k的点能否组成一个回文串 分析:一堆点能组成回文串当且仅当数量为奇数的字母不多于1个,显然这个状态可以用二进制表示 那么对于单个询问如何快速找到所有符合要求的点呢? 这里可以考虑树的dfs序,我们把深度相同的点按照dfs序加入集合中,易知在同一颗子树中的点肯定形成了一个连续的区间. 因此每次可以通过二分子树根节点的进入dfs序的时间和出dfs序的时间来找到这个区间 找到区间后可以根据预…

题目:Click here 题意:看一下题目下面的Note就会明白的. 分析:一开始想的麻烦了,用了树状数组(第一次用)优化,可惜没用. 直接判断: #include <bits/stdc++.h> using namespace std; typedef long long ll; const int INF = 0x3f3f3f3f; ; int n, m; char str[M]; int main() { while( ~scanf("%d %d", &n,…

题目:Click here #include <bits/stdc++.h> using namespace std; typedef long long ll; const int INF = 0x3f3f3f3f; +; int n, m; int main() { while( ~scanf("%d %d", &n, &m ) ) { ) { printf("1\n"); continue; } ) printf( ); else…

题目:Click here #include <bits/stdc++.h> using namespace std; typedef long long ll; const int INF = 0x3f3f3f3f; +; int n, m; ]; ]; int main() { while( ~scanf("%d%d", &n, &m ) ) { memset( b, , sizeof(b) ); ; i<=m; i++ ) { ; j<=n…

B. Simple Game time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output One day Misha and Andrew were playing a very simple game. First, each player chooses an integer in the range from 1 to n. Let'…

Description The country of Byalechinsk is running elections involving n candidates. The country consists of m cities. We know how many people in each city voted for each candidate. The electoral system in the country is pretty unusual. At the first s…

C. Replacement time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Daniel has a string s, consisting of lowercase English letters and period signs (characters '.'). Let's define the operation…

B. Simple Game time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output One day Misha and Andrew were playing a very simple game. First, each player chooses an integer in the range from 1 to n. Let'…

A. Elections time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output The country of Byalechinsk is running elections involving n candidates. The country consists of m cities. We know how many peopl…

A - Elections 题意: 每一场城市选举的结果,第一关键字是票数(降序),第二关键字是序号(升序),第一位获得胜利. 最后的选举结果,第一关键字是获胜城市数(降序),第二关键字是序号(升序),第一位获得胜利. 求最后选举获胜者. 思路: 直接模拟就可以. 代码: /* * @author FreeWifi_novicer * language : C++/C */ #include<cstdio> #include<iostream> #include<cstrin…

官方题解是离线询问,dfs树形转线性,然后二分找区间. 还有一种比较好的做法是直接dfs,将当前访问这个结点u相关的询问之前的状态存起来,然后访问完以后利用异或开关性,得到这颗子树上的答案. 代码是学习别人的http://blog.csdn.net/squee_spoon/article/details/47666667 #include<bits/stdc++.h> using namespace std; ; char s[maxn]; int head[maxn],to[maxn],nx…

先扫描一遍得到每个位置向后连续的'.'的长度,包含自身,然后在扫一遍求出初始的合并次数. 对于询问,只要对应位置判断一下是不是'.',以及周围的情况. #include<bits/stdc++.h> using namespace std; ; char s[maxn]; int post[maxn]; int main() { //freopen("in.txt","r",stdin); int n,m; scanf("%d%d",…

贪心,如果m分成的两个区间长度不相等,那么选长的那个区间最接近m的位置,否则选m-1位置,特判一下n等于1的情况 #include<bits/stdc++.h> using namespace std; int main() { int n,m; scanf("%d%d",&n,&m); ){ printf(; } , d2 = n-m; if(d1<d2){ printf(); }else { printf(); } ; }…

C. Replacement time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Daniel has a string s, consisting of lowercase English letters and period signs (characters '.'). Let's define the operation…

A. Elections time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output The country of Byalechinsk is running elections involving n candidates. The country consists of m cities. We know how many peopl…

题目链接 题意:对于m次询问 求解以vi为根节点 深度为hi的的字母能不能组合成回文串. 思路:暴力dsu找一边 简直就是神技! #include<bits/stdc++.h> #define ll long long int using namespace std; inline ll gcd(ll a,ll b){return b?gcd(b,a%b):a;} inline ll lcm(ll a,ll b){return a/gcd(a,b)*b;} int moth[13]={0,31…

Coloring Trees Problem Description: ZS the Coder and Chris the Baboon has arrived at Udayland! They walked in the park where n trees grow. They decided to be naughty and color the trees in the park. The trees are numbered with integers from 1 to n fr…

题目链接: http://codeforces.com/problemset/problem/268/E E. Playlist time limit per test 1 secondmemory limit per test 256 megabytes 问题描述 Manao's friends often send him new songs. He never listens to them right away. Instead, he compiles them into a play…

题目链接: http://codeforces.com/contest/464/problem/C J. Substitutes in Number time limit per test 1 secondmemory limit per test 256 megabytes 问题描述 Andrew and Eugene are playing a game. Initially, Andrew has string s, consisting of digits. Eugene sends A…

D. Fox And Jumping 题目连接: http://codeforces.com/contest/510/problem/D Description Fox Ciel is playing a game. In this game there is an infinite long tape with cells indexed by integers (positive, negative and zero). At the beginning she is standing at…

B. Maximum Submatrix 2 Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/problemset/problem/375/B Description You are given a matrix consisting of digits zero and one, its size is n × m. You are allowed to rearrange its rows. What is…