Codeforces Round #423 (Div. 1, rated, based on VK Cup Finals) A.String Reconstruction B. High Load C. DNA Evolution 题意:给定一个只包含A,T,C,G的字符串S,有如下两种操作 1)修改一个点的字母. 2)给定一个字符串e ($\left | e \right |\leq 10$),生成一个由e重复组成的新串,eee...,问$S_{l..r}$中有几个字母跟这个新的字符串一一对应…

E. DNA Evolution 题目连接: http://codeforces.com/contest/828/problem/E Description Everyone knows that DNA strands consist of nucleotides. There are four types of nucleotides: "A", "T", "G", "C". A DNA strand is a seque…

Everyone knows that DNA strands consist of nucleotides. There are four types of nucleotides: "A", "T", "G", "C". A DNA strand is a sequence of nucleotides. Scientists decided to track evolution of a rare species, wh…

D. High Load 题目连接: http://codeforces.com/contest/828/problem/D Description Arkady needs your help again! This time he decided to build his own high-speed Internet exchange point. It should consist of n nodes connected with minimum possible number of…

C. String Reconstruction 题目连接: http://codeforces.com/contest/828/problem/C Description Ivan had string s consisting of small English letters. However, his friend Julia decided to make fun of him and hid the string s. Ivan preferred making a new strin…

A.题目链接:http://codeforces.com/contest/828/problem/A 解题思路: 直接暴力模拟 #include<bits/stdc++.h> using namespace std; int main() { ,ans=,a[]; cin>>m>>d>>s; ;i<m;i++){ cin>>a[i]; &&d) d--; &&d==&&s){ s--;num+…

Arkady needs your help again! This time he decided to build his own high-speed Internet exchange point. It should consist of n nodes connected with minimum possible number of wires into one network (a wire directly connects two nodes). Exactly k of t…

Ivan had string s consisting of small English letters. However, his friend Julia decided to make fun of him and hid the string s. Ivan preferred making a new string to finding the old one. Ivan knows some information about the string s. Namely, he re…

Pronlem A In a small restaurant there are a tables for one person and b tables for two persons. It it known that n groups of people come today, each consisting of one or two people. If a group consist of one person, it is seated at a vacant one-seate…

题目链接:http://codeforces.com/contest/828 A. Restaurant Tables time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output In a small restaurant there are a tables for one person and b tables for two pers…

昨晚一个瓜皮说今晚有cf,听说是晚间场,我瞅了一眼,娃,VK Cup,上分的好机会,看着比赛时间就有点心酸了,0:35,当时一直在纠结要不要打的问题,当时想着应该不难吧,要不打一下吧,要不还是看看题先,如果容易就打,难的话就不打了好的吧!于是就这样愉快的决定了.......cf日常延时10分钟,0:45,要不要去睡觉啊,干脆先睡一觉好了,然后又是忍不住诱惑在等待开始! 比赛一开始,瞅了一眼A,这不是一道水题嘛,直接敲啊,然后1分钟就搞定了,交了就过了,B题直接求边界点就好了,扫了一遍就过了,C题…

D. High Load time limit per test 2 seconds memory limit per test 512 megabytes input standard input output standard output Arkady needs your help again! This time he decided to build his own high-speed Internet exchange point. It should consist of n…

C. String Reconstruction time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Ivan had string s consisting of small English letters. However, his friend Julia decided to make fun of him and hid…

题意跟某道我出的等差子序列求最值非常像…… 反正询问的长度只有10种,你就建立10批树状数组,每组的公差是确定的,首项不同. 然后询问的时候只需要枚举询问串的每一位,找找这一位对应哪棵树状数组即可. 修改的时候会在10棵树状数组里修改,也是算算修改的位置对应哪一棵即可. 要注意,一共有4种字符,每个树状数组其实分成4个,就只需要单点修改,维护前缀和了…… #include<cstdio> #include<cstring> using namespace std; int n,m,…

让你构造一棵树(给定了总结点数和总的叶子数),使得直径最小. 就先弄个菊花图(周围一圈叶子,中间一个点),然后平均地往那一圈放其他的点即可. #include<cstdio> using namespace std; int n,K,Ks[200010],x[200010],y[200010],ans,e; int main(){ scanf("%d%d",&n,&K); for(int i=1;i<=K;++i){ Ks[i]=1; } int no…

在每个给出的子串的起始位置打个标记,记录的是从这里开始的最长子串. 然后输出的时候就扫,如果遇到开始位置,就从这里开始输出,如果其后被更长的覆盖,就跳转到更长的串进行输出. 如果位置没被覆盖,就输出'a'. #include<cstdio> #include<string> #include<algorithm> #include<iostream> using namespace std; string s[100010]; int n,m,p[20000…

DNA Evolution 题目让我们联想到树状数组或者线段树,但是如果像普通那样子统计一段的和,空间会爆炸. 所以我们想怎样可以表示一段区间的字符串. 学习一发大佬的解法. 开一个C[10][10][4][n],就可以啦,第二维表示e的长度,第一维表示i%e的长度,第三维表示颜色,第四维求和了. #include <bits/stdc++.h> using namespace std; ; char s[maxn]; map<char,int> mp; ][][][maxn];…

http://codeforces.com/contest/831 A. Unimodal Array time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Array of integers is unimodal, if: it is strictly increasing in the beginning; after that…

Polycarp watched TV-show where k jury members one by one rated a participant by adding him a certain number of points (may be negative, i. e. points were subtracted). Initially the participant had some score, and each the marks were one by one added…

A:链接:http://codeforces.com/contest/831/problem/A 解题思路: 从前往后分别统计递增,相等,递减序列的长度,如果最后长度和原序列长度相等那么就输出yes: 实现代码: #include<bits/stdc++.h> using namespace std; int main() { ,a[]; cin>>m; ;i<m;i++){ cin>>a[i]; } ;i<m-;i++){ ]) ans++; else b…

题目传送门 传送门I 传送门II 传送门III 题目大意 求一个满足$d\sum_{i = 1}^{n} \left \lceil \frac{a_i}{d} \right \rceil - \sum_{i = 1}^{n} a_{i} \leqslant K$的最大正整数$d$. 整理一下可以得到条件是$d\sum_{i = 1}^{n} \left \lceil \frac{a_i}{d} \right \rceil \leqslant K + \sum_{i = 1}^{n} a_{i}$…

There are n people and k keys on a straight line. Every person wants to get to the office which is located on the line as well. To do that, he needs to reach some point with a key, take the key and then go to the office. Once a key is taken by somebo…

Vasily has a deck of cards consisting of n cards. There is an integer on each of the cards, this integer is between 1 and 100 000, inclusive. It is possible that some cards have the same integers on them. Vasily decided to sort the cards. To do this,…

Array of integers is unimodal, if: it is strictly increasing in the beginning; after that it is constant; after that it is strictly decreasing. The first block (increasing) and the last block (decreasing) may be absent. It is allowed that both of thi…

A. Unimodal Array time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Array of integers is unimodal, if: it is strictly increasing in the beginning; after that it is constant; after that it is…

题目链接:http://codeforces.com/contest/831/problem/D 题意:在一个一维坐标里,有n个人,k把钥匙(钥匙出现的位置不会重复并且对应位置只有一把钥匙),和一个终点p.问你每个人都拿到一把钥匙并且回到终点的情况下,n个人之中所花时间最长的那个人时间最少是多少?(一秒只能走一个单位的距离) 思路:考虑二分x,x为每个人能走的步数.对于两个人a,b和两把钥匙c,d 那么当p[a]<p[b]并且p[c]<p[d]时, a拿c钥匙,b拿d钥匙是最优的,因为对于p[…

题目链接:http://codeforces.com/contest/831/problem/C 题意:给定k个评委,n个中间结果. 假设参赛者初始分数为x,按顺序累加这k个评委的给分后得到k个结果,在这个过程中,某人只记得其中n次结果(n次结果不一样按照时间顺序来排列),问你参赛者的初始合法分数有多少种. 思路:维护一个评委给分的前缀和,然后枚举每一种可能的初始分数,然后判断当前枚举的这个分数经过k次累加分数后得到的k个结果有n个结果等于给定的中间结果即可. #define _CRT_SECU…

题目链接:http://codeforces.com/contest/831/problem/B 题意:给第2个26个字母并不重复的字符串(2个字符串对于一个映射),第1个字符串为key集合,第2个字符串为对应的value集合. 然后给了一个字符串(包括小写字母和数字),按照映射规则输出结果(数字不变,字母则对照给定2个字符串的映射规则,大写字母先转换成对应小写字母然后映射完之后在转换成对应的大写字母) 思路:按照题目意思模拟即可. #define _CRT_SECURE_NO_DEPRECAT…

题目链接:http://codeforces.com/contest/831/problem/A 题意:给定一个序列,问你这个序列是否是单峰的. 定义单峰的序列为: (序列值的变化趋势)开始是递增的,然后是平缓的,最后是递减的. 对于开始(递增)和结尾(递减)的那部分可以不出现 思路:按照题目判即可. import java.io.*; import java.util.*; public class Main { public static final int MAXN=100+24; pub…

当时晚上打CF时候比较晚,加上是集训期间的室友都没有晚上刷题的习惯,感觉这场CF很不在状态.A题写复杂WA了一发后去厕所洗了个脸冷静了下,换个简单写法,可是用cin加了ios::sync_with_stdio(false)还是WA了,真无语.B题读半天题,读懂后轻松A了,看了下比赛时间就快结束了,把C题读了一遍后,感觉能做,最后还是选择了睡觉23333.................. A题大意:平平平 增平减 ,缺任一都可,判断是否为这样的数列 #include<stdio.h> #inc…