Problem  Codeforces Round #556 (Div. 2) - D. Three Religions Time Limit: 1000 mSec Problem Description Input Output Sample Input 51 2 1 2 1 Sample Output 1 1 1 2 2 题解:这个题有做慢了,这种题做慢了和没做出来区别不大... 读题的时候脑子里还意识到素数除了2都是奇数,读完之后就脑子里就只剩欧拉筛了,贪心地构造使得前缀和是连续的素数,那…

Codeforces Round #556 (Div. 1) A. Prefix Sum Primes 给你一堆1,2,你可以任意排序,要求你输出的数列的前缀和中质数个数最大. 发现只有\(2\)是偶质数,那么我们先放一个\(2\),再放一个\(1\),接下来把\(2\)全部放掉再把\(1\)全部放掉就行了. #include<iostream> #include<cstdio> using namespace std; inline int read() { int x=0;bo…

Problem  Codeforces Round #556 (Div. 2) - D. Three Religions Time Limit: 3000 mSec Problem Description Input Output Sample Input 6 8abdabc+ 1 a+ 1 d+ 2 b+ 2 c+ 3 a+ 3 b+ 1 c- 2 Sample Output YESYESYESYESYESYESNOYES 题解:动态规划,意识到这个题是动态规划之后难点在于要优化什么东西,本题…

A. Stock Arbitraging 直接上代码: #include<cstdio> #include<cstring> #include<iostream> #include<algorithm> #include<queue> #include<stack> #include<set> #include<map> #include<vector> #include<cmath>…

Codeforces Round #521 (Div. 3)  E. Thematic Contests 题目传送门 题意: 现在有n个题目,每种题目有自己的类型要举办一次考试,考试的原则是每天只有一种题目类型一种题目类型只能出现在一天每天的题目类型不能相同,而且后一天的题目数量必须正好为前一天的两倍,第一天的题目数量是任意的求怎么安排能使题目尽量多.注意:不是天数尽量多 思路: 首先我们知道一件事,题目属于哪种类型并不重要,重要的是每种类型的个数所以我们先统计出所有类型的个数,存进一个数组,而…

B. Modulo Sum Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/577/problem/B Description You are given a sequence of numbers a1, a2, ..., an, and a number m. Check if it is possible to choose a non-empty subsequence aij such…

E. Product Sum 题目连接: http://www.codeforces.com/contest/631/problem/E Description Blake is the boss of Kris, however, this doesn't spoil their friendship. They often gather at the bar to talk about intriguing problems about maximising some values. Thi…

 传送门 Description Little Chris is very keen on his toy blocks. His teacher, however, wants Chris to solve more problems, so he decided to play a trick on Chris. There are exactly s blocks in Chris's set, each block has a unique number from 1 to s. Chr…

D. On Sum of Fractions Let's assume that v(n) is the largest prime number, that does not exceed n; u(n) is the smallest prime number strictly greater than n. Find . Input The first line contains integer t (1 ≤ t ≤ 500) — the number of testscases. Eac…

题目链接: 题目 D. Toy Sum time limit per test:1 second memory limit per test:256 megabytes 问题描述 Little Chris is very keen on his toy blocks. His teacher, however, wants Chris to solve more problems, so he decided to play a trick on Chris. There are exactly…

比赛链接 A 贪心 #include <cstdlib> #include <cstdio> #include <algorithm> #include <cmath> #include <cstring> #include <queue> #include <vector> #include <set> using namespace std; const int N = 1005; int a[N], b[…

B. Modulo Sum time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output You are given a sequence of numbers a1, a2, ..., an, and a number m. Check if it is possible to choose a non-empty subsequence…

D. Toy Sum   time limit per test:1 second memory limit per test:256 megabytes input:standard input output:standard output Little Chris is very keen on his toy blocks. His teacher, however, wants Chris to solve more problems, so he decided to play a t…

直接O(n*m)的dp也可以直接跑过. 因为上最多跑到m就终止了,因为前缀sum[i]取余数,i = 0,1,2,3...,m,有m+1个余数,m的余数只有m种必然有两个相同. #include<bits/stdc++.h> using namespace std; ; int cnt[maxn]; bool dp[maxn][maxn]; #define Y { puts("YES"); return 0; } int main() { //freopen("i…

E. Product Sum   Blake is the boss of Kris, however, this doesn't spoil their friendship. They often gather at the bar to talk about intriguing problems about maximising some values. This time the problem is really special. You are given an array a o…

                                                         B. Modulo Sum                                                                                                  time limit per test 2 seconds                                                    …

题目链接:http://codeforces.com/contest/1150/problem/D 题目大意: 你有一个参考串 s 和三个装载字符串的容器 vec[0..2] ,然后还有 q 次操作,每次操作你可以选择3个容器中的任意一个容器,往这个容器的末尾添加一个字符,或者从这个容器的末尾取出一个字符. 每一次操作之后,你都需要判断:三个容器的字符串能够表示成 s 的三个不重叠的子序列. 比如,如果你的参考串 s 是: abdabc 而三个容器对应的字符串是: vec[0]:ad vec[1…

B. Odd Sum Segments time limit per test3 seconds memory limit per test256 megabytes inputstandard input outputstandard output You are given an array a consisting of n integers a1,a2,-,an. You want to split it into exactly k non-empty non-intersecting…

传送门 B题题意: 给你n个数,让你把这n个数分成k个段(不能随意调动元素位置).你需要保证这k个段里面所有元素加起来的和是一个奇数.问可不可以这样划分成功.如果可以打印YES,之后打印出来是从哪里开始断开的. 否则打印出NO 题解: 加上奇数可以使和的性质改变,原来使偶数则变为奇数,奇数则变为偶数.加上一个偶数就不会有这样的变化.所以第一步就找出来有多少个奇数.因为要保证k个段的和都为奇数,所以每个段得先有一个奇数 剩下来的奇数数量如果是偶数那就不影响,这样就可以成功划分.如果是奇数那就划分不…

等比数列求和一定要分类讨论!!!!!!!!!!!! #include<bits/stdc++.h> #define LL long long #define fi first #define se second #define mk make_pair #define pii pair<int,int> #define ull unsigned long long using namespace std; ; +; const int inf=0x3f3f3f3f; const L…

题意:给你两个长度为\(n\)的01串\(s\)和\(t\),可以选择\(s\)的前几位,取反然后反转,保证\(s\)总能通过不超过\(2n\)的操作得到\(t\),输出变换总数,和每次变换的位置. 题解:我们现将\(s\)串全部变成\(1\)或\(0\),确保\(s[n]=t[n]\),然后我们倒着遍历\(t\),若遇到相邻的两个字符不同,我们就对\(s\)中相应的位置执行一次操作,然后继续遍历,如下图: 代码: int t; int n; char s[N],tmp[N]; vector<i…

题意:给你两个长度为\(n\)的01串\(s\)和\(t\),可以选择\(s\)的前几位,取反然后反转,保证\(s\)总能通过不超过\(3n\)的操作得到\(t\),输出变换总数,和每次变换的位置. 题解:构造题一定要充分利用题目所给的条件,对于\(s\)中的某一位i,假如它和\(t\)中的对应位置不同,我们先对前i个字符取反反转,然后再对第一个字符取反反转(就选了一个,反不反都无所谓),在取前i个位置取反反转,这样,我们就将第i个位置变换了,消耗了3次操作.这样就一定能保证在\(3n\)之内完…

The link to problem:Problem - D - Codeforces   D. Range and Partition  time limit per test: 2 seconds memory limit per test: 256 megabytes input: standard input output: standard output Given an array a of n integers, find a range of values [x,y] (x≤y…

https://codeforces.com/contest/1139/problem/F 题意 有m个人,n道菜,每道菜有\(p_i\),\(s_i\),\(b_i\),每个人有\(inc_j\),\(pref_j\),一个人可以买一道菜的条件是 1. \(p_i \leq inc_j \leq s_i\) 2. \(|b_i - pref_j| \leq inc_j-p_i\) ,问每个人分别能买多少道菜 题解 转化一下公式 \(p_i \leq inc_j \leq s_i\) 下面两个满…

题意 给你N个数字和一个K,问一共有几种拼接数字的方式使得到的数字是K的倍数,拼接:“234”和“123”拼接得到“234123” 分析: N <= 2e5,简单的暴力O(N^2)枚举肯定超时 数字A和B拼接,B的位数最多10位,如果我们知道位数为(1-10)的数字和A拼接满足是K的倍数这样的数字有几个,就可以在N*10的复杂度下完成所有的拼接 在读入数据的时候,我们可以统计出数字的位数和对K取余的结果,这样我们就可以在O(1)的时间内得到所有满足的情况 #include<bits/stdc+…

传送门 D. Arthur and Walls time limit per test 2 seconds memory limit per test 512 megabytes input standard input output standard output Finally it is a day when Arthur has enough money for buying an apartment. He found a great option close to the cente…

链接: https://codeforces.com/contest/1230/problem/C 题意: Anadi has a set of dominoes. Every domino has two parts, and each part contains some dots. For every a and b such that 1≤a≤b≤6, there is exactly one domino with a dots on one half and b dots on th…

题目链接:https://codeforces.com/contest/1417/problem/C 题意 给出一个大小为 $n$ 的数组 $a$,计算当 $k$ 从 $1$ 到 $n$ 取值时在所有 $k$ 长区间中出现的数的最小值. 题解 记录一个值两两间的最大距离,该距离的 $k$ 长区间及之后更长的区间都可能以该值为最小值. Tips 注意两端的处理. 代码一 #include <bits/stdc++.h> using namespace std; int main() { ios:…

题意:你的手机有\(n\)个app,每个app的大小为\(a_i\),现在你的手机空间快满了,你需要删掉总共至少\(m\)体积的app,每个app在你心中的珍惜值是\(b_i\),\(b_i\)的取值为\(1\)或\(2\),现在问你至少删掉体积\(m\)的app的最小珍惜值是多少,如果不能满足条件,输出\(-1\). 题解:因为\(b_i\)的取值只有\(1\)和\(2\),所以我们肯定优先选珍惜值\(1\)的体大的app,这样贪心的话,我们将\(1\)和\(2\)分开,从大排序,记录\(1\…

C. Alyona and mex Problem Description: Alyona's mother wants to present an array of n non-negative integers to Alyona. The array should be special. Alyona is a capricious girl so after she gets the array, she inspects m of its subarrays. Subarray is…