B. Proper Nutrition   time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Vasya has n burles. One bottle of Ber-Cola costs a burles and one Bars bar costs b burles. He can buy any non-negative…

B. Proper Nutrition time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Vasya has n burles. One bottle of Ber-Cola costs a burles and one Bars bar costs b burles. He can buy any non-negative in…

Proper Nutrition 题意:有n元钱,有2种单价不同的商品,是否存在一种购买方式使得钱恰好花光,如果有输入任意一种方式,如果没有输出“NO” 题解:可以使用拓展欧几里得快速求解. #include<iostream> using namespace std; #define ll long long ll gcd(ll a, ll b) { return b? gcd(b, a%b) : a; } void ex_gcd(ll a, ll b, ll &x, ll &…

A. Rounding time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Vasya has a non-negative integer n. He wants to round it to nearest integer, which ends up with 0. If n already ends up with 0, V…

[链接] 我是链接,点我呀:) [题意] 在这里输入题意 [题解] 可以直接一层循环枚举. 也可以像我这样用一个数组来存y*b有哪些. 当然.感觉这样做写麻烦了.. [代码] /* 1.Shoud it use long long ? 2.Have you ever test several sample(at least therr) yourself? 3.Can you promise that the solution is right? At least,the main ideal…

题目出处:http://codeforces.com/problemset/problem/898/B 题目大意:为一个整数能否由另外两个整数个整数合成 #include<iostream> using namespace std; int main(){ int n,a,b; cin>>n>>a>>b; == && a%== && b%== ){cout<<;} ){cout<<;} &&am…

C. Phone Numbers   time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Vasya has several phone books, in which he recorded the telephone numbers of his friends. Each of his friends can have on…

  A. Rounding   time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Vasya has a non-negative integer n. He wants to round it to nearest integer, which ends up with 0. If n already ends up with …

A /* Huyyt */ #include <bits/stdc++.h> #define mem(a,b) memset(a,b,sizeof(a)) #define mkp(a,b) make_pair(a,b) #define pb push_back ][] = {{, }, {, }, {, -}, { -, }, {, }, {, -}, { -, -}, { -, }}; using namespace std; typedef long long ll; int main()…

Codeforces Round #451 (Div. 2) A Rounding 题目链接: http://codeforces.com/contest/898/problem/A 思路: 小于等于5向下,大于补上差值输出 代码: #include <bits/stdc++.h> using namespace std; typedef long long ll; int main() { ll n; scanf("%I64d",&n); int r=n%10;…

Codeforces Round #452 (Div. 2) A Splitting in Teams 题目链接: http://codeforces.com/contest/899/problem/A 思路: 统计1和2出现的次数,尽量使2能够与1匹配尽可能多用.假设1再匹配完2之后还有剩余,则求出3个1可组成的方案 代码: #include <bits/stdc++.h> using namespace std; typedef long long ll; const int maxn =…

Rounding Solution Proper Nutrition 枚举 Solution Phone Numbers 模拟 Solution Alarm Clock 贪心,好像不用线段树也可以,事实证明我很擅长想得太多. Solution Squares and not squares 以后再也不用qsort了 Solution Restoring the Expression 用哈希真的很讨厌好吗?你们怎么从来不考虑冲突的问题,用的那么毫无负担呢? Splitting in Teams S…

When confronted with a problem , we think about it. The issue, of course, is that our efforts may be fruitful or they may not, depending on the effectiveness of the thinking done. Good thinking is focused thinking: we need to find the right focus for…

 Little Elephant and Chess Time Limit:2000MS     Memory Limit:262144KB     64bit IO Format:%I64d & %I64u Submit Status Practice CodeForces 259A Description The Little Elephant loves chess very much. One day the Little Elephant and his friend decided…

B. Alternating Current Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/343/problem/B Description Mad scientist Mike has just finished constructing a new device to search for extraterrestrial intelligence! He was in such a hu…

传送门 [http://codeforces.com/contest/898/problem/C] 题意 题意比较难理解直接看样例就知道了,给你个n接下来n行,每行包括一个名字和号码的数量,还有具体的每个号码 让你整理他的电话本,使得一个人的号码不能有重复,而且一个号码不能是另一个号码的后缀 分析 首先可以对一个人的所有号码去重,用map<string,set<string>> m来存信息可以,set具有惟一性,然后输出m.size()即为所有联系人 然后用三重循环来处理使得一个人…

id=46667" style="color:blue; text-decoration:none">CodeForces - 344D id=46667" style="color:blue; text-decoration:none">Alternating Current Time Limit: 1000MS   Memory Limit: 262144KB   64bit IO Format: %I64d & %I64…

传送门:http://codeforces.com/contest/898/problem/D 有n个闹钟,第i(1≤i≤n)个闹钟将在第ai(1≤ai≤106)分钟鸣响,鸣响时间为一分钟.当在连续的m分钟内,有至少k个闹钟鸣响,则会被叫醒.现要求关闭一些闹钟,使得在任意连续的m分钟内,鸣响的闹钟数量恒小于k. 可以贪心地求解这个问题. 首先,设置一个bool数组ison[],当有闹钟在第i分钟鸣响时,记ison[i]=1,否则ison[i]=0. 接下来,扫描整个时间区间[0..MAX_A].…

D. Alternating Current time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Mad scientist Mike has just finished constructing a new device to search for extraterrestrial intelligence! He was in…

PROBLEM D. Alarm Clock 题 OvO http://codeforces.com/contest/898/problem/D codeforces 898d 解 从前往后枚举,放进去后不合法就拿出来,记录拿出来的次数 中途每放进去一个数,会影响到一个区间,标记这个区间的首位(做差分,首+1,尾-1),同时维护这些标记的前缀和 #include <iostream> #include <cstring> #include <cmath> #includ…

上一次我们拿学校的URP做了个小小的demo.... 其实我们还可以把每个学生的证件照爬下来做成一个证件照校花校草评比 另外也可以写一个物理实验自动选课... 但是出于多种原因,,还是绕开这些敏感话题.. 今天,我们来扒一下cf的题面! PS:本代码不是我原创 1. 必要的分析 1.1 页面的获取 一般情况CF的每一个 contest 是这样的: 对应的URL是:http://codeforces.com/contest/xxx 还有一个Complete problemset页面,它是这样的:…

http://codeforces.com/contest/738/problem/D Galya is playing one-dimensional Sea Battle on a 1 × n grid. In this game a ships are placed on the grid. Each of the ships consists of bconsecutive cells. No cell can be part of two ships, however, the shi…

http://codeforces.com/contest/738/problem/C Vasya is currently at a car rental service, and he wants to reach cinema. The film he has bought a ticket for starts in t minutes. There is a straight road of length s from the service to the cinema. Let's…

http://codeforces.com/contest/738/problem/A Polycarp has interviewed Oleg and has written the interview down without punctuation marks and spaces to save time. Thus, the interview is now a string s consisting of n lowercase English letters. There is…

http://codeforces.com/problemset/problem/662/A 题目大意: 给定n(n <= 500000)张卡片,每张卡片的两个面都写有数字,每个面都有0.5的概率是在正面,各个卡牌独立.求把所有卡牌来玩Nim游戏,先手必胜的概率. (⊙o⊙)-由于本人只会在word文档里写公式,所以本博客是图片格式的. Code #include <cstdio> #include <cstring> #include <algorithm> u…

http://codeforces.com/problemset/problem/274/B 题目大意: 给定你一颗树,每个点上有权值. 现在你每次取出这颗树的一颗子树(即点集和边集均是原图的子集的连通图)且这颗树中必须包含节点1 然后将这颗子树中的所有点的点权+1或-1 求把所有点权全部变为0的最小次数(n<=10^5) 题解: 因为每一次的子树中都必须有1,所以我们得知每一次变换的话1的权值都会变化 所以我们以1为根 现在,我们发现,如果一个节点的权值发生变化,那么他的父节点的权值一定发生变…

http://codeforces.com/problemset/problem/261/B 题目大意:给定n个数a1-an(n<=50,ai<=50),随机打乱后,记Si=a1+a2+a3-+ai,问满足Si<=p的i的最大值的期望.(p<=50) (大意来自于http://www.cnblogs.com/liu-runda/p/6253569.html) 我们知道,全排列其实等价于我们一个一个地等概率地向一个序列里面插入数值 所以我们可以这么看这道题: 现在有n个数,有n个盒子…

http://codeforces.com/problemset/problem/696/B 题目大意: 这是一颗有n个点的树,你从根开始游走,每当你第一次到达一个点时,把这个点的权记为(你已经到过不同的点的数量+1) 每一次只有当子树中所有的点都已经游走过了再会向父亲走,走到每个儿子上的概率是相同的 对于每个点,求他的权的期望 (1 ≤ n ≤ 10^5) 题解: 首先我们发现,所有子树中所有的点的编号都一定比父亲要大 而且子树中的大小关系和我们访问它的顺序有关 如果对于一个节点u它的儿子为v…

http://codeforces.com/problemset/problem/148/D 题目大意: 原来袋子里有w只白鼠和b只黑鼠 龙和王妃轮流从袋子里抓老鼠.谁先抓到白色老鼠谁就赢. 王妃每次抓一只老鼠,龙每次抓完一只老鼠之后会有一只老鼠跑出来. 每次抓老鼠和跑出来的老鼠都是随机的. 如果两个人都没有抓到白色老鼠则龙赢.王妃先抓. 问王妃赢的概率. (0 ≤ w, b ≤ 1000). 题解: 其中第一行表示为王妃拿到的白色老鼠,自然是直接退出了 第二行表示为王妃拿到了黑色老鼠,但是因为…

http://codeforces.com/problemset/problem/453/A 题目大意: 给定一个m面的筛子,求掷n次后,得到的最大的点数的期望 题解 设f[i]表示掷出 <= i 的点数的概率 ans = sigma{i*(f[i]-f[i-1])} 单个f[i]直接快速幂计算 #include <cstdio> #include <cstring> #include <algorithm> using namespace std; typede…