昨晚玩游戏竟然不小心错过了CF..我是有多浪啊. 今天总算趁着下课时间补了,感觉最后两题还是挺有意思的,写个题解. D: 题目大意: 给出一个括号序列,问有多少个子序列 是k个'(' + k个')' 这样的形式.        n<=200000 解法: 对于每个'('的位置,计算以它为最右边的'('的合法子序列数. 假设它左边(包括它)有$l$个'(', 右边有 $r$个')' ,  如果子序列的长度2k, 那么 方案数有$\binom{l-1}{k-1} * \binom{r}{k}= \b…

Codeforces Round #404 (Div. 2) 题意:对于 n and m (1 ≤ n, m ≤ 10^18)  找到 1) [n<= m] cout<<n; 2) [n>m]最小的 k => (k -m) * (k-m+1) >= (n-m)*2 成立 思路:二分搜索 #include <bits/stdc++.h> #include <map> using namespace std; #define LL long long…

D. Anton and School - 2 题目连接: http://codeforces.com/contest/785/problem/D Description As you probably know, Anton goes to school. One of the school subjects that Anton studies is Bracketology. On the Bracketology lessons students usually learn differ…

题目链接:http://codeforces.com/contest/785 A. Anton and Polyhedrons time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Anton's favourite geometric figures are regular polyhedrons. Note that there…

A. Anton and Polyhedrons time limit per test:2 seconds memory limit per test:256 megabytes input:standard input output:standard output Anton's favourite geometric figures are regular polyhedrons. Note that there are five kinds of regular polyhedrons:…

A. Anton and Polyhedrons 题目链接:http://codeforces.com/contest/785/problem/A 智障水题 实现代码: #include<bits/stdc++.h> using namespace std; int main(){ string s; ,t; cin>>t; while(t--){ cin>>s; if(s=="Tetrahedron") ans+=; else if(s==&quo…

C. Anton and Fairy Tale 题目连接: http://codeforces.com/contest/785/problem/C Description Anton likes to listen to fairy tales, especially when Danik, Anton's best friend, tells them. Right now Danik tells Anton a fairy tale: "Once upon a time, there liv…

B. Anton and Classes 题目连接: http://codeforces.com/contest/785/problem/B Description Anton likes to play chess. Also he likes to do programming. No wonder that he decided to attend chess classes and programming classes. Anton has n variants when he wil…

A - Anton and Polyhedrons 题目连接: http://codeforces.com/contest/785/problem/A Description Anton's favourite geometric figures are regular polyhedrons. Note that there are five kinds of regular polyhedrons: Tetrahedron. Tetrahedron has 4 triangular face…

http://codeforces.com/blog/entry/50996 官方题解讲得很明白,在这里我复述一下. 枚举每个左括号,考虑计算一定包含其的简单括号序列的个数,只考虑其及其左侧的左括号,以及其右侧的右括号.最后答案就是其之和. 可以将其提取出来这样((((((())),红色为当前左括号.设有x个左,y个右 要注意,这个答案为C(x+y-1,x),来证明. 我们只需证明,这个答案与长度为x+y-1的,包含x个1的零一序列的种类数相等即可. 随便写一个这样的零一序列,长度为x+y,但当…

好久没打CF了,打场div2练手.因为比较晚还没提前睡有点神志不清,E题打了莫名其妙的代码调了好久,最后结束后5分钟才发现哪里错了-- AC:ABCD Rank:60 A.Anton and Polyhedrons 题目大意:五种多面体,每种用一个英文单词表示,某人有n个多面体,分别告诉你这n个多面体是什么,求总共多少个面.(n<=200,000) 思路:普及培训,选择结构+循环结构. #include<cstdio> int main() { ;]; scanf("%d&qu…

题目链接 转自 给你一个字符串问你能构造多少RSBS. #include<bits/stdc++.h> #define LL long long #define fi first #define se second #define mp make_pair #define pb push_back using namespace std; LL gcd(LL a,LL b){return b?gcd(b,a%b):a;} LL lcm(LL a,LL b){return a/gcd(a,b)*…

A. Anton and Polyhedrons time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Anton's favourite geometric figures are regular polyhedrons. Note that there are five kinds of regular polyhedrons:…

A. Anton and Polyhedrons 直接统计+答案就可以了. #include<cstdio> #include<cstring> #include<algorithm> #include<cmath> #define maxn 1000 #define LL long long using namespace std; ]; int main() { int n; LL sum=; scanf("%d",&n);…

当m>=n时,显然答案是n: 若m<n,在第m天之后,每天粮仓减少的量会形成等差数列,只需要二分到底在第几天,粮仓第一次下降到0即可. 若直接解不等式,可能会有误差,需要在答案旁边扫一下. 注意二分上界的确定,不能太小也不能太大. #include<cstdio> #include<iostream> using namespace std; typedef long long ll; ll n,m; int main(){ cin>>n>>m;…

E. Anton and Permutation time limit per test 4 seconds memory limit per test 512 megabytes input standard input output standard output Anton likes permutations, especially he likes to permute their elements. Note that a permutation of n elements is a…

A. Anton and Polyhedrons Anton's favourite geometric figures are regular polyhedrons. Note that there are five kinds of regular polyhedrons: Tetrahedron. Tetrahedron has 4 triangular faces. Cube. Cube has 6 square faces. Octahedron. Octahedron has 8 …

题目这里 A.map裸题 #include <bits/stdc++.h> using namespace std; map <string, int> p; string s[] = { "Tetrahedron", "Cube", "Octahedron" , "Dodecahedron", "Icosahedron" }; , , , , }; int main() { ios…

Codeforces Round #403 (Div. 2, based on Technocup 2017 Finals) 说一点东西: 昨天晚上$9:05$开始太不好了,我在学校学校$9:40$放学我呆到十点然后还要跑回家耽误时间....要不然$D$题就写完了 周末一些成绩好的同学单独在艺术楼上课然后晚上下第一节晚自习和他们在回廊里玩开灯之后再关上一片漆黑真好玩 A.Andryusha and Socks 日常煞笔提.....我竟然$WA$了一次忘了$n<<1$ #include <…

Codeforces Round #366 (Div. 2) A I hate that I love that I hate it水题 #I hate that I love that I hate it n = int(raw_input()) s = "" a = ["I hate that ","I love that ", "I hate it","I love it"] for i in ran…

Codeforces Round #354 (Div. 2) Problems     # Name     A Nicholas and Permutation standard input/output 1 s, 256 MB    x3384 B Pyramid of Glasses standard input/output 1 s, 256 MB    x1462 C Vasya and String standard input/output 1 s, 256 MB    x1393…

直达–>Codeforces Round #368 (Div. 2) A Brain’s Photos 给你一个NxM的矩阵,一个字母代表一种颜色,如果有”C”,”M”,”Y”三种中任意一种就输出”#Color”,如果只有”G”,”B”,”W”就输出”#Black&White”. #include <cstdio> #include <cstring> using namespace std; const int maxn = 200; const int INF =…

 cf之路,1,Codeforces Round #345 (Div. 2) ps:昨天第一次参加cf比赛,比赛之前为了熟悉下cf比赛题目的难度.所以做了round#345连试试水的深浅.....       其实这个应该是昨天就写完的,不过没时间了,就留到了今天.. 地址:http://codeforces.com/contest/651/problem/A A. Joysticks time limit per test 1 second memory limit per test 256…

Codeforces Round #279 (Div. 2) 做得我都变绿了! Problems     # Name     A Team Olympiad standard input/output 1 s, 256 MB  x2377 B Queue standard input/output 2 s, 256 MB  x1250 C Hacking Cypher standard input/output 1 s, 256 MB  x740 D Chocolate standard in…

Codeforces Round #262 (Div. 2) 1003 C. Present time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Little beaver is a beginner programmer, so informatics is his favorite subject. Soon his info…

Codeforces Round #262 (Div. 2) 1004 D. Little Victor and Set time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Little Victor adores the sets theory. Let us remind you that a set is a group of…

A: 题目大意: 在一个multiset中要求支持3种操作: 1.增加一个数 2.删去一个数 3.给出一个01序列,问multiset中有多少这样的数,把它的十进制表示中的奇数改成1,偶数改成0后和给出的01序列相等(比较时如果长度不等各自用0补齐) 题解: 1.我的做法是用Trie数来存储,先将所有数用0补齐成长度为18位,然后就是Trie的操作了. 2.官方题解中更好的做法是,直接将每个数的十进制表示中的奇数改成1,偶数改成0,比如12345,然后把它看成二进制数10101,还原成十进制是2…

CF469 Codeforces Round #268 (Div. 2) http://codeforces.com/contest/469 开学了,时间少,水题就不写题解了,不水的题也不写这么详细了. A 水题 //#pragma comment(linker, "/STACK:102400000,102400000") #include<cstdio> #include<cmath> #include<iostream> #include<…

题目传送门 /* 贪心 + 模拟:首先,如果蜡烛的燃烧时间小于最少需要点燃的蜡烛数一定是-1(蜡烛是1秒点一支), num[g[i]]记录每个鬼访问时已点燃的蜡烛数,若不够,tmp为还需要的蜡烛数, 然后接下来的t秒需要的蜡烛都燃烧着,超过t秒,每减少一秒灭一支蜡烛,好!!! 详细解释:http://blog.csdn.net/kalilili/article/details/43412385 */ #include <cstdio> #include <algorithm> #i…

题目传送门 /* 题意:从前面找一个数字和末尾数字调换使得变成偶数且为最大 贪心:考虑两种情况:1. 有偶数且比末尾数字大(flag标记):2. 有偶数但都比末尾数字小(x位置标记) 仿照别人写的,再看自己的代码发现有清晰的思维是多重要 */ #include <cstdio> #include <iostream> #include <algorithm> #include <cmath> #include <cstring> #include…