Codeforces Round #678 (Div. 2) A. Reorder 题意:有一个有 n 个数的序列 a ,以及一个数 m ,问能否给序列a重新排序,能够满足式子 $\sum_{i=1}^{n}\sum_{j=1}^{n}\frac{a_{j}}{j}=m$. 思路:稍微计算一下便可以发现$1\times \frac{a_{1}}{1}+2\times \frac{a_{2}}{2}+...+n\times \frac{a_{n}}{n}=a_{1}+a_{2}+...+a_{n}…

比赛链接:https://codeforces.com/contest/1436 A. Reorder 题解 模拟一下这个二重循环发现每个位置数最终都只加了一次. 代码 #include <bits/stdc++.h> using namespace std; int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int t; cin >> t; while (t--) { int n, m; cin >>…

题意:有长度\(n\)的序列,让你构造序列,使得二分查找能在\(pos\)位置找到值\(x\).问最多能构造出多少种排列? 题解:题目给出的\(pos\)是固定的,所以我们可以根据图中所给的代码来进行二分,确定有多少数小于\(x\)和大于\(x\),然后根据排列组合即可算出答案. 代码: int n,x,pos; ll fac[N]; ll f[N],invf[N]; ll fpow(ll a,ll k){ ll res=1; while(k){ if(k&1) res=(res*a)%mod;…

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…