链接:http://codeforces.com/contest/454/problem/A A. Little Pony and Crystal Mine time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Twilight Sparkle once got a crystal from the Crystal Mine. A c…

Codeforces Round #713 (Div. 3) Editorial 记录一下自己写的前二题本人比较菜 A. Spy Detected! You are given an array a consisting of n (n≥3) positive integers. It is known that in this array, all the numbers except one are the same (for example, in the array [4,11,4,4]…

http://codeforces.com/contest/456/problem/A A. Laptops time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output One day Dima and Alex had an argument about the price and quality of laptops. Dima thi…

A:    http://codeforces.com/contest/1157/problem/A 题意:每次加到10的整数倍之后,去掉后面的0,问最多有多少种可能. #include <iostream> #include <algorithm> #include <vector> #include <string> #include <set> using namespace std; int main() { ios::sync_with…

A. Little Pony and Expected Maximum Time Limit: 1 Sec  Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/453/problem/A Description Twilight Sparkle was playing Ludo with her friends Rainbow Dash, Apple Jack and Flutter Shy. But she kept losing.…

A. Little Pony and Crystal Mine 水题,每行D的个数为1,3.......n-2,n,n-2,.....3,1,然后打印即可 #include <iostream> #include <vector> #include <algorithm> #include <string> using namespace std; int main(){ int n; cin >> n; vector<string>…

题目范围给的很小,所以有状压的方向. 我们是构造出一个数列,且数列中每两个数的最大公约数为1; 给的A[I]<=30,这是一个突破点. 可以发现B[I]中的数不会很大,要不然就不满足,所以B[I]<=60左右.构造DP方程DP[I][J]=MIN(DP[I][J],DP[I][J^C[K]]+abs(a[i]-k)); K为我们假设把这个数填进数组中的数.同时开相同空间记录位置,方便输出结果.. #include<iostream> #include<stdio.h>…

题目链接 题意 : 一个m面的骰子,掷n次,问得到最大值的期望. 思路 : 数学期望,离散时的公式是E(X) = X1*p(X1) + X2*p(X2) + …… + Xn*p(Xn) p(xi)的是所有最大值是xi的情况数/总情况数一共是m^n种,掷n次,所有最大值是xi的情况数应该是xi^n,但是这里边却包含着最大值非xi且不超过xi的种数,所以再减去最大值是xi-1或者最大值不超过这个的情况数.即sum += xi * (xi^n-(xi-1)^n)/m^n,但是这样求肯定是不行,因为m…

题目链接 题意:一个m个面的骰子,抛掷n次,求这n次里最大值的期望是多少.(看样例就知道) 分析: m个面抛n次的总的情况是m^n, 开始m==1时,只有一种 现在增加m = 2,  则这些情况是新增的那个的第一次的结果的后面最大的都是新增的, 之前的这些的分支也加上这个数,而且这个数是这一支里最大的,也就是说新增产生的结果 全都是m = 2的这个结果,所以用现在的总的情况减去之前的总的情况. 所以: 最大值是1: 1种 2: 2^n-1 3: 3^n-2^n ..... m: m^n-(m-1…

D. Little Pony and Harmony Chest   Princess Twilight went to Celestia and Luna's old castle to research the chest from the Elements of Harmony. A sequence of positive integers bi is harmony if and only if for every two elements of the sequence their…