dsaghjkye的博客

Rimi learned a new thing about integers, which is - any positive integer greater than 1 can be divided by its divisors. So, he is now playing with this property. He selects a number N. And he calls th...

Edward is the headmaster of Marjar University. He is enthusiastic about chess and often plays chess with his friends. What's more, he bought a large decorative chessboard with N rows and M columns.E...

题解：概率计数。因为是求期望值，考虑每个点对答案的贡献：对每个点是亮着的概率求和就是所求期望。那么每个点亮着的概率为多少呢？根据题意，对于点（x,y,z）只有当被选中的2个点（x1,y1,z1）,（x2,y2,z2），满足x1<=x<=x2且y1<=y<=y2且z1<=z<=z2时，该点的状态才会改变，因此对于每一维，在区间内的概率=1-区间在该点的...

 https://blog.youkuaiyun.com/qq_31759205/article/details/54710164题解：期望dp，设正确的门有a个，平均耗时为sum1，错误的门有b个，平均耗时为sum2。状态转移分2部分：①当i==k时，即已经记住k次走错的门，②当i<k时，#include<bits/stdc++.h>using namespace ...

You are in a contest, and unfortunately you don't have much time. You have one problem in hand; you just glanced at the sample output and found that it just wants 'YES' or 'NO'. So, you have made anot...

After being all out for 58 and 78 in two matches in the most prestigious tournament in the world, the coach of a certain national cricket team was very upset. He decided to make the batsmen practice a...

你正在玩你最喜欢的电子游戏，并且刚刚进入一个奖励关。在这个奖励关里，系统将依次随机抛出k次宝物，每次你都可以选择吃或者不吃（必须在抛出下一个宝物之前做出选择，且现在决定不吃的宝物以后也不能再吃）。宝物一共有n种，系统每次抛出这n种宝物的概率都相同且相互独立。也就是说，即使前k-1 次系统都抛出宝物1（这种情况是有可能出现的，尽管概率非常小），第k次抛出各个宝物的概率依然均为1/n。获取第 ...

Given a dice with n sides, you have to find the expected number of times you have to throw that dice to see all its faces at least once. Assume that the dice is fair, that means when you throw the dic...

Sometimes some mathematical results are hard to believe. One of the common problems is the birthday paradox. Suppose you are in a party where there are 23 people including you. What is the probability...

As Harry Potter series is over, Harry has no job. Since he wants to make quick money, (he wants everything quick!) so he decided to rob banks. He wants to make a calculated risk, and grab as much mone...

'Snakes and Ladders' or 'Shap-Ludu' is a game commonly played in Bangladesh. The game is so common that it would be tough to find a person who hasn't played it. But those who haven't played it (unluck...