组合数,对数. 这道题要用到20w的组合数,如果直接相乘的话,会丢失很多精度,所以用去对数的方式实现. 注意指数,因为取完一次后,还要再取一次才能发现取完,所以是(n+1)次方. double 会爆掉,需要用long double 然后就是scanf和printf读入输出long doube会发生不可逆转的错误(dev-cpp),所以可以读入输出时候强制转换类型,或者用cin,cout(后者我感觉比较麻烦). #include<cstdio> #include<cstring> #…

今天来尝试了几道数学期望相关的题,这是我认为比较有趣的一道题 这次不废话啦直接开始~ 一句话题意:两个分别装有n个糖果的盒子,每次随机选一个盒子然后拿走一颗糖(选的概率分别是\(p\)和\((1-p)\)),直到有一次选了一个盒子打开之后发现没有糖果了,求另一个盒子糖果个数的期望值 \(n<=2*10^5\) 嗯首先我们得知道期望的线性性质:\(E(X+Y)=E(X)+E(Y)\) 如果我们假设最后打开的是第一个盒子,那么第二个盒子的糖果个数其实可能有\(0~n\)个,如果已经知道了有\(i\)…

There are N children standing in a line. Each child is assigned a rating value. You are giving candies to these children subjected to the following requirements: Each child must have at least one candy. Children with a higher rating get more candies…

There are N children standing in a line. Each child is assigned a rating value. You are giving candies to these children subjected to the following requirements: Each child must have at least one candy. Children with a higher rating get more candies…

135. Candy There are N children standing in a line. Each child is assigned a rating value. You are giving candies to these children subjected to the following requirements: Each child must have at least one candy. Children with a higher rating get mo…

Candy There are N children standing in a line. Each child is assigned a rating value. You are giving candies to these children subjected to the following requirements: Each child must have at least one candy. Children with a higher rating get more ca…

There are N children standing in a line. Each child is assigned a rating value. You are giving candies to these children subjected to the following requirements: Each child must have at least one candy. Children with a higher rating get more candies…

题目描述: There are N children standing in a line. Each child is assigned a rating value. You are giving candies to these children subjected to the following requirements: Each child must have at least one candy. Children with a higher rating get more ca…

C. Inna and Candy Boxes   Inna loves sweets very much. She has n closed present boxes lines up in a row in front of her. Each of these boxes contains either a candy (Dima's work) or nothing (Sereja's work). Let's assume that the boxes are numbered fr…

There are N children standing in a line. Each child is assigned a rating value. You are giving candies to these children subjected to the following requirements: Each child must have at least one candy. Children with a higher rating get more candies…