随笔分类 - DP----概率DP
1
摘要：Valera is a coder. Recently he wrote a funny program. The pseudo code for this program is given below: Now Valera wonders: given the values x, k and p
阅读全文
摘要：A .Assignments 题意：给定距离D，以及N个飞机的速度Vi，单位时间耗油量Fi，总油量Ci。问有多少飞机可以到达目的地。 思路：即问多少飞机满足(Ci/Fi)*Vi>=D > Ci*Vi>=Fi*D; #include<bits/stdc++.h> #define ll long lon
阅读全文
摘要：Description 小Q同学现在沉迷炉石传说不能自拔。他发现一张名为克苏恩的牌很不公平。如果你不玩炉石传说，不必担心，小Q 同学会告诉你所有相关的细节。炉石传说是这样的一个游戏，每个玩家拥有一个 30 点血量的英雄，并且可以用牌 召唤至多 7 个随从帮助玩家攻击对手，其中每个随从也拥有自己的血量
阅读全文
摘要：题意：长度为n的排列，m次交换xi, yi，每个交换x，y有50%的概率不发生，问逆序数的期望 。n, m <= 1000 思路：我们只用维护大小关系，dp[i][j]表示位置i的数比位置j的数大的概率。 那么每次交换x和y。 假设x<y，那么区间就有三种: [1,x-1]，[x+1,y-1]， [
阅读全文
摘要：Description osu 是一款群众喜闻乐见的休闲软件。 我们可以把osu的规则简化与改编成以下的样子: 一共有n次操作，每次操作只有成功与失败之分，成功对应1，失败对应0，n次操作对应为1个长度为n的01串。在这个串中连续的 X个1可以贡献X^3 的分数，这x个1不能被其他连续的1所包含（也
阅读全文
摘要：There is a robot on the 2D plane. Robot initially standing on the position (0, 0). Robot can make a 4 different moves: After moving N times Robot gets
阅读全文
摘要：描述 一日，崔克茜来到小马镇表演魔法。 其中有一个节目是开锁咒：舞台上有 n 个盒子，每个盒子中有一把钥匙，对于每个盒子而言有且仅有一把钥匙能打开它。初始时，崔克茜将会随机地选择 k 个盒子用魔法将它们打开。崔克茜想知道最后所有盒子都被打开的概率，你能帮助她回答这个问题吗？ 输入 第一行一个整数 T
阅读全文
摘要：数学期望 P=Σ每一种状态*对应的概率。 因为不可能枚举完所有的状态，有时也不可能枚举完，比如抛硬币，有可能一直是正面，etc。在没有接触数学期望时看到数学期望的题可能会觉得很阔怕（因为我高中就是这么认为的，对不起何老板了QwQ），避之不及。 但是现在发现大多数题就是手动找公式或者DP推出即可，只要
阅读全文
摘要：Organizing a programming contest is not an easy job. To avoid making the problems too difficult, the organizer usually expect the contest result satis
阅读全文
摘要：King Arthur is an narcissist who intends to spare no coins to celebrate his coming K-th birthday. The luxurious celebration will start on his birthday
阅读全文
摘要：495. Kids and Prizes Time limit per test: 0.25 second(s) Memory limit: 262144 kilobytes input: standard output: standard ICPC (International Cardboard
阅读全文
摘要：The dragon and the princess are arguing about what to do on the New Year's Eve. The dragon suggests flying to the mountains to watch fairies dancing i
阅读全文
摘要：BuggyD loves to carry his favorite die around. Perhaps you wonder why it's his favorite? Well, his die is magical and can be transformed into an N-sid
阅读全文
摘要：In 0th day, there are n-1 people and 1 bloodsucker. Every day, two and only two of them meet. Nothing will happen if they are of the same species, tha
阅读全文
摘要：Akemi Homura is a Mahou Shoujo (Puella Magi/Magical Girl). Homura wants to help her friend Madoka save the world. But because of the plot of the Boss
阅读全文
摘要：When wake up, lxhgww find himself in a huge maze. The maze consisted by N rooms and tunnels connecting these rooms. Each pair of rooms is connected by
阅读全文
摘要：Background If thou doest well, shalt thou not be accepted? and if thou doest not well, sin lieth at the door. And unto thee shall be his desire, and t
阅读全文
摘要：问题： Ivan is fond of collecting. Unlike other people who collect post stamps, coins or other material stuff, he collects software bugs. When Ivan gets
阅读全文
摘要：时间限制:10000ms 单点时限:1000ms 内存限制:256MB 时间限制:10000ms 单点时限:1000ms 内存限制:256MB 描述 What is possibility of rolling N dice and the sum of the numbers equals to
阅读全文
摘要：描述 大家对斐波那契数列想必都很熟悉: a0 = 1, a1 = 1, ai = ai-1 + ai-2,(i > 1)。 现在考虑如下生成的斐波那契数列: a0 = 1, ai = aj + ak, i > 0, j, k从[0, i-1]的整数中随机选出（j和k独立）。 现在给定n，要求求出E(
阅读全文
1
