【题解】Solution Set - NOIP2024集训Day26 概率期望 dp

合集 - Solution Set(47)

1.【题解】Solution Set - 树论2024-07-202.【题解】Solution Set - 容斥原理/二项式反演2024-07-203.【题解】Solution Set - 杂题选讲「刘君实」2024-07-254.【题解】Solution Set - 新高一矩阵选讲「陶治霖」2024-08-065.【题解】Solution Set - NOIP2024集训Day1 数据结构2024-08-076.【题解】Solution Set - NOIP2024集训Day2 线段树2024-08-087.【题解】Solution Set - NOIP2024集训Day3 权值线段树、动态开点、主席树2024-08-098.【题解】Solution Set - NOIP2024集训Day5 扫描线2024-08-129.【题解】Solution Set - NOIP2024集训Day7 线段树分裂与合并、平衡树2024-08-1410.【题解】Solution Set - NOIP2024集训Day8 并查集和可持久化并查集2024-08-1511.【题解】Solution Set - NOIP2024模拟赛22024-08-1812.【题解】Solution Set - NOIP2024集训Day10 树的直径、重⼼、中⼼2024-08-1913.【题解】Solution Set - NOIP2024集训Day9 树上问题2024-08-1614.【题解】Solution Set - NOIP2024集训Day12 树上启发式合并2024-08-2115.【题解】Solution Set - NOIP2024集训Day13 点分治、点分树2024-08-2216.【题解】Solution Set - NOIP2024集训Day14 CDQ分治2024-08-2317.【题解】Solution Set - NOIP2024集训Day17 整体二分2024-08-2918.【题解】Solution Set - NOIP2024集训Day18 优化建图2024-08-3019.【题解】Solution Set - NOIP2024模拟赛42024-09-0120.【题解】Solution Set - NOIP2024集训Day20 DP常⻅模型1「序列」2024-09-0221.【题解】Solution Set - NOIP2024集训Day21 DP常⻅模型2「背包」2024-09-0322.【题解】Solution Set - NOIP2024集训Day22 DP常⻅模型 1「序列」& 2「背包」2024-09-0423.【题解】Solution Set - NOIP2024集训Day23 DP常⻅模型3「区间」2024-09-0524.【题解】Solution Set - NOIP2024集训Day24 DP常⻅模型3「区间」2024-09-06

25.【题解】Solution Set - NOIP2024集训Day26 概率期望 dp2024-09-09

26.【题解】Solution Set - NOIP2024集训Day27 dp2024-09-1027.【题解】Solution Set - NOIP2024集训Day28 树形 dp2024-09-1228.【题解】Solution Set - NOIP2024集训Day32 数位 dp2024-09-1929.【题解】Solution Set - NOIP2024集训Day36 dp 优化 - 状态设计2024-09-2330.【题解】Solution Set - NOIP2024集训Day37 计数 dp2024-09-2931.【题解】Solution Set - NOIP2024集训Day43 博弈论2024-10-0432.【题解】Solution Set - NOIP2024集训Day44-45 图论2024-10-0533.【题解】Solution Set - NOIP2024集训Day47 最小生成树2024-10-0834.【题解】Solution Set - NOIP2024集训Day50 图的连通性相关2024-10-1435.【题解】Solution Set - NOIP2024集训Day52 图论杂题2024-10-1536.【题解】Solution Set - NOIP2024集训Day53 图论杂题22024-10-1537.【题解】Solution Set - NOIP2024集训Day55 图论杂题32024-10-1738.【题解】Solution Set - NOIP2024集训Day56 2-sat & 哈希2024-10-1839.【题解】Solution Set - NOIP2024集训Day57 字符串 hash2024-10-2140.【题解】Solution Set - NOIP2024集训Day58 字符串2024-10-2241.【题解】Solution Set - NOIP2024集训Day60 数学2024-10-2442.【题解】Solution Set - NOIP2024集训Day62 贪心2024-10-2843.【题解】Solution Set - NOIP2024集训Day63 贪心2024-10-3144.【题解】Solution Set - NOIP2024集训Day71 贪心2024-11-0745.【题解】Solution Set - NOIP2024集训Day77 反悔贪心2024-11-1446.【题解】Solution Set - NOIP2024集训Day83 dp2024-11-2147.【题解】Solution Set - NOIP2024集训Day87 二分 & 杂题2024-11-25

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【题解】Solution Set - NOIP2024集训Day26 概率期望 dp

https://www.becoder.com.cn/contest/5515

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「QOJ2606」Gachapon

$f_{i,j}$：用一次合法的 level-i rolling 能够抽到的 $j$ 的期望个数。

$h_{i,j,k}$：在 $i$ 次操作之内，抽到恰好 $k$ 个 $j$ 的概率。

$$\begin{gathered} h_{i,j,k}=\sum _{l=k}^i(\genfrac{}{}{0ex}{}{l}{k})(-1{)}^{l-k}(\genfrac{}{}{0ex}{}{l}{k})P(j) \\ {f}_{i,j}=\sum _{k=0}^{b_k}{h}_{b_k,j,k} \end{gathered}$$

（26min passed...（$f$ 的转移还是推不出来。

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对于条件概率 $P(a\mid b)\cdot P(b)=P(b\mid a)\cdot P(a)$

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「QOJ8526」Polygon II

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「UOJ884」509 号迷宫

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「CF1210G」Mateusz and Escape Room