CF1776K.Uniform Chemistry
NOI/NOI+/CTSC
通过率:0%
时间限制:2.00s
内存限制:256MB
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题目描述
In a parallel universe there are n chemical elements, numbered from 1 to n. The element number n has not been discovered so far, and its discovery would be a pinnacle of research and would bring the person who does it eternal fame and the so-called SWERC prize.
There are m independent researchers, numbered from 1 to m, that are trying to discover it. Currently, the i-th researcher has a sample of the element si. Every year, each researcher independently does one fusion experiment. In a fusion experiment, if the researcher currently has a sample of element a, they produce a sample of an element b that is chosen uniformly at random between a+1 and n, and they lose the sample of element a. The elements discovered by different researchers or in different years are completely independent.
The first researcher to discover element n will get the SWERC prize. If several researchers discover the element in the same year, they all get the prize. For each i=1,2,…,m, you need to compute the probability that the i-th researcher wins the prize.
在一个平行宇宙中,存在 n 种化学元素,编号从 1 到 n。其中,编号为 n 的元素尚未被发现;它的发现将标志着科研的巅峰成就,并使发现者获得永恒的声誉以及所谓的 SWERC 奖。
共有 m 位彼此独立的研究员,编号从 1 到 m,他们正致力于发现该元素。目前,第 i 位研究员手中拥有一种元素 si 的样品。每年,每位研究员各自独立地进行一次聚变实验:若某研究员当前持有元素 a 的样品,则他在实验中会以等概率在区间 [a+1,n] 中随机选择一个整数 b,并由此生成元素 b 的样品,同时失去元素 a 的样品。不同研究员之间、或不同年份中所发现的元素完全相互独立。
首位发现元素 n 的研究员将独享 SWERC 奖;若多位研究员于同一年发现该元素,则他们共同获奖。对每个 i=1,2,…,m,你需要计算第 i 位研究员赢得该奖的概率。
输入格式
The first line contains two integers n and m (2≤n≤1018, 1≤m≤100) — the number of elements and the number of researchers.
The second line contains m integers s1,s2,…,sm (1≤si<n) — the elements that the researchers currently have.
第一行包含两个整数 n 和 m(2≤n≤1018,1≤m≤100)—— 分别表示元素总数和研究人员数量。
第二行包含 m 个整数 s1,s2,…,sm(1≤si<n)—— 表示研究人员当前拥有的元素。
输出格式
Print m floating-point numbers. The i-th number should be the probability that the i-th researcher wins the SWERC prize. Your answer is accepted if each number differs from the correct number by at most 10−8.
输出 m 个浮点数。其中第 i 个数应为第 i 位研究人员赢得 SWERC 奖项的概率。若每个数与正确答案的差值均不超过 10−8,则你的答案将被接受。
输入输出样例
输入#1
2 3 1 1 1
输出#1
1.0 1.0 1.0
输入#2
3 3 1 1 2
输出#2
0.5 0.5 1.0
输入#3
3 3 1 1 1
输出#3
0.625 0.625 0.625
输入#4
100 7 1 2 4 8 16 32 64
输出#4
0.178593469 0.179810455 0.182306771 0.187565366 0.199300430 0.229356322 0.348722518
说明/提示
In the first sample, all researchers will discover element 2 in the first year and win the SWERC prize.
In the second sample, the last researcher will definitely discover element 3 in the first year and win the SWERC prize. The first two researchers have a 50% chance of discovering element 2 and a 50% chance of discovering element 3, and only element 3 will bring them the prize.
In the third sample, each researcher has an independent 50% chance of discovering element 3 in the first year, in which case they definitely win the SWERC prize. Additionally, if they all discover element 2 in the first year, which is a 12.5% chance, then they will all discover element 3 in the second year and all win the prize.
在第一个样例中,所有研究人员都将在第一年发现元素 2,并赢得 SWERC 奖项。
在第二个样例中,最后一名研究人员必定在第一年发现元素 3,并赢得 SWERC 奖项。前两名研究人员各有 50% 的概率发现元素 2、50% 的概率发现元素 3,而只有发现元素 3 才能让他们获奖。
在第三个样例中,每名研究人员在第一年独立地以 50% 的概率发现元素 3,此时他们必定赢得 SWERC 奖项。此外,若他们全部在第一年发现元素 2(该事件发生的概率为 12.5%),则他们将在第二年全部发现元素 3,并全部获奖。
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