CF1826F.Fading into Fog
省选/NOI-
通过率:0%
时间限制:4.00s
内存限制:256MB
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题目描述
This is an interactive problem.
There are n distinct hidden points with real coordinates on a two-dimensional Euclidean plane. In one query, you can ask some line ax+by+c=0 and get the projections of all n points to this line in some order. The given projections are not exact, please read the interaction section for more clarity.
Using the minimum number of queries, guess all n points and output them in some order. Here minimality means the minimum number of queries required to solve any possible test case with n points.
The hidden points are fixed in advance and do not change throughout the interaction. In other words, the interactor is not adaptive.
A projection of point A to line ax+by+c=0 is the point on the line closest to A.
这是一个交互式问题。
平面上预先固定了 n 个互不相同的隐藏点,其坐标为实数。每次查询中,你可以指定一条直线 ax+by+c=0,系统将返回这 n 个点在该直线上的投影(以某种顺序给出)。注意:所给的投影并非精确值,请参阅“交互说明”部分以获得更清晰的解释。
你需要用尽可能少的查询次数,猜出全部 n 个点的坐标,并以任意顺序输出它们。此处“最少查询次数”是指:对任意含 n 个点的合法测试用例,均能保证求解成功的最小查询数。
所有隐藏点在交互开始前即已固定,且在整个交互过程中保持不变。换言之,交互器是非自适应的(non-adaptive)。
点 A 到直线 ax+by+c=0 的投影,定义为该直线上距离 A 最近的点。
输入格式
The first line contains a single integer t (1≤t≤50) — the number of test cases.
The description of the test cases follows.
The first line of each test case contains a single integer n (2≤n≤25) — the number of hidden points.
For each test case, it is guaranteed that for any pair of hidden points, their x coordinates differ by at least 1. Analogously, y coordinates of any pair also differ by at least 1.
Coordinates x and y of all hidden points do not exceed 100 by absolute value.
第一行包含一个整数 t(1≤t≤50)—— 测试用例的数量。
接下来是测试用例的描述。
每个测试用例的第一行包含一个整数 n(2≤n≤25)—— 隐藏点的数量。
对于每个测试用例,保证任意两个隐藏点的 x 坐标之差的绝对值至少为 1;同理,任意两个隐藏点的 y 坐标之差的绝对值也至少为 1。
所有隐藏点的坐标 x 和 y 的绝对值均不超过 100。
输入输出样例
输入#1
1 2 1 1 2.5 1 1.500000001 1.500000000 2 2
输出#1
? 0 1 -1 ? 0.2 -0.2 0 ! 1 3 2.5 0.500000001
说明/提示
In the sample the hidden points are (1,3) and (2.5,0.5)
A picture, which describes the first query:

A picture, which describes the second query:

在样例中,隐藏的点为 (1,3) 和 (2.5,0.5)。
描述第一次查询的图片:

描述第二次查询的图片:

输入解题思路,AI测评打分。不知道怎么写?