3638：Moogle

题目描述

You got the original idea of making map software, called Moogle Maps, for the new cool Maple mPhone. It will even be capable of indicating the location of a house address like "Main Street 13". However, since the mPhone has limited storage capacity, you need to reduce the data amount. You don't want to store the exact location of every single house number. Instead only a subset of the house numbers will be stored exactly, and the others will be linearly interpolated. So you want to select house numbers that will minimise the average interpolation error, given how many house locations you have capacity to store. We view the street as a straight line, and you will always store the first and the last house location.

Given that you've stored the locations x_i and x_j for the houses with numbers i and j respectively, but no other house in between, the interpolated value for a house with number k with i < k < j is __poj_jax_start__x_i + (x_j - x_i) \times \frac{k-i}{j-i}__poj_jax_end__ $x_i + (x_j - x_i) \times \frac{k-i}{j-i}$ .

输入解释

The first line of input gives a single integer, 1 ≤ t ≤ 50, the number of test cases. For each test case, there are two lines. The first contains 2 ≤ h ≤ 200 and 2 ≤ c ≤ h, where h is the number of houses in the street and c is the number of house locations that can be stored. The second contains h integers in increasing order giving the location of the h houses. Each location is in the interval [0, 1000000].

输出解释

For each test case, output the average interpolation error over all the h houses for the optimal selection of c house locations to store. The output should be given with four decimal places, but we will accept inaccuracies of up to ±0.001.

输入样例

2
4 3
0 9 20 40
10 4
0 10 19 30 40 90 140 190 202 210

输出样例

0.2500
0.3000

该题目是Virtual Judge题目，来自北京大学POJ

题目来源 Nordic 2007

源链接： POJ-3638

最后修改于 2020-10-29T07:06:36+00:00 由爬虫自动更新

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通过率 --%

时间上限	内存上限
2000	65536