Choosing Subsets with Maximum Weighted Average
نویسندگان
چکیده
Given a set of n real values, each with a positive weight, we wish to find the subset of n− k values having maximum weighted average. This is equivalent to the following form of parametric selection: given n objects with values decreasing linearly with time, find the time at which the n− k maximum values add to zero. We show that these problems can be solved in time O(n) (independent of k). A generalization in which weights are allowed to be negative is NP-complete.
منابع مشابه
Midpoints as average representations of pairs of descriptions by means of fuzzy subsets
Let d be a metric on the set FP(X) of fuzzy subsets of a set X. A midpoint of two fuzzy subsets μ, ν ∈ FP(X) is any fuzzy subset ξ ∈ FP(X) such that d(ξ, μ) = d(ξ, ν) = 1 2d(μ, ν). These midpoints can be used to describe “middle ways” or “compromises” between two situations described by the fuzzy subsets μ and ν. In this work we explicitly compute midpoints for weighted Hamming distances and fo...
متن کاملFuzzy-rough Information Gain Ratio Approach to Filter-wrapper Feature Selection
Feature selection for various applications has been carried out for many years in many different research areas. However, there is a trade-off between finding feature subsets with minimum length and increasing the classification accuracy. In this paper, a filter-wrapper feature selection approach based on fuzzy-rough gain ratio is proposed to tackle this problem. As a search strategy, a modifie...
متن کاملChoosing a Commercial Broiler Strain Based on Multicriteria Decision Analysis
With the complexity and amount of information in a wide variety of comparative performance reports in poultry production, making a decision is difficult. This problem is overcomed only when all data can be put into a common unit. For this purpose, five different decision making analysis approaches including Maximin, Equally likely, Weighted average, Ordered weighted averages and Technique for ...
متن کاملApproximate Weighted Farthest Neighbors and Minimum Dilation Stars
We provide an efficient reduction from the problem of querying approximate multiplicatively weighted farthest neighbors in a metric space to the unweighted problem. Combining our techniques with core-sets for approximate unweighted farthest neighbors, we show how to find (1+ ε)-approximate farthest neighbors in time O(logn) per query in D-dimensional Euclidean space for any constants D and ε. A...
متن کاملExact algorithms and applications for Tree-like Weighted Set Cover
We introduce an NP-complete special case of the Weighted Set Cover problem and show its fixed-parameter tractability with respect to the maximum subset size, a parameter that appears to be small in relevant applications. More precisely, in this practically relevant variant we require that the given collection C of subsets of a some base set S should be “tree-like.” That is, the subsets in C can...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- J. Algorithms
دوره 24 شماره
صفحات -
تاریخ انتشار 1997