Questions about algorithms that receive the input piecewise and have to make decisions, that is produce output, before having seen the whole input.

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1answer
23 views

Online and parallizeable set intersection algorithm

I have problem that is reducible to the following: From a collection of stacks, find all items whose "keys" are on all stacks. My current solution to this problem is to just pop things off as ...
4
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2answers
71 views

Lazily computing a random permutation of the positive integers

Are there any existing efficient algorithms for lazily computing a random permutation of the positive integers in a given range (e.g. the range offered by an unsigned integer type in a CPU)? What I ...
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1answer
26 views

Packing unsplittable flows problem

For a single stream of elements as input every elements should be routed into a fixed number of $k$ output streams trying to keep them balanced. In the following example $k=3$ : Let's define as ...
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0answers
24 views

Do online quantile estimation algorithms that support deletions exist?

There are several online quantile estimation algorithms, but I haven't seen any that supports deletions (i.e. unobserve elements observed in the past). Are there any such known algorithms? To ...
3
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1answer
179 views

An incrementally-condensed transitive-reduction of a DAG, with efficient reachability queries

Is there an incremental directed graph data structure that has the following properties: Keeps an internal graph structure as a DAG, and the graph is accessible (notwithstanding other helper ...
2
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0answers
188 views

Motion planning using second order Bézier curves

I'm trying to find an algorithm for a motion planning problem. I have $N$ points, $P_1$ to $P_N$, in $k$-dimensional cartesian space, defining $N-1$ segments. The problem is about constructing the ...
3
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0answers
56 views

Online algorithm for planning

Let S be a system whose state can be altered by performing actions. Each action has two possible outcomes, and each outcome brings to a specific system state. A ...
14
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1answer
162 views

Can a perceptron forget?

I would like to build an online web-based machine learning system, where users can continuously add classified samples, and have the model updated online. I would like to use a perceptron or a similar ...
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1answer
364 views

Load balancing. Why not use priority queues?

I have recently learned about various randomized algorithms for load balancing. The model is always that there are $m$ balls and $n$ bins and the balls arrive one at a time. The task is to minimize ...
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1answer
75 views

How to sample uniformly from a stream of elements, some of which are unsuited?

I get values $x_t$ in an online fashion and want to buy "good" ones, where "good" means that some measure $P(x_t) >T$. Consider the following simple algorithm. ...
9
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2answers
248 views

Fair cake-cutting when players join late

The usual statement of the fair cake-cutting problem assumes that all $n$ players get their share at the same time. However, in many cases the players arrive incrementally. For example, we may divide ...
16
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1answer
310 views

Weighted sum of last N numbers

Suppose we're receiving numbers in a stream. After each number is received, a weighted sum of the last $N$ numbers needs to be calculated, where the weights are always the same, but arbitrary. How ...
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2answers
393 views

Computing inverse matrix when an element changes

Given an $n \times n$ matrix $\mathbf{A}$. Let the inverse matrix of $\mathbf{A}$ be $\mathbf{A}^{-1}$ (that is, $\mathbf{A}\mathbf{A}^{-1} = \mathbf{I}$). Assume that one element in $\mathbf{A}$ is ...
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0answers
248 views

Streaming Knapsack Problem

I want to implement efficiently "streaming Knapsack" problem in java. The problem is I have a stream input of integer data coming continuously for example -1, 2, 9, 5, 5, 11, 1 -3,... The question ...
10
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3answers
738 views

Determine missing number in data stream

We receive a stream of $n-1$ pairwise different numbers from the set $\left\{1,\dots,n\right\}$. How can I determine the missing number with an algorithm that reads the stream once and uses a memory ...
3
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1answer
44 views

Block detection in repeated stream

I need to recover a data block from a repeated stream of data. I'm looking to see what algorithms may already exist for this as it does not feel like a novel situation. Here are the specifics: ...
4
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1answer
195 views

Online generation of uniform samples

A source provides a stream of items $x_1, x_2,\dots$ . At each step $n$ we want to save a random sample $S_n \subseteq \{ (x_i, i)|1 \le i \le n\}$ of size $k$, i.e. $S_n$ should be a uniformly chosen ...