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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3
votes
1answer
25 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 ...
2
votes
0answers
21 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
votes
1answer
159 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
votes
0answers
168 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
votes
0answers
52 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
votes
1answer
148 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 ...
1
vote
1answer
280 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 ...
1
vote
1answer
67 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
votes
2answers
215 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
votes
1answer
293 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 ...
13
votes
2answers
302 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 ...
1
vote
0answers
216 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
votes
3answers
649 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
votes
1answer
41 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
votes
1answer
168 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 ...