0
votes
1answer
38 views

How to extract all the points from a noisy surface?

I have points representing a bridge like in this picture: My goal is to get all the points that are in the red box. These points all share a common surface that is not necessarily planar. The ...
2
votes
0answers
47 views

A* vs D* vs Dijkstra [closed]

I understand the basis of A* as being a derivative of Dijkstra, however, I recently found out about D*. From wikipedia, I can understand the algorithm. What I do not understand is why I would use D* ...
0
votes
0answers
285 views

Difference between breadth first search and iterative deepening depth first search

I knew until now, the graph search algorithms BFS and DFS. Today I had a lecture at the university and the professor introduced us to ID-DFS (Iterative deepening depth first search). However I find it ...
0
votes
0answers
40 views

How to search for an object in more efficient way?

I have a doubt how to check if structure contains an object. Simple sketch of my structure: Root - is a group which can contain groups, keys, values. Group - can contain groups keys, values. Key - ...
1
vote
1answer
248 views

Breadth-first search tree

It seems intuitive, and is actually proven in many books, that each path from starting vertex to another one in any search tree of a breadth-first algorithm is the shortest. However, I couldn't find ...
0
votes
1answer
412 views

Term-document vs document-term matrix [closed]

I am not sure if this is the right website to ask this question but I cant figure out where else to get the answer so, please, dont be mad :-) As my bachelor thesis/project, I am trying to construct ...
0
votes
1answer
41 views

Trivial case of $s \in T$

I was reading paper A Formal Basis for the Heuristics Determination of Minimum Cost Paths in section B "Some Definition About Graphs" there is footnote that say "We exclude the trivial case of $s \in ...
2
votes
1answer
1k views

Median of medians algorithm

I am referring to the algorithm presented here used to find a good pivot: http://en.wikipedia.org/wiki/Selection_algorithm#Linear_general_selection_algorithm_-_Median_of_Medians_algorithm My ...
0
votes
1answer
306 views

Help in understanding search of Vantage-Point tree

This is my reference: http://stevehanov.ca/blog/index.php?id=130 A vantage-point tree is a way of organizing a set of points so that finding the n-nearest neighbors is as efficient as possible. It ...
1
vote
1answer
713 views

What is the lower bound and upper bound on time for inserting n nodes into a binary search tree?

So given a $n$ array of few numbers(say $n$) we can sort them using the binary search tree (BST) as a black box . In order to that we first build a BST out of the array taking all the elements in ...
0
votes
1answer
115 views

Ranking System :S

My math experiences I had at school are not very advanced and I'm struggling with a calculation right now... I'm programming an image Search script for my company where you can find all pictures we ...
2
votes
1answer
1k views

What is the best strategy for a guess-my-number game?

In the "guess-my-number" game, one player (player A) makes guesses at another player's (player B) secret number. All games would follow the following procedure: Player B decides on a number between ...
7
votes
2answers
2k views

Algorithm wanted: Enumerate all subsets of a set in order of increasing sums

I'm looking for an algorithm but I don't quite know how to implement it. More importantly, I don't know what to google for. Even worse, I'm not sure it can be done in polynomial time. Given a set of ...
1
vote
1answer
142 views

Is there a simple function which can be used to determine the two “next” search indexes in a binary search?

Edit: question simplified to remove confusion Assuming a sorted list of items with indexes from 1 to N, and given only an index number ...
6
votes
3answers
4k views

Lower bound for finding second largest element

In a recent discussion, I came across the idea of proving a lower bound for the number of comparisons required to find the largest element in an array. The bound is $n - 1$. This is so because the set ...
12
votes
3answers
681 views

Twenty questions against a liar

Here's one that popped into my mind when I was thinking about binary search. I'm thinking of an integer between 1 and n. You have to guess my number. You win as soon as you guess the correct number. ...