All Questions
7 questions
5
votes
1
answer
255
views
Counting points above lines
Consider a set $P$ of $N$ points in the unit square and a set $L$ of $N$ non-vertical lines. Can we count the number of pairs $$\{(p,\ell)\in P\times L: p\; \text{lies above}\; \ell\}$$ in time $\...
- 121
6
votes
1
answer
424
views
Probability of intersecting a rectangle with random straight lines
We are given a rectangle $R$ with sides lengths $r_1$ and $r_2$, contained in a square $S$, with sides lengths $s_1=s_2\ge r_1$ and $s_2=s_1\ge r_2$. $R$ and $S$ are axis-aligned in a cartesian plane $...
- 1,677
2
votes
1
answer
270
views
Algorithm to compute the convex hull of a set of $m$ possibly intersecting convex polygons in the plane
I am trying to find an algorithm to compute the convex hull of a set of $m$ possibly intersecting convex polygons in the plane, with a total of $n$ vertices. Let $h$ denote the number of vertices on ...
4
votes
1
answer
519
views
A brief question about the "Eight Queens" Puzzle
The classical Eight Queens puzzle asks whether it is possible to arrange $ 8 $ queens on an $ 8 \times 8 $ chess board, so that no two queens attack each other.
It is well-known that such ...
- 151k
8
votes
3
answers
389
views
A simplified Art Gallery Problem in a matrix
Let's take a $m \times n$ matrix as an area with $m \times n$ blocks (likes a 2D-version of the world in Minecraft). We have to put some lamps in this matrix to illuminate the whole matrix. Here is ...
- 540
3
votes
2
answers
333
views
Combinatorial design for minimization problem over binary strings
Suppose the cost of a binary string $B$ of length $k$ is the number of $1$s that occur before the last $0$. For example, $1110$ has cost 3 while $0111$ has cost 0. Now suppose you can choose $k$ ...
- 19k
4
votes
1
answer
1k
views
Finding integer points on an N-d convex hull
Suppose we have a convex hull computed as the solution to a linear programming problem (via whatever method you want). Given this convex hull (and the inequalities that formed the convex hull) is ...
- 151k