Questions tagged [intervals]
The intervals tag has no usage guidance.
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1answer
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How to find the number of intervals containing a point when given a static set of intervals?
I've seen similar questions around here but I'm trying to address this problem with a slight change and maybe it makes it easier to solve.
I'm given a set of intervals $\{s_1,s_2,...,s_n\}$ where ...
3
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0answers
130 views
Count horizontal segments that intersect with a vertical segment
I have a set of $n$ horizontal line segments. I want to preprocess them and store them in a data structure, so that given a vertical segment $Q$ I can efficiently count the number of line segments ...
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1answer
44 views
Finding an interval in a binary search tree that contains a point
I have a binary search tree where nodes are non-overlapping intervals. I'm given a point, and I need to determine which interval the point belongs to (if any). This is easy to do because I can compare ...
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1answer
35 views
Proof for optimal interval scheduling using a Greedy Approach
You are given a set of n jobs, where each job j is associated with a size
s(how much time it takes to process the job) and a weight w(how important the
job is). Suppose you have only one machine ...
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2answers
71 views
Algorithm/data structure to quickly check if an integer is a member of any [lower, upper] interval
Are there any existing algorithms/strategies to test if an integer value is within the bounds of any of a list of intervals, where each interval is denoted by a [min, max] pair?
The naive approach is ...
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1answer
35 views
Matching schedules between users and providers
I have a problem I've been dealing for the past few days, and I'm pretty stuck.
Each user has a schedule for a given week, such as ...
2
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1answer
60 views
Minimal set of subintervals that 'covers' any subinterval in K subintervals
I have a big interval $I = [a, b]$ of size n.
I want an asymptotically minimal set of subintervals of $I$ (let's call it $S$) one can use to construct any subinterval of $I$, by concatenating at most ...
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0answers
35 views
Efficient data structure for multidimensional searching on intervals and keys
I am searching for a data structure that can capture a database, which is consisted of one column of intervals (like [0, 2], [4, 6]) and one/two columns of keys (...
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2answers
40 views
Sorted unsigned integer intervals tree structure
The goal is to store sorted unsigned integer intervals that can overlap only in the boundaries, e.g., |0–10|10–50|100–110|110–200|. This structure will be created ...
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0answers
34 views
Sort-of interval scheduling
The Problem
I have a set of sets of time intervals (hour, minute, day of the week). I want to select exactly one interval from each of set, and I want to minimize...
the number of pairwise ...
2
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1answer
45 views
Data Structures - Segment Trees
I was learning about segment trees and came across this:
We have an array arr[0 . . . n-1]. We should be able to
1 Find the sum of elements from index l to r where 0 <= l <= r <= n-1
...
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0answers
42 views
(M)ILP overlap of two intervals
I got an ILP Model where $c_i$ represents the starting time for a visit$_i$.
$c_i$ is already constraint by a number of constraints, one is $c_i > 0$.
I have now outside of my model 0 or multiple ...
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1answer
172 views
interval scheduling algorithm
can any one explain why the greedy algorithm solution i.e sorting according to finishing time is optimal in the interval scheduling algorithm ?? I want proof in layman's language. I was watching this ...
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1answer
53 views
Variant of interval scheduling with varying task durations
I am probably just missing the correct term for my problem to find the solution but here it goes:
I have a set of tasks with a given duration and an interval for each task in which it has to be ...
2
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1answer
19 views
Array of overlaping ranges
Consider that I have an array of ranges and I want to transform it to the new array that represents the ranges that any range is in.
Example:
Ranges:
[red: [1,11], black: [15,16],yellow: [5,9], ...
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0answers
44 views
Compile-time error control vs. interval arithmetic?
I use interval arithmetic for reliable computing. Now, a procedure coded in a good implementation of interval arithmetic takes perhaps about eight times as much as the same procedure carried out ...
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1answer
53 views
Candy Problem for k size window
I was solving this problem and end up learning two ways to solve this problem. One is two pass method and the other is considering peak and valleys (candies - interviewstreet). Both of these are O(n) ...
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0answers
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Segment-tree construction: do we recurse into both children?
This question is about segment-tree as described in this Wikipedia article.
When constructing the tree (inserting the new input-interval), if the input-interval doesn't contain the node-interval we ...
0
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1answer
23 views
Interval Scheduling Confusion
I am reading some notes about interval scheduling. I gives the following diagram:
and states that:
r2 is compatible with r3, while r2 and r1 are conflicting. Similarly, the set {r1, r3, r4} is ...
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1answer
18 views
Find longest interval if the intervals can propagate from one to another
Let's say we have given $n$ points on the x-axis, each point described with two integers: $x_i, a_i$, $x_i$ meaning it's position on the x-axis, and $a_i$ meaning that it can activate all the points ...
1
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1answer
226 views
Finding the longest overlapping interval pair
Say I have a list of $n$ integral intervals $[a,b]$ where each represents a set $S = \{a, a+1, \ldots, b\}$. An overlap is defined as $|S_1 \cap S_2|$. Example: $[3,6]$ and $[5,9]$ overlap on $[5,6]$ ...
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0answers
134 views
Construct polygons from axis-aligned intervals
Scenario
Consider one or more curved shapes in 2D space, clipped to a rectangular viewport. For example:
Unfortunately, data that would describe these shapes precisely, is not available.
Input data
...
2
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1answer
43 views
Can we find size of total interval in O(N)
Let's say we have given $N$ intervals in the form $[x, y]$, both $x,y$ are integers , we want to find the number of integers covered by at least one interval of all $N$ intervals, (look in the ...
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1answer
158 views
Obtain data structure able to do reverse range updates
For given array $A$ of size $N$, note that the array is going to be permutation of the numbers from 1 to N, each number will be there exactly once, we want to obtain data structure being able to ...
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1answer
130 views
Computing overlap of intervals in an integer programming framework
Suppose I have 2 intervals C1 = [x1, x2] and C2 = [y1, y2], where x1,x2,y1,y2 are variables in an Integer program, I want to compute the overlap of C1 and C2. I am interested in a tight formulation ...
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1answer
52 views
Check if current interval is overlapping some intervals, or is being overlapped
Let's say we have array of $K$ integers, and we have given $N$ intervals in the form $l_{i}, r_{i}$, both inclusive, the interval $i$ means that all elements in the range $[l_i, r_i]$ are covered. Our ...
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1answer
382 views
Troubles understanding this Interval Scheduling question
Can someone explain how to prove what this question is asking? I'm terrible at proofs and the fact that I don't even understand the hint is very troubling. This is a homework question.
Consider the ...
2
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1answer
72 views
how to prove original intervals and canonical form of intervals have the same interval graph
According to this paper,a family of intervals is said to be canonical if the coordinates of the endpoints of the intervals are distinct integers between 1 and 2n where n is the number of intervals.
...
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1answer
82 views
Compute lebesgue measure of set of intervals
Let $S = \{ [x_1, y_1], [x_2, y_2], \dots, [x_n, y_n] \}$ be a set of not necessarily disjoint intervals on $\mathbb{R}$. Is there an efficient way to compute the lebesgue measure of the union
$\...
2
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2answers
133 views
Canonical representation of finite maps on non-overlapping finite rational intervals
I would like to have a canonical representation of a map from rational intervals (f, t] with f, t ∈ ℚ to some irrelevant value type. These intervals are non-overlapping and there exist only finitely ...
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1answer
721 views
Find all intervals that are contained in a query interval
Given a set of intervals $S = I_1, ..., I_n$, what is the fastest way to find all intervals of $S$ that are completely contained in an interval $I_\text{query}$? It should also support incremental (...
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1answer
154 views
Check whether an interval is contained in a union of intervals
Initial Problem:
Given an interval $[A, B]$ and a set of intervals $S = \{[S_{11},
S_{12}], [S_{21}, S_{22}], [S_{31}, S_{32}], \ldots, [S_{N1}, S_{N2}]\}$
with $S_{11}\leq S_{21}\leq \cdots \leq ...
2
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1answer
199 views
Are IEEE floating point numbers intervals or point values?
The context is IEEE 754-2008 floating point number systems. The systems defined by the standard comprise, as far as I understand it, a bit-level representation and a set of guarantees on the precision ...
2
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2answers
1k views
Interval tree: find all intervals containing a given interval
Given an interval tree $T$ and an interval $I$, I need to find an algorithm that returns all intervals in $T$ that contain $I$. The asymptotic running time should be $O(min(n,(k + 1) log n))$ where $k$...
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vote
1answer
530 views
Interrupts and polling
Are Interrupts really just an abstracted form of polling?
I saw a system-file-watcher library that stated it used polling, as opposed to listening for events. Is the .NET framework SystemFileWatcher ...
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1answer
2k views
Find longest overlapping interval
Given a set $S$ of $n$ overlapping intervals, where each interval is in the range of [1..O(n)], preprocess $S$ so we can efficiently answer the following query:
Given an interval [i,j] output the ...
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2answers
1k views
Find minimum number of time points that cross out all intervals
Say we have a set of time intervals, that may intersect. A time point "marks" all of the intervals that are still unfinished at that time point. I wish to find an algorithm so that I can mark all of ...
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0answers
283 views
Interval scheduling, unclear greedy proof
I am having trouble understanding the proof of the theorem, which states that the greedy scheduling algorithm produces solutions of maximum size for the scheduling problem.
The proof that I am ...
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3answers
1k views
How many range are completely inside a given range
I have a list of ranges ai , bi. And I have many queries in the form of a range c, d, which asks how many ranges ( ai, bi ) are completely inside c, d.
c <= ai & bi <= d
There are so ...
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0answers
121 views
Interval scheduling with choice of interval per job
Interval Scheduling problems present several intervals that may overlap and the usual goal is to find the greater set of non overlapping intervals.
Variations of the problem on wikipedia and such add ...
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0answers
1k views
Why is it necessary to sort according to the starting time in the interval partitioning problem?
What is the problem if we sort the intervals according to their finishing time like the interval scheduling problem? Could someone give a counterexample
?
Note- (refer here for detailed definition)
...
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524 views
Some confusion about segment tree and line sweep method for finding area of union of axis parallel rectangles
I am having some confusion about finding the area of union of $n$ axis parallel rectangles in $O(n\log n)$ by the line sweep method. The following pictures are from the book of Shamos and Preparata.
...
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2answers
165 views
Efficient immutable data structure for small multi-sets of integer ranges?
Background
I'm currently writing some Elixir algorithms that are quite computationally expensive. The most-used datastructure is a multi-set of (finite) integer ranges. Modifying this data structure ...
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1answer
159 views
Efficiently locating the maximum value in interval over large amounts of data points
I have a set of $n$ two-dimensional data points $(x_i,y_i)$. I want to efficiently answer the following query: Given an arbitrary interval of $x$-values, find the highest and lowest points within ...
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1answer
273 views
Delete a consecutive range of leaves from a binary tree
Suppose I have a binary tree containing $n$ leaves and whose depth is $d$, where the data is in the leaves (the internal nodes don't hold data values).
I want to delete a consecutive interval of ...
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1answer
1k views
Data structure for set of intervals - query for all intervals contains given point
We're given a set of $n$ intervals $[a_i, b_i]$, $i=1...n$.
I am looking for a data structure which makes it possible to query for all intervals that contain the point $x$.
My proposition is using ...
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0answers
51 views
Given $m$ operations of coloring. What is color of $i$-th ball ?
There are given $n$ balls. Their indexes: $\{1,...,n\}$.
Initially all of them are painted in $green$. (other possible color in my problem is $red$).
It is possible to paint interval of balls in color ...
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1answer
2k views
Interval scheduling scheduling problem with minimal workers
I am writing a greedy algorithm for a variation of the interval scheduling problem that I haven't seen before.
I have a set of jobs, each with start and finish time. All jobs in set must be assigned ...
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2answers
2k views
Algorithm: ordering non-overlapping intervals
Assume we have a (multi)set of nontrivial intervals $\mathcal{I} = \{I_1,...,I_n\}$ and for any two $I_i, I_j \in \mathcal{I}$, we have that $I_i \cap I_j$ is trivial (that is: contains at most one ...
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1answer
5k views
Time Complexity proof for Segment Tree implementation of the ranged sum problem
I understand that segment trees can be used to find the sum of sub array of $A$. And that this can done in $\mathcal{O}(\log n)$ time according to the tutorial here.
However I'm not able to prove ...
