Anything related to disjoint sets, i.e. mathematical sets that have no element in common.
Anything related to disjoint sets, i.e. mathematical sets that have no element in common.
Questions tagged [disjoint-sets]
194 questions
0
votes
1 answer
Calculating the height of a Disjoint Set
Consider the program
for i from 1 to 60:
MakeSet(i)
for i from 1 to 30:
Union(i, 2*i)
for i from 1 to 20:
Union(i, 3*i)
for i from 1 to 12:
Union(i, 5*i)
for i from 1 to 60:
Find(i)
I would like to determine the height of the disjoint…
newUser
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- 2
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2 answers
In Disjoint Set Union (D.S.U.), why do we make the smaller sized subset as the child of the larger sized subset while performing the union operation?
I recently came across D.S.U. and its applications on the tree.As i was solving the related problems, I got Time Limit Exceeded error in some so i read the tutorial again and there I found that an improvised version of the normal union is…
Yash Verma
- 461
- 5
- 4
0
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1 answer
proof of time complexity of union find with path compression
The Wikipedia page: wikipedia page states that
If m operations, either Union or Find, are applied to n elements, the total run time is O(m log*n).
The detailed analysis arrived at this result is :
My questions are:
Shouldn't the sum be…
0
votes
1 answer
Disjoint set union implementation using c++
I am implementing Disjoint-Set Union by Rank and Path Compression in c++ according to the cp algorithm.But here I am getting an error reference to 'rank' is ambiguous . I have read many articles about this error but could not get any satisfactory…
user9857651
0
votes
1 answer
Interesting Python data structure problem involving disjoint sets, hashing, and graphs
Problem: You are planning an around-the-world trip with your two best friends for the
summer. There is a total of n cities that the three of you want to visit. As you are traveling around the world, you are
worried about time zones and airport…
0
votes
1 answer
How to calculate the maximum height of a tree in the resulting forest?
for i from 1 to 60:
MakeSet(i)
for i from 1 to 30:
Union(i, 2*i)
for i from 1 to 20:
Union(i, 3*i)
for i from 1 to 12:
Union(i, 5*i)
for i from 1 to 60:
Find(i)
Assume that the disjoint sets data structure is implemented as disjoint trees…
fds
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- 3
0
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1 answer
getting error when return value but correct ans when pass by reference
There are n kids, each of them is reading a unique book. At the end of any day, the i-th kid will give his book to the pi-th kid (in case of i=pi the kid will give his book to himself). It is guaranteed that all values of pi are distinct integers…
Aastha
- 41
- 8
0
votes
1 answer
Disjoint sets in Mongodb
Hi have a MongoDB collection matchedpairs with a data structure as follows:
each document defines a pairwise connection with each other, i.e 1 is in union with 2 and 2 is in union with 10 etc. There are a large number of relationships defined.
{
…
Neal Shail
- 61
- 5
0
votes
1 answer
How to select elements in a Quick union operation?
There are a set of elements S = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}. Here there are 10 elements (N = 10). An array arr to manage the connectivity of the elements. Arr[ ] that is indexed by elements of sets, which are of size N (as N elements in set),…
Kshitij Zutshi
- 69
- 7
0
votes
1 answer
Memory efficient version for the construction disjoint random lists
We have to positive integers b,n with b < n/2. We want to generate two random disjoint lists I1, I2 both with b elements from {0,1,...,n}. A simple way to do this is the following.
def disjoint_sets(bound,n):
import random
I1=[];I2=[];
L…
111
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0
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0 answers
Why second implementation is faster than the first one?
I recently tried to submit my solution for one of codeforces problem. I successfully solved the question and tried various test cases and the code was working correctly in my local machine. The time constraint was 2 seconds in the problem. I tried…
Roosh
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0
votes
1 answer
How to correctly implement wighted union and path compression in a UnionFind data structure
I am trying to implement a Union-Find/Disjoint-Set data structure in C, using weighted Union and path compression in Find. I have some questions as to how the weighted union should be implemented to reduce time complexity when compared to the non…
Desperados
- 434
- 5
- 13
0
votes
2 answers
Why is my Union Find Disjoint Sets algo for this problem not passing all test cases?
Sample input:
1
3 2
1 2
2 3
First line = # of test cases
First number of second line = number of people
Second number of second line = number of friendships, F
Following F lines = the friendships
Output would be the size of the largest friend…
J. Doe
- 85
- 1
- 6
0
votes
1 answer
In Java implementation of Kruskal's algorithm where exactly should we perform Path Compression?
While implementing Kruskal's algo in Java using Disjoint sets, should we call path-compression as separate funtion or it should be integral part of the find() funtion?
Don Sam
- 525
- 5
- 20
0
votes
2 answers
Problem while implementing Find() method for a disjoint set
Been trying to solve this for a while now. I've been given a Node in a Disjoint Set.The Node's implementation is as a class where either it has a different parent node or is it's own
class Node {
Node parent;
int rank;
//...constructor…
Vedant Pathak
- 31
- 4