Questions tagged [prims-algorithm]
Prim's algorithm is a greedy algorithm which forms minimum spanning tree for the given graph. During execution, Prim's algorithm grows single tree by adding edges to it, unlike Kruskal's algorithm in which there can be multiple minimum spanning trees during execution.
22
questions
1
vote
1
answer
237
views
Find MST with bounded edge weight in O(|V|+|E|)
I need to describe (even in words) an algorithm that gets a connected, undirected, weighted graph so that the weight of each edge is either 1,2 or 3; and returns MST of that graph is time complexity O(...
- 25
1
vote
1
answer
252
views
Why Prim algorithm may fail to return minimum spanning forest on disconnected undirected graph
I am trying to address the following claim- "running prim algorithm on a disconnected undirected graph returns minimum spanning forest".
I thing that the claim may be false (i.e there might ...
- 25
1
vote
1
answer
161
views
MST with weights in {1, 2, 3, 4, 5}
I am given an undirected connected graph with $n$ nodes, average degree $\sqrt{\log n}$, and each edge having integer weight in $\{1,..,5\}$. I am asked to describe MST algorithm which is as efficient ...
- 159
1
vote
0
answers
21
views
How to find if there's an MST where vertex $v$ has degree 2 in it? [duplicate]
I've faced this question and I hope that someone can help with it.
Question: We're given an undirected graph $G=(V,E,w)$ where $w\colon E\rightarrow \mathbb{Q}$ and vertex $v$. We want to find if ...
- 453
4
votes
2
answers
526
views
Why do basic graph algorithms (BFS, DFS, Prim, Kruskal) have a similar structure?
This is my first post on CS Stack Exchange. For some time, I have been studying basic graph algorithms, mainly BFS, DFS, minimum spanning trees and their basic algorithms (Kruskal and Prim). One thing ...
- 43
2
votes
0
answers
70
views
Minimum unrooted binary spanning tree
Given a graph $G$ with $n$ tip vertices, $n-2$ internal vertices, and a cost on each edge $C(v)$, find a minimum spanning tree subject to degree constraints:
tips have a degree of $1$
internal ...
- 121
2
votes
0
answers
409
views
The Cut Lemma for graphs with non-distinct edges
In my introductory algorithms class I recently learned about the Cut Lemma and how it can be used to prove correctness for many Minimum Spanning Tree algorithms like Kruskal's and Prim's.
In class, to ...
- 47
1
vote
1
answer
293
views
Find MST on grid graph with only weight of 1 and 2 in $O(|V|+|E|)$
Given a grid graph $G=(V,E)$ which has only two different integer costs/weights of 1 and 2. Find Minimum Spanning Tree in $O(|V|+|E|)$.
I tried the following:
Changing Kruskal using a counting Sort ...
- 163
0
votes
1
answer
732
views
Best algorithm (Time Complexity) to find Minimum spanning tree of an complete, positive weighted, undirected, graph
Suppose that we have a complete undirected positive weighted graph $G = \langle V, E\rangle$. What is the most efficient algorithm, in terms of time complexity, to find an MST for $G$?
The best prime ...
0
votes
0
answers
92
views
Improve Prim's algorithm runtime
Assume we run Prim’s algorithm when we know all the weights are
integers in the range {1, ...W} for W, which is logarithmic in |V|. Can you improve Prim’s running time?
When saying 'Improving', it ...
- 1
1
vote
1
answer
77
views
Minimum Spanning Tree with one particular edge minimised(continued)
I have recently encountered a coding problem, specifically, the CCC problem S4.
In the problem, it states that you are given a spanning tree, or otherwise a "valid plan of pipes", that connect each ...
- 147
1
vote
2
answers
419
views
Minimum spanning tree such that one edge can be minimised
During a computer coding exam, I have encountered such a problem.
Given a list of vertexes and edges between the vertexes,and a positive number, D, what is the minimum spanning tree between the ...
- 147
3
votes
3
answers
1k
views
MST: Is there such an example of a graph with unique mst and not unique light edge?
The problem is the following:
Give an example of a graph that has a unique minimum spanning tree but for every cut of the graph, there is not a unique light edge crossing the cut.
I am trying to ...
- 33
1
vote
2
answers
591
views
Why the time complexity of Prim's algorithm is not $|V||E|lg|V|$ but $|E|lg|V|$?
In the CLRS, time complexity of Prim's algorithm is $O(|V|lg|V|+|E|lg|V|)=O(|E|lg|V|)$.
But, for my understanding, Prim's algorithm iterates $|E|$ times for DECREASE-KEY operation which takes $O(lg|V|...
- 353
1
vote
1
answer
6k
views
Minimum spanning tree - Prim's algorithm
I have to demonstrate Prim's algorithm for an assignment and I'm surprised that I found two different solutions, with different MSTs as an outcome. Now I now that shouldn't happen, so I wonder what I ...
- 113
1
vote
0
answers
145
views
n'th cheapest MST in a graph, with multiple edges that can have the same weight
I'm trying to think about an algorithm for this problem.
I know there is an algorithm for the second cheapest MST in a graph, but
if I understood it correctly it only solves cases in which every ...
- 29
1
vote
2
answers
8k
views
Time complexity of Prim's algorithm
There is this Prim's algorithm I am studying, the time complexity of which is $O(n^2)$ (in the adjacency matrix).
As far as I have understood,that is because we have to ckeck all the nodes per every ...
- 609
3
votes
1
answer
2k
views
MST for a finite number of weights
Let $F$ be a finite set of real numbers say $\{w_1,\dots,w_k\}$.
Let $G=(V,E)$ be an undirected connected graph and let $w\colon E\to F$ be a weight function.
Describe a linear time algorithm that ...
- 722
3
votes
2
answers
458
views
Minimum path - robot motion problem combined with freeze tag problem
Alright, I am not entirely sure if this is the right place to ask this, but here goes:
I have a map of coordinates of robots and obstacles. The first robot is awake from the start of the problem and ...
1
vote
1
answer
828
views
Prim's algorithm on graph with weights of only $1$ and $2$ on each edge
I have this version of Prim's algorithm
Prim$(G=(V,E),s\in V,w)\\
1.\ d(s)\leftarrow 0;\forall u \neq s:d(u)\leftarrow \infty\quad \color{red}{O(|V|)}\\
2.\ \forall u \in V:p(u)\leftarrow \text{...
- 211
9
votes
2
answers
8k
views
Finding MST after adding a new vertex
Let $G=(V,E)$ which is undirected and simple. We also have $T$, an MST of $G$. We add a vertex $v$ to the graph and connect it with weighted edges to some of the vertices. Find a new MST for the new ...
- 203
3
votes
4
answers
4k
views
