How to connect 2 vertexes in an Adjacency List?
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0
down vote
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I'm trying to learn different Data Structures and I'm currently struggling on Graphs.
I am trying to implement an Adjacency List using a Map of Linked Lists. This lets me be able to search up the name of the vertex and see all its connections quickly.
But I am having trouble actually adding any connections. What I'm currently doing is
public void add(V vertexName) {
if (!contains(vertexName)) {
ArrayList<V> array = new ArrayList<>();
adjList.put(vertexName,array);
}
}
public void connect(V start, V destination) {
if (!contains(start) || !contains(destination))
throw new NoSuchElementException();
adjList.get(start).add(destination); //adds destination to starts arraylist
}
System.out.print(adjList.toString);
But, for example, if I add 12, 10, and 20 to my list and then connect 20 and 12, I still just get:
12
10
20
instead of
12
10
20 - > 12
Any tips would be much appreciated. If it helps, adjList is a
Map<V,ArrayList<V>> adjList;
And i'm just trying to start off with a directed unweighted Graph to make things easier
java
asked Nov 21 at 3:44
Jesus Epps
13
New contributor
Jesus Epps is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
|
show 1 more comment
up vote
0
down vote
favorite
I'm trying to learn different Data Structures and I'm currently struggling on Graphs.
I am trying to implement an Adjacency List using a Map of Linked Lists. This lets me be able to search up the name of the vertex and see all its connections quickly.
But I am having trouble actually adding any connections. What I'm currently doing is
public void add(V vertexName) {
if (!contains(vertexName)) {
ArrayList<V> array = new ArrayList<>();
adjList.put(vertexName,array);
}
}
public void connect(V start, V destination) {
if (!contains(start) || !contains(destination))
throw new NoSuchElementException();
adjList.get(start).add(destination); //adds destination to starts arraylist
}
System.out.print(adjList.toString);
But, for example, if I add 12, 10, and 20 to my list and then connect 20 and 12, I still just get:
12
10
20
instead of
12
10
20 - > 12
Any tips would be much appreciated. If it helps, adjList is a
Map<V,ArrayList<V>> adjList;
And i'm just trying to start off with a directed unweighted Graph to make things easier
java
asked Nov 21 at 3:44
Jesus Epps
13
New contributor
Jesus Epps is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Are you sure it's not to do with how you're displaying it?
– immibis
Nov 21 at 3:48
Shouldn't it print out correctly if I just simply print out each ArrayList using the toString method?
– Jesus Epps
Nov 21 at 3:52
Better show your complete code, including initialisation and printing.
– Ricky Mo
Nov 21 at 3:55
Can you show the code which prints unexpected result?
– talex
Nov 21 at 4:04
I've added all relevant code.
– Jesus Epps
Nov 21 at 4:08
|
show 1 more comment
up vote
0
down vote
favorite
up vote
0
down vote
favorite
I'm trying to learn different Data Structures and I'm currently struggling on Graphs.
I am trying to implement an Adjacency List using a Map of Linked Lists. This lets me be able to search up the name of the vertex and see all its connections quickly.
But I am having trouble actually adding any connections. What I'm currently doing is
public void add(V vertexName) {
if (!contains(vertexName)) {
ArrayList<V> array = new ArrayList<>();
adjList.put(vertexName,array);
}
}
public void connect(V start, V destination) {
if (!contains(start) || !contains(destination))
throw new NoSuchElementException();
adjList.get(start).add(destination); //adds destination to starts arraylist
}
System.out.print(adjList.toString);
But, for example, if I add 12, 10, and 20 to my list and then connect 20 and 12, I still just get:
12
10
20
instead of
12
10
20 - > 12
Any tips would be much appreciated. If it helps, adjList is a
Map<V,ArrayList<V>> adjList;
And i'm just trying to start off with a directed unweighted Graph to make things easier
java
asked Nov 21 at 3:44
Jesus Epps
13
New contributor
Jesus Epps is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
I'm trying to learn different Data Structures and I'm currently struggling on Graphs.
I am trying to implement an Adjacency List using a Map of Linked Lists. This lets me be able to search up the name of the vertex and see all its connections quickly.
But I am having trouble actually adding any connections. What I'm currently doing is
public void add(V vertexName) {
if (!contains(vertexName)) {
ArrayList<V> array = new ArrayList<>();
adjList.put(vertexName,array);
}
}
public void connect(V start, V destination) {
if (!contains(start) || !contains(destination))
throw new NoSuchElementException();
adjList.get(start).add(destination); //adds destination to starts arraylist
}
System.out.print(adjList.toString);
But, for example, if I add 12, 10, and 20 to my list and then connect 20 and 12, I still just get:
12
10
20
instead of
12
10
20 - > 12
Any tips would be much appreciated. If it helps, adjList is a
Map<V,ArrayList<V>> adjList;
And i'm just trying to start off with a directed unweighted Graph to make things easier
java
java
asked Nov 21 at 3:44
Jesus Epps
13
New contributor
Jesus Epps is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked Nov 21 at 3:44
Jesus Epps
13
New contributor
Jesus Epps is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited Nov 21 at 4:08
asked Nov 21 at 3:44
Jesus Epps
13
New contributor
Jesus Epps is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked Nov 21 at 3:44
Jesus Epps
13
asked Nov 21 at 3:44
Jesus Epps
13
13
New contributor
Jesus Epps is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Jesus Epps is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Jesus Epps is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Are you sure it's not to do with how you're displaying it?
– immibis
Nov 21 at 3:48
Shouldn't it print out correctly if I just simply print out each ArrayList using the toString method?
– Jesus Epps
Nov 21 at 3:52
Better show your complete code, including initialisation and printing.
– Ricky Mo
Nov 21 at 3:55
Can you show the code which prints unexpected result?
– talex
Nov 21 at 4:04
I've added all relevant code.
– Jesus Epps
Nov 21 at 4:08
|
show 1 more comment
Are you sure it's not to do with how you're displaying it?
– immibis
Nov 21 at 3:48
Shouldn't it print out correctly if I just simply print out each ArrayList using the toString method?
– Jesus Epps
Nov 21 at 3:52
Better show your complete code, including initialisation and printing.
– Ricky Mo
Nov 21 at 3:55
Can you show the code which prints unexpected result?
– talex
Nov 21 at 4:04
I've added all relevant code.
– Jesus Epps
Nov 21 at 4:08
Are you sure it's not to do with how you're displaying it?
– immibis
Nov 21 at 3:48
Are you sure it's not to do with how you're displaying it?
– immibis
Nov 21 at 3:48
Shouldn't it print out correctly if I just simply print out each ArrayList using the toString method?
– Jesus Epps
Nov 21 at 3:52
Shouldn't it print out correctly if I just simply print out each ArrayList using the toString method?
– Jesus Epps
Nov 21 at 3:52
Better show your complete code, including initialisation and printing.
– Ricky Mo
Nov 21 at 3:55
Better show your complete code, including initialisation and printing.
– Ricky Mo
Nov 21 at 3:55
Can you show the code which prints unexpected result?
– talex
Nov 21 at 4:04
Can you show the code which prints unexpected result?
– talex
Nov 21 at 4:04
I've added all relevant code.
– Jesus Epps
Nov 21 at 4:08
I've added all relevant code.
– Jesus Epps
Nov 21 at 4:08
|
show 1 more comment
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Jesus Epps is a new contributor. Be nice, and check out our Code of Conduct.
Jesus Epps is a new contributor. Be nice, and check out our Code of Conduct.
Jesus Epps is a new contributor. Be nice, and check out our Code of Conduct.
Jesus Epps is a new contributor. Be nice, and check out our Code of Conduct.
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Are you sure it's not to do with how you're displaying it?
– immibis
Nov 21 at 3:48
Shouldn't it print out correctly if I just simply print out each ArrayList using the toString method?
– Jesus Epps
Nov 21 at 3:52
Better show your complete code, including initialisation and printing.
– Ricky Mo
Nov 21 at 3:55
Can you show the code which prints unexpected result?
– talex
Nov 21 at 4:04
I've added all relevant code.
– Jesus Epps
Nov 21 at 4:08