How to connect 2 vertexes in an Adjacency List?
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 '18 at 3:44
Jesus Epps
34
|
show 1 more comment
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 '18 at 3:44
Jesus Epps
34
Are you sure it's not to do with how you're displaying it?
– immibis
Nov 21 '18 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 '18 at 3:52
Better show your complete code, including initialisation and printing.
– Ricky Mo
Nov 21 '18 at 3:55
Can you show the code which prints unexpected result?
– talex
Nov 21 '18 at 4:04
I've added all relevant code.
– Jesus Epps
Nov 21 '18 at 4:08
|
show 1 more comment
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 '18 at 3:44
Jesus Epps
34
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 '18 at 3:44
Jesus Epps
34
asked Nov 21 '18 at 3:44
Jesus Epps
34
edited Nov 21 '18 at 4:08
asked Nov 21 '18 at 3:44
Jesus Epps
34
asked Nov 21 '18 at 3:44
Jesus Epps
34
asked Nov 21 '18 at 3:44
Jesus Epps
34
34
Are you sure it's not to do with how you're displaying it?
– immibis
Nov 21 '18 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 '18 at 3:52
Better show your complete code, including initialisation and printing.
– Ricky Mo
Nov 21 '18 at 3:55
Can you show the code which prints unexpected result?
– talex
Nov 21 '18 at 4:04
I've added all relevant code.
– Jesus Epps
Nov 21 '18 at 4:08
|
show 1 more comment
Are you sure it's not to do with how you're displaying it?
– immibis
Nov 21 '18 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 '18 at 3:52
Better show your complete code, including initialisation and printing.
– Ricky Mo
Nov 21 '18 at 3:55
Can you show the code which prints unexpected result?
– talex
Nov 21 '18 at 4:04
I've added all relevant code.
– Jesus Epps
Nov 21 '18 at 4:08
Are you sure it's not to do with how you're displaying it?
– immibis
Nov 21 '18 at 3:48
Are you sure it's not to do with how you're displaying it?
– immibis
Nov 21 '18 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 '18 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 '18 at 3:52
Better show your complete code, including initialisation and printing.
– Ricky Mo
Nov 21 '18 at 3:55
Better show your complete code, including initialisation and printing.
– Ricky Mo
Nov 21 '18 at 3:55
Can you show the code which prints unexpected result?
– talex
Nov 21 '18 at 4:04
Can you show the code which prints unexpected result?
– talex
Nov 21 '18 at 4:04
I've added all relevant code.
– Jesus Epps
Nov 21 '18 at 4:08
I've added all relevant code.
– Jesus Epps
Nov 21 '18 at 4:08
|
show 1 more comment
0
active
oldest
votes
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53404966%2fhow-to-connect-2-vertexes-in-an-adjacency-list%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
0
active
oldest
votes
0
active
oldest
votes
active
oldest
votes
active
oldest
votes
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Some of your past answers have not been well-received, and you're in danger of being blocked from answering.
Please pay close attention to the following guidance:
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53404966%2fhow-to-connect-2-vertexes-in-an-adjacency-list%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Are you sure it's not to do with how you're displaying it?
– immibis
Nov 21 '18 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 '18 at 3:52
Better show your complete code, including initialisation and printing.
– Ricky Mo
Nov 21 '18 at 3:55
Can you show the code which prints unexpected result?
– talex
Nov 21 '18 at 4:04
I've added all relevant code.
– Jesus Epps
Nov 21 '18 at 4:08