http://en.wikipedia.org/wiki/Breadth-first_search
http://en.wikipedia.org/wiki/Depth-first_search
Tree traversal in various languages
http://rosettacode.org/wiki/Tree_traversal#Java
Algorithms
http://algs4.cs.princeton.edu/home/
Graphs
http://algs4.cs.princeton.edu/40graphs/
Directed Graphs
http://algs4.cs.princeton.edu/42directed/
Java Data Structure: A Generic Tree
http://sujitpal.blogspot.com/2006/05/java-data-structure-generic-tree.html
Generic Node
public class Node<T> {
public T data;
public List<Node<T>> children;
public List<Node<T>> parents;
Non-generic node
package dave;
/**
* Non-generic subclass of Node<String>
*/
public class DaveNode extends Node<String> {
public DaveNode() {
super();
}
}
Walk using stack
/**
*
* @param element
* @return set of all nodes
*/
public List<Node<T>> walk(Node<T> element){
List<Node<T>> out = new ArrayList<Node<T>>();
Queue<Node<T>> q = new LinkedList<Node<T>>();
q.add(element);
while(!q.isEmpty()){
Node<T> x = q.poll();
out.add(x);
for(Node<T> child : x.getChildren()){
q.add(child);
}
}
return out;
}
Walk from bottom up
/**
*
* @param element
* @return set of all upper nodes
*/
public Collection<Node<T>> pathBottomUp(Node<T> element){
Set<Node<T>> out = new LinkedHashSet<Node<T>>();
Queue<Node<T>> q = new LinkedList<Node<T>>();
q.add(element);
while(!q.isEmpty()){
Node<T> x = q.poll();
out.add(x);
for(Node<T> parent : x.getParents()){
q.add(parent);
}
}
return out;
}
Construct tree
package dave;
public class WalkTree {
public static void main(String[] args) {
DaveTree daveTree = new DaveTree();
DaveNode daveNode = getDaveNode("1");
DaveNode daveNode11 = getDaveNode("1.1");
DaveNode daveNode12 = getDaveNode("1.2");
DaveNode daveNode13 = getDaveNode("1.3");
DaveNode daveNode131 = getDaveNode("1.3.1");
DaveNode daveNode132 = getDaveNode("1.3.2");
daveNode.addChild(daveNode11);
daveNode.addChild(daveNode12);
daveNode.addChild(daveNode13);
daveNode12.addChild(daveNode131);
daveNode13.addChild(daveNode131);
daveNode13.addChild(daveNode132);
daveTree.setRootElement(daveNode);
System.out.println(daveTree.toList());
Node<String> root = daveTree.getRootElement();
System.out.println("walk:" + daveTree.walk(root));
System.out.println("pathBottomUp:" +daveTree.pathBottomUp(daveNode131));
}
private static DaveNode getDaveNode(String profileName){
DaveNode daveNode = new DaveNode();
daveNode.setData(profileName);
return daveNode;
}
}
Program output
[{1,[1.1,1.2,1.3]}, {1.1,[]}, {1.2,[1.3.1]}, {1.3.1,[]}, {1.3,[1.3.1,1.3.2]}, {1.3.1,[]}, {1.3.2,[]}]
walk:[{1,[1.1,1.2,1.3]}, {1.1,[]}, {1.2,[1.3.1]}, {1.3,[1.3.1,1.3.2]}, {1.3.1,[]}, {1.3.1,[]}, {1.3.2,[]}]
pathBottomUp:[{1.3.1,[]}, {1.2,[1.3.1]}, {1.3,[1.3.1,1.3.2]}, {1,[1.1,1.2,1.3]}]
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