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import java.util.ArrayList; | |
import java.util.LinkedList; | |
import java.util.Queue; | |
import java.util.Stack; | |
public class Graph | |
{ | |
public Node rootNode; | |
public ArrayList nodes=new ArrayList(); | |
public int[][] adjMatrix;//Edges will be represented as adjacency Matrix | |
int size; | |
public void setRootNode(Node n) | |
{ | |
this.rootNode=n; | |
} | |
public Node getRootNode() | |
{ | |
return this.rootNode; | |
} | |
public void addNode(Node n) | |
{ | |
nodes.add(n); | |
} | |
//This method will be called to make connect two nodes | |
public void connectNode(Node start,Node end) | |
{ | |
if(adjMatrix==null) | |
{ | |
size=nodes.size(); | |
adjMatrix=new int[size][size]; | |
} | |
int startIndex=nodes.indexOf(start); | |
int endIndex=nodes.indexOf(end); | |
adjMatrix[startIndex][endIndex]=1; | |
adjMatrix[endIndex][startIndex]=1; | |
} | |
private Node getUnvisitedChildNode(Node n) | |
{ | |
int index=nodes.indexOf(n); | |
int j=0; | |
while(j<size) | |
{ | |
if(adjMatrix[index][j]==1 && ((Node)nodes.get(j)).visited==false) | |
{ | |
return (Node)nodes.get(j); | |
} | |
j++; | |
} | |
return null; | |
} | |
//BFS traversal of a tree is performed by the bfs() function | |
public void bfs() | |
{ | |
//BFS uses Queue data structure | |
Queue q=new LinkedList(); | |
q.add(this.rootNode); | |
printNode(this.rootNode); | |
rootNode.visited=true; | |
while(!q.isEmpty()) | |
{ | |
Node n=(Node)q.remove(); | |
Node child=null; | |
while((child=getUnvisitedChildNode(n))!=null) | |
{ | |
child.visited=true; | |
printNode(child); | |
q.add(child); | |
} | |
} | |
//Clear visited property of nodes | |
clearNodes(); | |
} | |
public Node bfs_find(char search_label) | |
{ | |
//BFS uses Queue data structure | |
Queue q=new LinkedList(); | |
q.add(this.rootNode); | |
if(this.rootNode.label == search_label) { | |
return this.rootNode; | |
} | |
rootNode.visited=true; | |
while(!q.isEmpty()) | |
{ | |
Node n=(Node)q.remove(); | |
Node child=null; | |
while((child=getUnvisitedChildNode(n))!=null) | |
{ | |
child.visited=true; | |
if(child.label == search_label){ | |
return child; | |
} | |
q.add(child); | |
} | |
} | |
//Clear visited property of nodes | |
clearNodes(); | |
return null; | |
} | |
//DFS traversal of a tree is performed by the dfs() function | |
public void dfs() | |
{ | |
//DFS uses Stack data structure | |
Stack s=new Stack(); | |
s.push(this.rootNode); | |
rootNode.visited=true; | |
printNode(rootNode); | |
while(!s.isEmpty()) | |
{ | |
Node n=(Node)s.peek(); | |
Node child=getUnvisitedChildNode(n); | |
if(child!=null) | |
{ | |
child.visited=true; | |
printNode(child); | |
s.push(child); | |
} | |
else | |
{ | |
s.pop(); | |
} | |
} | |
//Clear visited property of nodes | |
clearNodes(); | |
} | |
//Utility methods for clearing visited property of node | |
private void clearNodes() | |
{ | |
int i=0; | |
while(i<size) | |
{ | |
Node n=(Node)nodes.get(i); | |
n.visited=false; | |
i++; | |
} | |
} | |
//Utility methods for printing the node's label | |
private void printNode(Node n) | |
{ | |
System.out.print(n.label+" "); | |
} | |
} |
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public class Main { | |
/** | |
* @param args | |
*/ | |
public static void main(String[] args) | |
{ | |
//Lets create nodes as given as an example in the article | |
Node nA=new Node('A'); | |
Node nB=new Node('B'); | |
Node nC=new Node('C'); | |
Node nD=new Node('D'); | |
Node nE=new Node('E'); | |
Node nF=new Node('F'); | |
//Create the graph, add nodes, create edges between nodes | |
Graph g=new Graph(); | |
g.addNode(nA); | |
g.addNode(nB); | |
g.addNode(nC); | |
g.addNode(nD); | |
g.addNode(nE); | |
g.addNode(nF); | |
g.setRootNode(nA); | |
g.connectNode(nA,nB); | |
g.connectNode(nA,nC); | |
g.connectNode(nA,nD); | |
g.connectNode(nB,nE); | |
g.connectNode(nB,nF); | |
g.connectNode(nC,nF); | |
//Perform the traversal of the graph | |
System.out.println("DFS Traversal of a tree is ------------->"); | |
g.dfs(); | |
Node found_node = g.bfs_find('C'); | |
System.out.println("Found Node- " + found_node.label); | |
System.out.println("\nBFS Traversal of a tree is ------------->"); | |
g.bfs(); | |
} | |
} |
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public class Node | |
{ | |
public char label; | |
public boolean visited=false; | |
public Node(char l) | |
{ | |
this.label=l; | |
} | |
} |
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