₦airaland Forum

realnaija:
Funny, I am actually doing that as we speak.

Seun:
Makes no sense.  You're saying many contradictory things in your desperate bid to disagree.  Na wa.
What is your reason (why there are very few old web devs?)

Seun:
The reason we don't have 70 year old web developers is simple: the web is barely 20 years old!

candylips:
Nice one logica. alpha-beta pruning looks like a very solid search algorithm

Seun:
Excellent topic. I've not fully figured out this algorithm yet, but it's really useful.

package com.blackplanet.puzzle;

import java.io.BufferedReader;
import java.io.FileReader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Stack;
import java.util.StringTokenizer;

public class ShortestUserPath implements Runnable {
	private String connectionsFileName;
	
	private String startUserName;
	
	private String endUserName;

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		shortest finder = new shortest();
		//Making sure all the required parameters are entered proper.
		if(args.length < 3) {
			System.out.println("Come on dude, you did it wrong!\nUsage:\njava com.blackplanet.puzzle.shortest <relations-file-name> <start-user-name> <end-user-name>";
		} if(args.length > 3) {
			System.out.println("Come on dude, you did it wrong!Usage:\njava com.blackplanet.puzzle.shortest <relations-file-name> <start-user-name> <end-user-name>";
		} 
		else {
			finder.setConnectionsFileName(args[0]);
			finder.setStartUserName(args[1]);
			finder.setEndUserName(args[2]);
			Thread finderThread = new Thread(finder);
			
			finderThread.start();

		}		
	}

	public void run() {
		List<BPMember> members = loadMembers(connectionsFileName);
		
//Tree (binary-tree in the case of sample data, technically speaking) representation of BlackPlanet sample members		
//		System.out.println("Member List: " + members);
		
		String shortestPath = exec(startUserName, endUserName, members);
		
		System.out.println(shortestPath);
	}
	
	public List<BPMember> loadMembers(String fileName) {
		List<BPMember> members = new ArrayList<BPMember>();
		
		BufferedReader reader;
		try {
			reader = new BufferedReader(new FileReader(fileName));
			String line = null;
			String memberName = null;
			String connectedMemberName = null;
			while((line = reader.readLine()) != null) {
				StringTokenizer tk = new StringTokenizer(line, " ";
				memberName = tk.nextToken();
				connectedMemberName = tk.nextToken();
				
				BPMember member = new BPMember(memberName);
				if(!members.contains(member)) {
					members.add(member);
				} else {
					member = members.get(members.indexOf(member));
				}
				
				BPMember connectedMember = new BPMember(connectedMemberName);
				if(!members.contains(connectedMember)) {
					members.add(connectedMember);
				} else {
					connectedMember = members.get(members.indexOf(connectedMember));
				}
				
				if(!connectedMember.getConnectingNodes().contains(member)) {
					connectedMember.addConnectingNode(member);
				}
				if(!member.getConnectingNodes().contains(connectedMember)) {
					member.addConnectingNode(connectedMember);
				}
			}			
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}			
		
		return members;
	}
	
	public String exec(String startUserName, String endUserName, List<BPMember> members) {
		StringBuilder builder = new StringBuilder();
		
		int memberIdx = members.indexOf(new BPMember(startUserName));
		BPMember startUser = null;
		if(memberIdx >= 0) {
			startUser = members.get(memberIdx);			
		}
			
		memberIdx = members.indexOf(new BPMember(endUserName));
		BPMember endUser = null;
		if(memberIdx >= 0) {
			endUser = members.get(memberIdx);			
		}

		if(startUser != null && endUser != null) {
//			System.out.println("Ready or not, here I come, you can't hide, ";
			Stack<String> currentPath = new Stack<String>();
			ArrayList<Stack<String>> pathSolutions = new ArrayList<Stack<String>>();
//			long startTime = System.currentTimeMillis();
			startUser.findConnection(new BPMember(startUserName), new BPMember(startUserName), new BPMember(endUserName), members.size(), members.size(), currentPath, pathSolutions);
//			long timeInterval = System.currentTimeMillis() - startTime;
			
			if(!pathSolutions.isEmpty()) {
//				System.out.println(", I think I found something, better check.";
//				System.out.println(pathSolutions);
				
//				Figuring out the path with the shortest length, 				
				ArrayList<Long> pathLengths = new ArrayList<Long>();
				for(Iterator<Stack<String>> itr = pathSolutions.iterator(); itr.hasNext(); ) {
					pathLengths.add(new Long(itr.next().size()));
				}
				Collections.sort(pathLengths);
				long optimalPathLength = pathLengths.get(0);

//				System.out.println("OPTIMAL_PATH_LENGTH: " + optimalPathLength);
				
				ArrayList<Stack<String>> optimalPaths = new ArrayList<Stack<String>>();
				optimalPaths.addAll(pathSolutions);				
				
				Stack<String> path = null;
				for(Iterator<Stack<String>> itr = pathSolutions.iterator(); itr.hasNext(); ) {
					path = itr.next();
					if(path.size() > optimalPathLength) {
						optimalPaths.remove(path);
//Separating the chaff from the wheat.
//						System.out.println("Removing the garbage " + path + ", ";
//						System.out.println("OPTIMAL_PATH_REDUCED: " + optimalPaths);
					}
				}
				
				ArrayList<String> optimalPathStrings = new ArrayList<String>();
				
//				System.out.println("And here we are folks!: " + optimalPaths);
				
				Stack<String> aPath = null;
				
				for(Iterator<Stack<String>> itr = optimalPaths.iterator(); itr.hasNext(); ) {
					aPath = itr.next();
					StringBuilder bldr = new StringBuilder();
					for(Iterator<String> j = aPath.iterator(); j.hasNext(); ) {
						bldr.append(j.next());
						if(j.hasNext()) {
							bldr.append(" ";
						}						
					}
					optimalPathStrings.add(bldr.toString());
				}
				Collections.sort(optimalPathStrings);
				
				for(Iterator<String> itr = optimalPathStrings.iterator(); itr.hasNext(); ) {
					builder.append(itr.next());
					if(itr.hasNext()) {
						builder.append("\n";
					}
				}
			} else {
//				System.out.println("Awwww man! What a waste of time. I want my " + ((double) timeInterval) / 1000.0  + " secs back";
				builder.append("NONE";
			}
		} else if(startUser == null){
			builder.append("Come on dude, we don't have anybody called '" + startUserName + "' in here!";
		} else if(endUser == null){
			builder.append("Come on dude, we don't have anybody called " + endUserName + "' in here!";
		}
		
		return builder.toString();
	}

	public void setConnectionsFileName(String connectionsFile) {
		this.connectionsFileName = connectionsFile;
	}

	public String getConnectionsFileName() {
		return connectionsFileName;
	}

	public void setStartUserName(String startUserName) {
		this.startUserName = startUserName;
	}

	public String getStartUserName() {
		return startUserName;
	}

	public void setEndUserName(String endUserName) {
		this.endUserName = endUserName;
	}

	public String getEndUserName() {
		return endUserName;
	}
}

function alphabeta(node, depth, α, β)         
    (* β represents previous player best choice - doesn't want it if α would worsen it *)
    if  depth = 0 "or" node is a terminal node
        return the heuristic value of node
    foreach child of node
        α := max(α, -alphabeta(child, depth-1, -β, -α))     
        (* use symmetry, -β becomes subsequently pruned α *)
        if β≤α
            break                             (* Beta cut-off *)
    return α

(* Initial call *)
alphabeta(origin, depth, -infinity, +infinity)

package com.blackplanet.puzzle;

import java.io.BufferedReader;
import java.io.FileReader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Stack;
import java.util.StringTokenizer;

public class shortest implements Runnable {
	private String connectionsFileName;
	
	private String startUserName;
	
	private String endUserName;

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		shortest finder = new shortest();
		//Making sure all the required parameters are entered proper.
		if(args.length < 3) {
			System.out.println("Come on dude, you did it wrong!\nUsage:\njava com.blackplanet.puzzle.shortest <relations-file-name> <start-user-name> <end-user-name>";
		} if(args.length > 3) {
			System.out.println("Come on dude, you did it wrong!Usage:\njava com.blackplanet.puzzle.shortest <relations-file-name> <start-user-name> <end-user-name>";
		} 
		else {
			finder.setConnectionsFileName(args[0]);
			finder.setStartUserName(args[1]);
			finder.setEndUserName(args[2]);
			Thread finderThread = new Thread(finder);
			
			finderThread.start();

		}		
	}

	public void run() {
		List<BPMember> members = loadMembers(connectionsFileName);
		
//Tree (binary-tree in the case of sample data, technically speaking) representation of BlackPlanet sample members		
//		System.out.println("Member List: " + members);
		
		String shortestPath = exec(startUserName, endUserName, members);
		
		System.out.println(shortestPath);
	}
	
	public List<BPMember> loadMembers(String fileName) {
		List<BPMember> members = new ArrayList<BPMember>();
		
		BufferedReader reader;
		try {
			reader = new BufferedReader(new FileReader(fileName));
			String line = null;
			String memberName = null;
			String connectedMemberName = null;
			while((line = reader.readLine()) != null) {
				StringTokenizer tk = new StringTokenizer(line, " ";
				memberName = tk.nextToken();
				connectedMemberName = tk.nextToken();
				
				BPMember member = new BPMember(memberName);
				if(!members.contains(member)) {
					members.add(member);
				} else {
					member = members.get(members.indexOf(member));
				}
				
				BPMember connectedMember = new BPMember(connectedMemberName);
				if(!members.contains(connectedMember)) {
					members.add(connectedMember);
				} else {
					connectedMember = members.get(members.indexOf(connectedMember));
				}
				
				if(!connectedMember.getConnectingNodes().contains(member)) {
					connectedMember.addConnectingNode(member);
				}
				if(!member.getConnectingNodes().contains(connectedMember)) {
					member.addConnectingNode(connectedMember);
				}
			}			
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}			
		
		return members;
	}
	
	public String exec(String startUserName, String endUserName, List<BPMember> members) {
		StringBuilder builder = new StringBuilder();
		
		int memberIdx = members.indexOf(new BPMember(startUserName));
		BPMember startUser = null;
		if(memberIdx >= 0) {
			startUser = members.get(memberIdx);			
		}
			
		memberIdx = members.indexOf(new BPMember(endUserName));
		BPMember endUser = null;
		if(memberIdx >= 0) {
			endUser = members.get(memberIdx);			
		}

		if(startUser != null && endUser != null) {
//			System.out.println("Ready or not, here I come, you can't hide, ";
			Stack<String> currentPath = new Stack<String>();
			ArrayList<Stack<String>> pathSolutions = new ArrayList<Stack<String>>();
//			long startTime = System.currentTimeMillis();
			startUser.findConnection(new BPMember(startUserName), new BPMember(startUserName), new BPMember(endUserName), members.size(), members.size(), currentPath, pathSolutions);
//			long timeInterval = System.currentTimeMillis() - startTime;
			
			if(!pathSolutions.isEmpty()) {
//				System.out.println(", I think I found something, better check.";
//				System.out.println(pathSolutions);
				
//				Figuring out the path with the shortest length, 				
				ArrayList<Long> pathLengths = new ArrayList<Long>();
				for(Iterator<Stack<String>> itr = pathSolutions.iterator(); itr.hasNext(); ) {
					pathLengths.add(new Long(itr.next().size()));
				}
				Collections.sort(pathLengths);
				long optimalPathLength = pathLengths.get(0);

//				System.out.println("OPTIMAL_PATH_LENGTH: " + optimalPathLength);
				
				ArrayList<Stack<String>> optimalPaths = new ArrayList<Stack<String>>();
				optimalPaths.addAll(pathSolutions);				
				
				Stack<String> path = null;
				for(Iterator<Stack<String>> itr = pathSolutions.iterator(); itr.hasNext(); ) {
					path = itr.next();
					if(path.size() > optimalPathLength) {
						optimalPaths.remove(path);
//Separating the chaff from the wheat.
//						System.out.println("Removing the garbage " + path + ", ";
//						System.out.println("OPTIMAL_PATH_REDUCED: " + optimalPaths);
					}
				}
				
				ArrayList<String> optimalPathStrings = new ArrayList<String>();
				
//				System.out.println("And here we are folks!: " + optimalPaths);
				
				Stack<String> aPath = null;
				
				for(Iterator<Stack<String>> itr = optimalPaths.iterator(); itr.hasNext(); ) {
					aPath = itr.next();
					StringBuilder bldr = new StringBuilder();
					for(Iterator<String> j = aPath.iterator(); j.hasNext(); ) {
						bldr.append(j.next());
						if(j.hasNext()) {
							bldr.append(" ";
						}						
					}
					optimalPathStrings.add(bldr.toString());
				}
				Collections.sort(optimalPathStrings);
				
				for(Iterator<String> itr = optimalPathStrings.iterator(); itr.hasNext(); ) {
					builder.append(itr.next());
					if(itr.hasNext()) {
						builder.append("\n";
					}
				}
			} else {
//				System.out.println("Awwww man! What a waste of time. I want my " + ((double) timeInterval) / 1000.0  + " secs back";
				builder.append("NONE";
			}
		} else if(startUser == null){
			builder.append("Come on dude, we don't have anybody called '" + startUserName + "' in here!";
		} else if(endUser == null){
			builder.append("Come on dude, we don't have anybody called " + endUserName + "' in here!";
		}
		
		return builder.toString();
	}

	public void setConnectionsFileName(String connectionsFile) {
		this.connectionsFileName = connectionsFile;
	}

	public String getConnectionsFileName() {
		return connectionsFileName;
	}

	public void setStartUserName(String startUserName) {
		this.startUserName = startUserName;
	}

	public String getStartUserName() {
		return startUserName;
	}

	public void setEndUserName(String endUserName) {
		this.endUserName = endUserName;
	}

	public String getEndUserName() {
		return endUserName;
	}
}

candylips:
you are right most of the regular developer roles don't even ask for degree or certificate

candylips:
where  ?? nigeria ?? thats not the case for this place o. experience is the king here and probably an advance degree in CS

candylips:
yea SCJEA makes more sense. Am done with IT certifications though. they are just not worth it.

candylips:
SCJP is a useless certification

The certificate has been collecting dust on my bookshelf since 2003

candylips:
do you need a bricklayer that can build these applications

IG:
Interesting statistics. So are you now implying that the more popular the language the better features it has?