object oriented – Modeling a Call Center in Java (Multi – Thread Approach)

I wanted to give a shot to Modeling a Call Center from Cracking the Coding Interview. The problem statement is as follows:

You have a call center with three levels of employees: Respondent, Manager, Director. An incoming phone call must be allocated to a respondent who is free. If they can not handle the call, they must escalate it to a manager. If the manager is not free to handle it, the call should be escalated to a director.

Here is my implementation in Java, which accepts calls from the command line in the form of: level,duration. For example entering: 0,25 represents a call that can be handled by a Respondant (level 0) and that will take 25 seconds to complete.

The code should be easy to just copy / paste to an IDE or just compile with javac in case you want to play with it in your local environment. Simply save it in CallCenter.java in global package and you are good to go.

import java.util.Arrays;
import java.util.List;
import java.util.Scanner;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;

import static java.lang.Integer.parseInt;

public class CallCenter {

    static BlockingQueue respondantQueue = new ArrayBlockingQueue<>(20);
    static BlockingQueue directorQueue = new ArrayBlockingQueue<>(20);

    static List managers = Arrays.asList(new Manager("Manager - 1"), new Manager("Manager - 2"));

    public static void main(String() args) throws Exception {
        new CallCenter().operate();
    }

    void operate() throws InterruptedException {
        Arrays.asList(new Respondant("Respondant - 1"), new Respondant("Respondant - 2"));
        Arrays.asList(new Director("The Director"));

        System.out.println("Enter values representing call in the format: 0,25.");
        System.out.println("First value is level required, second value is call duration.");
        Scanner scanner = new Scanner(System.in);
        while (true) {
            String s = scanner.nextLine();
            if ("q".equals(s)) {
                break;
            }
            String() split = s.split(",");
            Call call = new Call(parseInt(split(0)), parseInt(split(1)));
            dispatchCall(call);
        }
        scanner.close();
        System.exit(0);
    }

    private void dispatchCall(Call call) throws InterruptedException {
        respondantQueue.put(call);
    }
}

class Call {

    static int idCounter = 0;

    int id;
    int durationInSeconds;
    int level;

    public Call(int level, int durationInSeconds) {
        this.level = level;
        this.durationInSeconds = durationInSeconds;
        this.id = idCounter++;
    }

    @Override
    public String toString() {
        return "Call{" + "id=" + id + ", duration(sec)=" + durationInSeconds + ", level=" + level + '}';
    }
}

class Respondant {
    String name;

    public Respondant(String name) {
        this.name = name;
        new Thread(() -> {
            while (true) {
                try {
                    Call call = CallCenter.respondantQueue.take();
                    if (call.level == 0) {
                        System.out.println(name + " handling call: " + call);
                        Thread.sleep(call.durationInSeconds * 1000);
                    } else {
                        boolean managerHandled = false;
                        for (Manager manager : CallCenter.managers) {
                            if (!manager.isBusy) {
                                manager.acceptCall(call);
                                managerHandled = true;
                                break;
                            }
                        }
                        if (!managerHandled) {
                            CallCenter.directorQueue.put(call);
                        }
                    }
                } catch (InterruptedException ignored) {}
            }
        }).start();
    }
}

class Manager {
    String name;
    volatile boolean isBusy = false;

    public Manager(String name) {
        this.name = name;
    }

    void acceptCall(Call call) {
        new Thread(() -> {
            try {
                isBusy = true;
                if (call.level == 1) {
                    System.out.println(name + " handling call: " + call);
                    Thread.sleep(call.durationInSeconds * 1000);
                } else {
                    CallCenter.directorQueue.put(call);
                }
                isBusy = false;
            } catch (InterruptedException ignored) {}
        }).start();
    }
}

class Director {
    String name;

    public Director(String name) {
        this.name = name;
        new Thread(() -> {
            while (true) {
                try {
                    Call call = CallCenter.directorQueue.take();
                    System.out.println(name + " handling call: " + call);
                    Thread.sleep(call.durationInSeconds * 1000 / 4); // Director handles calls 4 times faster!
                } catch (InterruptedException ignored) {}
            }
        }).start();
    }
}

A sample run for me is as follows:

Enter values representing call in the format: 0,25.
First value is level required, second value is call duration.
0,5
Respondant - 1 handling call: Call{id=0, duration(sec)=5, level=0}
0,5
Respondant - 2 handling call: Call{id=1, duration(sec)=5, level=0}
1,5
Manager - 1 handling call: Call{id=2, duration(sec)=5, level=1}
1,5
Manager - 2 handling call: Call{id=3, duration(sec)=5, level=1}
1,5
The Director handling call: Call{id=4, duration(sec)=5, level=1}

Any feedback is welcome.

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gr.group theory – Groups with exponentially growing center

Given a finite group $ G $ and a finite subset $ S $, let $ omega_G (S) = inf_ {n geq1} | S ^ n | ^ {1 / n} $ (this is the exponential growth rate of $ S $).

  1. Is there a finite group $ G $ with the center $ Z $ and symmetrical generator $ S $ such as $ omega_ {G / Z} (SZ / Z) < omega_G (S) $?

Here is my idea for a construction. Let $ H $ be the discreet group of Heisenberg, and let $ varphi $ to be an automorphism of $ H $ which acts on $ H ^ text {ab} cong mathbf {Z} ^ 2 $ as a matrix of eigenvalue $ lambda> $ 1and let $ G = H rtimes_ varphi mathbf {Z} $. Let $ S $ be the union of standard gensets for $ H $ and $ mathbf {Z} $. Note that $ varphi $ keeps the center of $ H $, so $ Z (G) = Z (H) cong mathbf {Z} $, and $ G / Z (G) cong mathbf {Z} ^ 2 r r n varphi mathbf {Z} $. Since $ lambda> $ 1 we have exponential growth $ G / Z (G) $, and my intuition is that there is enough extra space in $ H $ that we should have even greater growth in $ G $. The details I miss though, and maybe someone has a reference or a simpler example.

Assuming the answer to question 1 is "yes", it follows that $ | S ^ n cap Z | $ grows exponentially. Indeed since $ S ^ n $ grow much faster than $ S ^ n Z / Z $, the maximum size of the fiber $ max_g | S ^ n cap gZ | $ must grow exponentially, and $ | S ^ n cap gZ | leq | S ^ {2n} cap Z | $.

  1. How fast can $ | S ^ n cap Z | $ grow in relation to $ | S ^ n | $? In other words, what is the supremum of $ inf_ {n geq1} | S ^ n cap Z | ^ {1 / n} / omega_G (S) $ mostly $ G $ and $ S $? Is $ 1 $?

For the moment, I can not even convince myself that you could not even have $ | S ^ n cap Z | gg | S ^ n | $ for everyone $ n $.

Finally, a technical question.

  1. Do we always $ | S ^ n cap Z | ^ {1 / n} to omega_G (S) / omega_ {GZ / Z} (SZ / Z) $?

According to the argument made before the second stage, the exponential growth rate of $ | S ^ n cap Z | $ Is at least $ ( omega_G (S) / omega_ {G / Z} (SZ / Z)) ^ {1/2} $. It's plausible but not obvious that the biggest fiber on $ Z $ is $ S ^ n cap Z $ itself, so it is plausible that we can remove the square root. The other inequality is more suspect because we could have a lot of small fibers.

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alignment – Should the columns of the read-only Boolean grid be aligned in the center?

I find no reason to align "Yes / No" on the right or center simply because they are Booleans.

The numbers are aligned to the right to help the reader compare the scale more easily when scanning columns.

If this column is important, you can use tags for yes / no to highlight the information, with a different background and focus on the text.

enter the description of the image here

Is it possible to have a same day appointment without appointment at the Global Entry Registration Center in Taipei (Taipei, Da? District)?

Is it possible to have an appointment without an appointment the same day at the Taipei Global Entry Registration Center (Taipei, Da? Year district)?

I could not find any information on the official Global Entry website (https://ttp.cbp.dhs.gov/schedulerui/):

e

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You want to buy US telephone wires for the call center

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physics – how to calculate the resulting velocity and the angular velocity that the rocket has on the center of mass

The problem I encounter is that I do not understand how to apply the force of a rocket to a center of mass.

for example.
Let's call the body & # 39; ship & # 39;

the "vessel" is equal to 1000 (relative unit) and the center of mass is normalized to (0.0) (origin)

the "ship" has two rockets (say for the thrust vector), one at (-2, -4) (left) and one at (2, -4) (right) with respect to the center of mass, and both had downward pointing nozzles (90-degree angle counterclockwise from x)

if the left rocket were to fire at 500 (relative units), what formula could I use to find the resulting force and angular force on the center of mass?

if it helps, the language is a superset of javascript (a custom preparer similar to the handwritten text), and I use a custom physics engine that only accepts force on the center of gravity as a table, for example. (force x, force y, angular force). I tried to recycle my collision detection algorithm, but it was like driving a square into a circle-shaped hole.

I've been looking for it since last night and I can not seem to find a formula to do it (at least not one that I can understand, I do not understand complex mathematical notations).

Any help is greatly appreciated.

TL; DR
I need a formula that gives the resultant force and the angular force of a rocket shifted to the center of gravity where the result is as follows:

(force x, force y, angular force)

the center of mass is standardized at the origin,

and take the variables:
rocket shift ((x, y)),
angle of the rocket (in degrees from the center of the mass),
rocket strength (in relative units)