In the Zoho Round 3 coding challenge, one of the intriguing problems was to create a Call Taxi Booking Application. Here’s the exact question provided:
Question:
Design a call taxi booking application with the following constraints:
- There are 6 points (A, B, C, D, E, F) arranged linearly, and the distance between consecutive points is 15 km.
- The travel time between two consecutive points is 1 hour.
- All taxis start from point A.
- Minimum fare: Rs. 100 for the first 5 km. For every additional kilometer, Rs. 10 is charged.
- Allocate a free taxi that is closest to the customer. If two taxis are at the same distance, the one with lower earnings should be allotted.
- If no taxis are available, reject the booking.
- Display the earnings and booking details of each taxi after every booking.
This problem was an exciting mix of object-oriented programming and logical problem-solving. Here, I’ll walk you through the approach and solution.
Table of Contents
Solution Approach
The application was designed with three core components:
- Taxi Class: Represents the state and functionality of each taxi.
- Booking Class: Represents individual booking details.
- TaxiBookingSystem Class: Manages the taxis and processes bookings.
1. Taxi Class
The Taxi class encapsulates details about the current state of a taxi, including its location, total earnings, and booking history.
import java.util.*;
class Taxi {
int id;
char currentPoint = 'A';
int totalEarnings = 0;
List<Booking> bookings = new ArrayList<>();
public Taxi(int id) {
this.id = id;
}
public boolean isAvailable(int requestTime) {
if (bookings.isEmpty()) return true;
Booking lastBooking = bookings.get(bookings.size() - 1);
return lastBooking.dropTime <= requestTime;
}
public int calculateEarnings(char from, char to) {
int distance = Math.abs(to - from) * 15;
return 100 + Math.max(0, (distance - 5) * 10);
}
public void addBooking(Booking booking) {
bookings.add(booking);
totalEarnings += booking.amount;
currentPoint = booking.to;
}
}2. Booking Class
The Booking class stores the details of a single booking, including pickup and drop locations, fare, and timings.
class Booking {
int bookingId, customerId, pickupTime, dropTime, amount;
char from, to;
public Booking(int bookingId, int customerId, char from, char to, int pickupTime, int dropTime, int amount) {
this.bookingId = bookingId;
this.customerId = customerId;
this.from = from;
this.to = to;
this.pickupTime = pickupTime;
this.dropTime = dropTime;
this.amount = amount;
}
}3. TaxiBookingSystem Class
The TaxiBookingSystem class integrates everything, handling booking requests and displaying taxi details.
public class TaxiBookingSystem {
static List<Taxi> taxis = new ArrayList<>();
static Scanner sc = new Scanner(System.in);
static int customerCounter = 1;
public static void main(String[] args) {
System.out.print("Enter number of taxis: ");
int numTaxis = sc.nextInt();
initializeTaxis(numTaxis);
while (true) {
System.out.println("\n1. Book Taxi\n2. Display Taxi Details\n3. Exit");
System.out.print("Enter your choice: ");
int choice = sc.nextInt();
switch (choice) {
case 1:
bookTaxi();
break;
case 2:
displayTaxiDetails();
break;
case 3:
System.out.println("Exiting...");
return;
default:
System.out.println("Invalid choice. Try again.");
}
}
}
public static void initializeTaxis(int n) {
for (int i = 1; i <= n; i++) {
taxis.add(new Taxi(i));
}
}
public static void bookTaxi() {
int customerId = customerCounter++;
System.out.print("Enter Pickup Point (A-F): ");
char pickup = sc.next().toUpperCase().charAt(0);
System.out.print("Enter Drop Point (A-F): ");
char drop = sc.next().toUpperCase().charAt(0);
System.out.print("Enter Pickup Time (in hours): ");
int pickupTime = sc.nextInt();
Taxi selectedTaxi = null;
int minDistance = Integer.MAX_VALUE;
for (Taxi taxi : taxis) {
if (taxi.isAvailable(pickupTime)) {
int distance = Math.abs(taxi.currentPoint - pickup);
if (distance < minDistance ||
(distance == minDistance && taxi.totalEarnings < selectedTaxi.totalEarnings)) {
selectedTaxi = taxi;
minDistance = distance;
}
}
}
if (selectedTaxi == null) {
System.out.println("Booking rejected. No taxis available.");
return;
}
int dropTime = pickupTime + Math.abs(drop - pickup);
int amount = selectedTaxi.calculateEarnings(pickup, drop);
int bookingId = selectedTaxi.bookings.size() + 1;
Booking booking = new Booking(bookingId, customerId, pickup, drop, pickupTime, dropTime, amount);
selectedTaxi.addBooking(booking);
System.out.println("Taxi-" + selectedTaxi.id + " is allocated.");
}
public static void displayTaxiDetails() {
for (Taxi taxi : taxis) {
System.out.println("Taxi-" + taxi.id + " Total Earnings: Rs." + taxi.totalEarnings);
System.out.printf("%-10s %-10s %-5s %-5s %-12s %-9s %-6s%n",
"BookingID", "CustomerID", "From", "To", "PickupTime", "DropTime", "Amount");
for (Booking booking : taxi.bookings) {
System.out.printf("%-10d %-10d %-5c %-5c %-12d %-9d %-6d%n",
booking.bookingId, booking.customerId, booking.from, booking.to,
booking.pickupTime, booking.dropTime, booking.amount);
}
}
}
}Sample Input and Output
Input 1:
Customer ID: 1, Pickup: A, Drop: B, Pickup Time: 9
Output 1:
Taxi-1 is allocated.
Input 2:
Customer ID: 2, Pickup: B, Drop: D, Pickup Time: 9
Output 2:
Taxi-2 is allocated.
Details:
Taxi-1 Total Earnings: Rs.200
BookingID CustomerID From To PickupTime DropTime Amount
1 1 A B 9 10 200Conclusion
This implementation demonstrates effective use of object-oriented principles, logical reasoning, and resource allocation. By encapsulating details in separate classes, the solution remains modular and scalable, making it suitable for real-world applications.
