Need help with Java Answer

[alexisasoxfan]

So I have the following classes that both work.

The Time Class

public class Time
{
    // instance variables - replace the example below with your own
    private int hours;
    private int minutes;

    /**
     * Constructor for objects of class Time
     */
    
    public Time(int h, int m)
    {
        // initialise instance variables
        hours = h;
        minutes = m;
    }
    
    public void setTime (int h, int m) {
        
        hours = h;
        minutes = m;
        
    }
    
    public int getHours() {
     
        return hours;
        
    }
    
    public int getMinutes() {
        
        return minutes;
        
    }
    
    public boolean isValidTime() {
       
       if ((hours >= 0 && hours <= 23) && (minutes >= 0 &&  minutes <= 59)) {
           return true;
        } else {
         
            return false;
            
        }
        
    }
    
    public String toString() {
        
        
        return hours + ":" + minutes;
        
    }
    
    public int minutesUntil (Time other) {
        
        int x = (this.hours * 60) + this.minutes;
        int y = 1440 - x;
     
        
        int a = (other.hours * 60) + other.minutes;
        int b = 1440 - a;
        
        return y - b;
    }
        
}

The Flight Class

public class Flight
{
    // instance variables - replace the example below with your own
    private String num;
    private Time departure;
    private Time arrival;

    /**
     * Constructor for objects of class Flight
     */
    public Flight(String f, Time d, Time a)
    {       
        num = f;
        departure = d;
        arrival = a;

    }
    
    public void setFlight (String f, Time d, Time a) {
        num = f;
        departure = d;
        arrival = a;
    }
    
    public Time getDepartureTime() {
     
        return departure;
        
    }
    
    public Time getArrivalTime() {
        
        return arrival;
        
    }
    
     public String toString() {
       
         int x = departure.getHours();
         int a = arrival.getHours();
         int test =  (x - a) * 60;
         int test_2 = test + (departure.getMinutes() - arrival.getMinutes());
         
        return num + "-" + departure + "-" + arrival + "-" + test_2;
        
    }

}

The Trip Class

import java.util.*;

    public class Trip  {

    private String time;
    private ArrayList<Flight> a;

    public Trip (String t, ArrayList<Flight> f) {

        time = t;
        a = f;

    }
    
    public int getDuration () {
        
        // Need help with this method
     
    } 
    
}

I need help completing the getDuration method.
The getDuration method returns the number of minutes, from the departure of the first flight to the arrival of the last flight.

I'm not sure how to do this. Thanks for any help I can get.

[alexisasoxfan]

I was thinking about using the arraylist function get, but I'm not sure.

[m00nchile]

If the flights in the arraylist are already sorted, you just need to do this:

public int getDuration() {
  Time t1 = a.get(0).getDepartureTime();
  Time t2 = a.get(a.size()-1).getArrivalTime();
  return t1.minutesUntil(t2);
}

If the flights are not sorted, then you first need to find the earliest departure and the latest arrival time in your array, the return statement remains the same.