Last Updated: February 25, 2016
· saurabhksingh

Algorithm : Trip expense management

A group of students are members of a club that travels annually to different lo-
cations. Their destinations in the past have included Indianapolis, Phoenix, Nashville,
Philadelphia, San Jose, and Atlanta. This spring they are planning a trip to Eindhoven.
The group agrees in advance to share expenses equally, but it is not practical to share
every expense as it occurs. Thus individuals in the group pay for particular things, such
as meals, hotels, taxi rides, and plane tickets. After the trip, each student’s expenses
are tallied and money is exchanged so that the net cost to each is the same, to within
one cent. In the past, this money exchange has been tedious and time consuming. Your
job is to compute, from a list of expenses, the minimum amount of money that must
change hands in order to equalize (within one cent) all the students’ costs.

Input :
Standard input will contain the information for several trips. Each trip consists of a
line containing a positive integer n denoting the number of students on the trip. This is
followed by n lines of input, each containing the amount spent by a student in dollars
and cents. There are no more than 1000 students and no student spent more than
$10,000.00. A single line containing 0 follows the information for the last trip.

Output :
For each trip, output a line stating the total amount of money, in dollars and cents,
that must be exchanged to equalize the students’ costs.
Sample Input
Step 1 will be to calculate the mean of all expenses. Now anyone who spends more than the mean amount will have to be compensated by the people spent more than the mean amount. So the total amount to required by people ho spent more than mean will be the sum of difference between the amount they spent and the mean amount.
Below is the code for the same :

import java.util.ArrayList;
import java.util.List;

public class TripExpense {
* @param args
* @throws IOException
public static void main(String[] args) throws IOException {

    BufferedReader br = new BufferedReader(new InputStreamReader(;
    String input = "";
    //read the input from the console
    while ((input = br.readLine()) != null && !input.trim().equals("\n") && !input.trim().equals(""))
        int numberOfPeople = Integer.parseInt(input);

        if (numberOfPeople == 0)
        double [] expenses = new double [numberOfPeople];

        double sum  = 0;
        for(int i=0; i<numberOfPeople; i++)
            input = br.readLine();
            expenses [i] = Double.parseDouble(input);
            sum += expenses[i];

        double avgExpense = sum/numberOfPeople;

        sum = 0;

        for (double expense : expenses)
            if((avgExpense - expense) > 0.01)
                sum += (avgExpense - expense);