A group of NP (2 ≤ NP ≤ 10) uniquely named friends has decided to exchange gifts of money. Each of these friends might or might not give some money to some or all of the other friends (although some might be cheap and give to no one). Likewise, each friend might or might not receive money from any or all of the other friends. Your goal is to deduce how much more money each person receives than they give.
The rules for gift-giving are potentially different than you might expect. Each person goes to the bank (or any other source of money) to get a certain amount of money to give and divides this money evenly among all those to whom he or she is giving a gift. No fractional money is available, so dividing 7 among 2 friends would be 3 each for the friends with 1 left over – that 1 left over goes into the giver’s “account”. All the participants’ gift accounts start at 0 and are decreased by money given and increased by money received.
In any group of friends, some people are more giving than others (or at least may have more acquaintances) and some people have more money than others.
Given:
Important Note The grader machine is a Linux machine that uses standard Unix conventions: end of line is a single character often known as ‘\n’. This differs from Windows, which ends lines with two characters, ‘\r\ and ‘\n’. Do not let your program get trapped by this!
Line # | Contents
———-|———
1 | A single integer, NP
2..NP+1 | Line i+1 contains the name of group member i
NP+2..end | NP groups of lines organized like this:
The first line of each group tells the person’s name who will be giving gifts.
The second line in the group contains two numbers:
- The amount of money (in the range 0..2000) to be divided into gifts by the giver
- NGi (0 ≤ NGi ≤ NP), the number of people to whom the giver will give gifts
If NGi is nonzero, each of the next NGi lines lists the name of a recipient of a gift; recipients are not repeated in a single giver’s list.
5
dave
laura
owen
vick
amr
dave
200 3
laura
owen
vick
owen
500 1
dave
amr
150 2
vick
owen
laura
0 2
amr
vick
vick
0 0
The output is NP lines, each with the name of a person followed by a single blank followed by the net gain or loss (final_money_value - initial_money_value) for that person. The names should be printed in the same order they appear starting on line 2 of the input.
All gifts are integers. Each person gives the same integer amount of money to each friend to whom any money is given, and gives as much as possible that meets this constraint. Any money not given is kept by the giver.
dave 302
laura 66
owen -359
vick 141
amr -150
Five names: dave, laura, owen, vick, amr. Let’s keep a table of the gives (money) each person ‘has’:
dave laura owen vick amr
0 0 0 0 0
First, ‘dave’ splits 200 among ‘laura’, ‘owen’, and ‘vick’. That comes to 66 each, with 2 left over:
-200+2 +66 +66 +66 0
→
-198 66 66 66 0
Second, ‘owen’ gives 500 to ‘dave’:
-198+500 66 66-500 66 0
→
302 66 -434 66 0
Third, ‘amr’ splits 150 between ‘vick’ and ‘owen’:
302 66 -434+75 66+75 -150
→
302 66 -359 141 -150
Fourth, ‘laura’ splits 0 between ‘amr’ and ‘vick’; no changes:
302 66 -359 141 -150
Finally, ‘vick’ gives 0 to no one:
dave laura owen vick amr
302 66 -359 141 -150
This is a very straight forward problem. To help us keep track of the details, we create a People object. Then, it’s just a matter of following the gift-giving rules and outputting the results.
public class gift1 {
public static void main(String[] args) throws IOException {
try (final BufferedReader f = new BufferedReader(new FileReader("gift1.in"));
final PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("gift1.out")))) {
// parse the number of people in the group
final int NP = Integer.parseInt(f.readLine());
// parse the people in the group
final List<Person> group = new ArrayList<>(NP);
final Map<String, Person> groupMap = new HashMap<>();
for (int i = 0; i < NP; i++) {
final String name = f.readLine();
final Person person = new Person(name);
group.add(person);
groupMap.put(name, person);
}
// parse the details for each person in the group
for (int i = 0; i < NP; i++) {
final Person person = groupMap.get(f.readLine());
final String line = f.readLine();
final String[] tokens = line.split(" ");
person.amountToGive = Integer.parseInt(tokens[0]);
final int numberOfFriends = Integer.parseInt(tokens[1]);
for (int j = 0; j < numberOfFriends; j++) {
person.addFriend(groupMap.get(f.readLine()));
}
}
// exchange gifts
for (Person person : group) {
if (person.getNumberOfFriends() > 0) {
// distribute gifts to friends
final int giftAmount = person.amountToGive / person.getNumberOfFriends();
final int remainder = person.amountToGive % person.getNumberOfFriends();
person.distributeGifts(giftAmount);
person.addAccount(remainder);
} else {
// no gifts to give; keep the money
person.addAccount(person.amountToGive);
}
}
// output results
for (Person person : group) {
out.print(person.name);
out.print(" ");
out.println(person.account - person.amountToGive);
}
}
}
public static class Person {
String name;
int account;
int amountToGive;
final private List<Person> friends;
private Person() {
super();
friends = new ArrayList<>();
}
Person(String name) {
this();
this.name = name;
}
void addAccount(int amount) {
account += amount;
}
void addFriend(Person person) {
friends.add(person);
}
int getNumberOfFriends() {
return friends.size();
}
void distributeGifts(int giftAmount) {
for (Person friend : friends) {
friend.addAccount(giftAmount);
}
}
}
}
Link To: Java Source Code