mapid: List<characterid, donation_amount>

Map Id       Character Id       Amount
100000            3             100000
110000            4             200000
100000            5              10000
110000            6             100000
200000            7                  0

public void loadDonations() {
    try (PreparedStatement ps = DatabaseConnection.getConnection().prepareStatement("SELECT * FROM medal_rankings ORDER BY donated DESC");
         ResultSet rs = ps.executeQuery()) {

        while (rs.next()) {
            int mapid       = rs.getInt("mapid");
            int characterid = rs.getInt("characterid");
            int donated     = rs.getInt("donated");

            if (!donations.containsKey(mapid))
                donations.put(mapid, new ArrayList<Pair<Integer, Integer>>());
            donations.get(mapid).add(new Pair<Integer, Integer>(characterid, donated));
        }
    } catch (Exception e) {
        e.printStackTrace();
        LogHelper.INVOCABLE.get().info("DonorKing: failed to load donations");
    }
}

public void addDonation(int amount, int mapid, int characterid) {
    List<Pair<Integer, Integer>> map_donations = donations.get(mapid);
    if (!donations.containsKey(mapid))
        donations.put(mapid, new ArrayList<Pair<Integer, Integer>>());
    if (!map_donations.contains(characterid))
        map_donations.add(new Pair<Integer, Integer>(characterid, amount));
    else {
        for (int x = 0; x < map_donations.size(); x++) {
            List<Pair<Integer, Integer>> donation = map_donations;
            if (donation.get(x).left == characterid) {
                amount += donation.get(x).right;
                donation.remove(donation.get(x));
                break;
            }
        }

        for (int x = 0; x < map_donations.size(); x++)
            if (map_donations.get(x).right <= amount) {
                map_donations.add(new Pair<Integer, Integer>(characterid, amount));
                break;
            }
    }
}