/**
* @method Obtain the list of buyer names that have bought a maximum ticket order over several years.
* @params None
* @returns A list of all buyer names in this database representing buyers who have bought the maximum number of allowable tickets over several years.
*/
public HashSet <string> GetAffluentBuyerNames()
{
Dictionary <string, int> fullPurchasesByBuyerName = new Dictionary <string, int>();
// Iterate through all year and all buyers in all years.
foreach (string yearNumber in YearNumbers)
{
Year year = GetYear(yearNumber);
foreach (string buyerName in year.BuyerNames)
{
// Did this buyer buy the maximum number of tickets?
if (year.GetBuyer(buyerName).HadFullAdultTicketOrder(yearNumber))
{
// Add this user to our working dictionary.
if (!fullPurchasesByBuyerName.ContainsKey(buyerName))
{
fullPurchasesByBuyerName[buyerName] = 0;
}
++fullPurchasesByBuyerName[buyerName];
}
}
}
// Count the number of buyers who have maxed out their ticket orders across several years.
HashSet <string> affluentBuyerNames = new HashSet <string>();
foreach (string buyerName in fullPurchasesByBuyerName.Keys)
{
if (fullPurchasesByBuyerName[buyerName] >= _configuration.GetAffluentBuyerYearThreshold())
{
affluentBuyerNames.Add(buyerName);
}
}
return(affluentBuyerNames);
}