public void MaxLimitHeap_Works_Correctly(int heapSize, int itemCount)
{
var items = new string[itemCount];
for (var i = 0; i < itemCount; i++)
{
items[i] = Guid.NewGuid().ToString("N");
}
var heap = new MaxLimitHeap <string>(heapSize);
Assert.AreEqual(heap.AddAll(items), itemCount);
Array.Sort(items);
Array.Reverse(items);
var minItems = new HashSet <string>();
var itemCounter = 0;
for (var i = 0; i < Math.Min(heapSize, itemCount); i++)
{
minItems.Add(items[itemCounter++]);
}
itemCounter = 0;
foreach (var current in heap.PopAll())
{
Assert.IsTrue(minItems.Contains(current));
itemCounter++;
}
Assert.AreEqual(itemCounter, Math.Min(heapSize, itemCount));
}
/// <summary>
/// Enumerates over given <paramref name="itemCollection"/> and finds the
/// maximums (up to <paramref name="totalMaximums"/>) items using <paramref name="comparer"/>.
/// Returns another enumerable based of required <paramref name="sorting"/>.
/// </summary>
/// <typeparam name="T">Type of the items in the input collection</typeparam>
/// <param name="itemCollection">Input collection</param>
/// <param name="totalMaximums">Count of total number of maximum to find.
/// Error is thrown if value is negative or zero (0).</param>
/// <param name="comparer">Comparer instance. If not provided, then <seealso cref="Comparer{T}.Default"/> will be used.</param>
/// <param name="sorting">Output sorting (it uses <paramref name="comparer"/>). As the interest is only to find all the required
/// number of maximums. It is best to use <seealso cref="SortOrder.None"/> as sorting value
/// otherwise, an additional latency might be observed.</param>
public static IEnumerable <T> FindMaximums <T>(this IEnumerable <T> itemCollection,
int totalMaximums,
IComparer <T> comparer = null,
SortOrder sorting = SortOrder.None)
{
var heap = new MaxLimitHeap <T>(totalMaximums, comparer);
heap.AddAll(itemCollection);
return(heap.GetSorted(comparer, sorting, true));
}