/// <summary>
/// Read multiple sorted streams and merge their contents in sorted order.
/// </summary>
/// <param name="streamNames">The stream names to read from.</param>
/// <param name="priorityQueue">The Index Priority Queue to use for merging.</param>
/// <param name="expectedItems">The expected results.</param>
/// <remarks>
/// This method expects each input stream to be sorted but does not verify it.
/// If the inputs are unsorted the results will be incorrect.
/// </remarks>
public static void MergeMultiWay(string[] streamNames, IndexPQDictionary<string> priorityQueue, Queue<string> expectedItems)
{
In[] inputStream = new In[streamNames.Length];
try
{
for (int i = 0; streamNames.Length > i; i++)
{
inputStream[i] = new In(streamNames[i]);
priorityQueue.Enqueue(i, inputStream[i].ReadString());
}
// Extract and print min and read next from its stream.
while (0 != priorityQueue.Count)
{
string actualItem = priorityQueue.PeekPriority();
string expectedItem = expectedItems.Dequeue();
Assert.AreEqual(expectedItem, actualItem);
int i = priorityQueue.Dequeue();
if (!inputStream[i].IsEmpty())
{
priorityQueue.Enqueue(i, inputStream[i].ReadString());
}
}
}
finally
{
for (int i = 0; streamNames.Length > i; i++)
{
inputStream[i].Close();
}
}
}
/// <summary>
/// Test that de-queue behavior on an index PQ is the same as a regular queue.
/// </summary>
/// <param name="testItems">The stream from where the input strings will be read.</param>
/// <param name="priorityQueue">The queue to operate on.</param>
/// <param name="expectedItems">The expected items.</param>
public static void DequeuePQTest(string[] testItems, IndexPQDictionary<string> priorityQueue, Queue<string> expectedItems)
{
for (int i = 0; i < testItems.Length; i++)
{
priorityQueue.Enqueue(i, testItems[i]);
}
// Compare dequeueing
while (0 != priorityQueue.Count)
{
Assert.AreEqual(priorityQueue.Count, expectedItems.Count);
string actualItem = testItems[priorityQueue.Dequeue()];
string expectedItem = expectedItems.Dequeue();
Assert.AreEqual(expectedItem, actualItem);
}
}
/// <summary>
/// Test that enumerator behavior on an index PQ is the same as a regular queue.
/// </summary>
/// <param name="testItems">The stream from where the input strings will be read.</param>
/// <param name="priorityQueue">The queue to operate on.</param>
/// <param name="expectedItems">The expected items.</param>
public static void EnumerationPQTest(string[] testItems, IndexPQDictionary<string> priorityQueue, Queue<string> expectedItems)
{
for (int i = 0; i < testItems.Length; i++)
{
priorityQueue.Enqueue(i, testItems[i]);
}
Assert.AreEqual(priorityQueue.Count, expectedItems.Count);
foreach (KeyValuePair<int, string> kvp in priorityQueue)
{
string actualItem = kvp.Value;
string expectedItem = expectedItems.Dequeue();
Assert.AreEqual(expectedItem, actualItem);
}
// Enumeration should be non-destructive (as opposed to de-queueing)
Assert.AreEqual(testItems.Length, priorityQueue.Count);
}
