static void Main()
{
int reps = 5000000;
Console.WriteLine("LINQ's Last extension method will enumerate over the *entire* collection giving");
Console.WriteLine("a time complexity of O(n) regardless of the data structure. This is due to the");
Console.WriteLine("\"one size fits all\" approach of LINQ. SortedDictionary supplies no optimized");
Console.WriteLine("implementation of Last. Also, SortedDictionary does not supply any optimized");
Console.WriteLine("way of performing queries based on a key range. Again, the time complexity of");
Console.WriteLine("such an operation is O(n).\n");
var sd = new SortedDictionary <int, int>();
Console.Write("Loading SortedDictionary with " + reps + " elements:\n\nLoad time = ");
Stopwatch watch1 = new Stopwatch();
watch1.Reset();
watch1.Start();
for (int i = 0; i < reps; ++i)
{
sd.Add(i, -i);
}
var time11 = watch1.ElapsedMilliseconds;
var last1 = sd.Last();
var time12 = watch1.ElapsedMilliseconds;
Console.WriteLine(time11 + "ms");
Console.WriteLine("Last time = " + (time12 - time11) + "ms");
////
Console.WriteLine("\nRankedDictionary has its own implementation of Last() which does not suffer the");
Console.WriteLine("performance hit that SortedDictionary.Last() does. RankedDictionary also");
Console.WriteLine("supports optimized range queries with its ElementsFrom(TKey) and");
Console.WriteLine("ElementsBetween(TKey,TKey) enumerators.\n");
var bt = new RankedDictionary <int, int>();
Console.Write("Loading RankedDictionary with " + reps + " elements:\n\nLoad time = ");
Stopwatch watch2 = new Stopwatch();
watch2.Reset();
watch2.Start();
for (int i = 0; i < reps; ++i)
{
bt.Add(i, -i);
}
var time21 = watch2.ElapsedMilliseconds;
var lastKV = bt.Last();
var time22 = watch2.ElapsedMilliseconds;
// Range query: Sum the middle 100 values.
var rangeVals = bt.ElementsBetween(reps / 2 - 50, reps / 2 + 50).Sum(x => x.Value);
var time23 = watch2.ElapsedMilliseconds;
Console.WriteLine(time21 + "ms");
Console.WriteLine("Last time = " + (time22 - time21) + "ms");
Console.WriteLine("Range time = " + (time23 - time22) + "ms");
#if DEBUG
bt.SanityCheck();
Console.WriteLine();
Console.Write("---- height = " + bt.GetHeight());
Console.Write(", branch fill = " + bt.BranchSlotsUsed * 100 / bt.BranchSlotCount + "%");
Console.WriteLine(", leaf fill = " + bt.LeafSlotsUsed * 100 / bt.LeafSlotCount + "% ----");
#endif
}
static void Main()
{
int reps = 10000000;
var sl = new SortedList <int, int>();
var rd = new RankedDictionary <int, int>();
var watch = new Stopwatch();
Console.WriteLine("Loading SortedList...");
for (int ix = 0; ix <= reps; ++ix)
{
sl.Add(ix, -ix);
}
Console.WriteLine("Loading RankedDictionary...");
for (int i = 0; i <= reps; ++i)
{
rd.Add(i, -i);
}
Thread.Sleep(500);
Console.WriteLine("Get Element at Index");
Console.WriteLine("Time in Milliseconds");
Console.WriteLine("Index by " + (reps / 10));
Console.WriteLine("Count;row;SortedList;RankedDictionary");
for (int row = 0, ix = 0; ix <= reps; ix += reps / 10)
{
watch.Reset(); watch.Start();
var slPair = sl.ElementAt(ix);
var slTime = watch.ElapsedMilliseconds;
if (slPair.Key != -slPair.Value)
{
Console.Write("FAIL");
}
watch.Reset(); watch.Start();
var rdPair = rd.ElementAt(ix);
var rdTime = watch.ElapsedMilliseconds;
if (rdPair.Key != -rdPair.Value)
{
Console.Write("FAIL");
}
var lx = String.Format($"{ix,9};{row,4};{slTime,5};{rdTime,5}");
if (row > 0)
{
Console.WriteLine(lx);
}
++row;
}
watch.Reset(); watch.Start();
var slPair2 = sl.Last();
var slTime2 = watch.ElapsedMilliseconds;
if (slPair2.Key != -slPair2.Value)
{
Console.Write("FAIL");
}
watch.Reset(); watch.Start();
var rdPair2 = rd.Last();
var rdTime2 = watch.ElapsedMilliseconds;
if (rdPair2.Key != -rdPair2.Value)
{
Console.Write("FAIL");
}
var lx2 = String.Format($"{reps,9};Last;{slTime2,5};{rdTime2,5}");
Console.WriteLine(lx2);
}