private static MaxSubarrayResult SolveRecursive(int[] data, int lowIndex, int highIndex)
{
if (lowIndex == highIndex)
{
return new MaxSubarrayResult {
MaxSum = data[lowIndex], StartIndex = lowIndex, EndIndex = lowIndex
}
}
;
int midIndex = (lowIndex + highIndex) / 2;
MaxSubarrayResult leftResult = SolveRecursive(data, lowIndex, midIndex);
MaxSubarrayResult rightResult = SolveRecursive(data, midIndex + 1, highIndex);
MaxSubarrayResult midResult = SolveMid(data, lowIndex, midIndex, highIndex);
if (leftResult.MaxSum >= rightResult.MaxSum && leftResult.MaxSum >= midResult.MaxSum)
{
return(leftResult);
}
else if (rightResult.MaxSum >= leftResult.MaxSum && rightResult.MaxSum >= midResult.MaxSum)
{
return(rightResult);
}
else
{
return(midResult);
}
}
public override bool Equals(object other)
{
MaxSubarrayResult otherResult = other as MaxSubarrayResult;
if (otherResult == null)
{
return(false);
}
return(this.MaxSum == otherResult.MaxSum);
}
public static void TestSpeed()
{
for (int size = 1; size <= 400; size++)
{
//Console.Write("Element count = ");
//string text = Console.ReadLine();
int elementCount = size; // int.Parse(text);
int repeatCount = 12;
int minValue = -100;
int maxValue = 100;
Random random = new Random();
for (int repeatIndex = 0; repeatIndex < repeatCount; repeatIndex++)
{
int[] data = new int[elementCount];
for (int elemIndex = 0; elemIndex < elementCount; elemIndex++)
{
data[elemIndex] = random.Next(minValue, maxValue);
}
//string dataStr = string.Join(", ", data);
//Debug.Print(dataStr);
MaxSubarrayResult resultBruteForce = RunWithSpeedDetails(SolveBruteForce, data, "brute force");
MaxSubarrayResult resultRecursive = RunWithSpeedDetails(SolveRecursive, data, "recursive");
MaxSubarrayResult resultLinear = RunWithSpeedDetails(SolveLinear, data, "linear");
Debug.Assert(resultRecursive.Equals(resultLinear));
Debug.Assert(resultRecursive.Equals(resultBruteForce));
string file = @"C:\Temp\MaxSubarray.csv";
string fieldDelim = ";";
string line = $"{data.Length}{fieldDelim}{resultBruteForce.TimeElapsed}{fieldDelim}{resultRecursive.TimeElapsed}{fieldDelim}{resultLinear.TimeElapsed}";
if (!File.Exists(file))
{
File.AppendAllLines(file, new[] { $"Elems{fieldDelim}Brute force{fieldDelim}Recursive{fieldDelim}Linear" });
}
File.AppendAllLines(file, new[] { line });
Debug.Print("");
}
}
}
static MaxSubarrayResult RunWithSpeedDetails(Func <int[], MaxSubarrayResult> func, int[] data, string funcName)
{
Stopwatch sw = Stopwatch.StartNew();
MaxSubarrayResult result = func(data);
result.TimeElapsed = sw.ElapsedTicks;
string text = $"max: {result.MaxSum}, {result.StartIndex} - {result.EndIndex}";
//Debug.Print(text);
Debug.Print($"{data.Length} items {funcName}: {result.TimeElapsed} ticks");
return(result);
}