protected override MaxSubArray Search(int[] values, int start, int end)
{
var max = new MaxSubArray(0, 0, 0);
for (var i = 0; i < values.Length; i++)
{
var currentSum = 0;
var currentMax = 0;
var currentMaxStart = i;
for (var j = i; j >= 0; j--)
{
currentSum += values[j];
if (currentSum <= 0) break; // An opportunity to break out early as a negative/zero value indicates that any gains in this sub-array have already been wiped out
if (currentSum > currentMax)
{
currentMax = currentSum;
currentMaxStart = j;
}
}
if (currentMax > max.Sum)
{
max.Sum = currentMax;
max.Start = currentMaxStart;
max.End = i + 1;
}
}
return max;
}
private static MaxSubArray FindMaxSubarray(int[] a, int low, int high)
{
var res = new MaxSubArray {
Low = low,
High = high,
Sum = a[low]
};
if (low == high)
{
return(res);
}
var mid = (low + high) / 2;
var leftSubarray = FindMaxSubarray(a, low, mid);
var rightSubarray = FindMaxSubarray(a, mid + 1, high);
var crossingSubarray = FindMaxCrossingSubarray(a, low, mid, high);
if (leftSubarray.Sum >= rightSubarray.Sum &&
leftSubarray.Sum >= crossingSubarray.Sum)
{
return(leftSubarray);
}
if (rightSubarray.Sum >= leftSubarray.Sum &&
rightSubarray.Sum >= crossingSubarray.Sum)
{
return(rightSubarray);
}
return(crossingSubarray);
}
public void Test()
{
int[] items = { 13, -3, -25, 20, -3, -16, -23, 18, 20, -7, 12, -5, -22, 15, -4, 7 };
//int[] items = { -13, -3, -25, -20, -3, -16, -23, -18, -20, -7, -12, -5, -22, -15, -4, -7 };
var result2 = new MaxSubArray3().FindMaximumSubArray(items, 0, items.Length - 1);
var result = new MaxSubArray().FindMaximumSubArray(items, 0, items.Length - 1);
}
public void MaxSubArrayTest1()
{
int[] array = new int[] { -2, 1, -3, 4, -1, 2, 1, -5, 4 };
MaxSubArray ms = new MaxSubArray();
int actual = ms.Max(array);
int expected = 6;
Assert.AreEqual(actual, expected);
}
static void TestMaxSubArraySoln()
{
Console.WriteLine(" ***** MaxSubArray Solutions Test ***** ");
int[] sampleAAA = { 13, -3, -25, 20, -3, -16, -23, 18, 20, -7, 12, -5, -22, 15, -4, 7 };
CollectionToString CtoS = new CollectionToString();
MaxSubArray MSA = new MaxSubArray();
Console.WriteLine("Brute sum result: {0}", MSA.BruteForceMax(sampleAAA));
Console.WriteLine("Brute start array result: {0}", MSA.BruteForceStartPos(sampleAAA));
}
public void Excution1Test()
{
var func = new MaxSubArray();
Assert.AreEqual(6, func.Excution1(new[] { -2, 1, -3, 4, -1, 2, 1, -5, 4 }));
Assert.AreEqual(0, func.Excution1(new int[] { }));
Assert.AreEqual(-2, func.Excution1(new int[] { -2 }));
Assert.AreEqual(-1, func.Excution1(new int[] { -2, -1, -3 }));
Assert.AreEqual(5, func.Excution1(new int[] { 5, -2, -1, -3, 1 }));
}
public void GetTest()
{
var source = new[] { -2, -3, 4, -1, -2, 1, 5, -3 };
var target = new MaxSubArray();
var results = target.Get(source);
Assert.AreEqual(7, results.Key);
Assert.AreEqual(2, results.Value[0]);
Assert.AreEqual(6, results.Value[1]);
source = new[] { -1, -2, -3, 4, 5, -10, -1 };
results = target.Get(source);
Assert.AreEqual(9, results.Key);
Assert.AreEqual(3, results.Value[0]);
Assert.AreEqual(4, results.Value[1]);
}
private static void callMaxSubArray()
{
MaxSubArray prb = new MaxSubArray();
Console.WriteLine(prb.GetMaxSubArrayDC(new int[] { -2, 3, 0, 2, -2, 3 }));
}
void BaseTest(Type type, MaxSubArray expected, params int[] values)
{
var searcher = Activator.CreateInstance(type) as ISearcher;
var r = searcher.Search(values);
Assert.AreEqual(expected.Start, r.Start, "Start index differs");
Assert.AreEqual(expected.End, r.End, "End index differs");
Assert.AreEqual(expected.Sum, r.Sum, "Sum value differs");
}
