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Added class and test method for code challenge Matrix Determinant.
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4 files changed

+180
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‎Coderbyte_CSharp/3 Hard Challenges/MatrixDeterminant.cs‎

Lines changed: 157 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,157 @@
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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using System.Threading.Tasks;
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namespace Coderbyte_CSharp.Hard_Challenges
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{
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class Determinant
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{
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// Have the function MatrixDeterminant(strArr) read strArr which will be an
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// array of integers represented as strings.Within the array there will also
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// be "<>" elements which represent break points.The array will make up a
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// matrix where the(number of break points + 1) represents the number of
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// rows.Here is an example of how strArr may look : ["1", "2", "<>", "3", "4"].
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//
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// The contents of this array are row1 = [1 2] and row2 = [3 4]. Your program
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// should take the given array of elements, create the proper matrix, and then
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// calculate the determinant. For the example above, your program should return -2.
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// If the matrix is not a square matrix, return -1. The maximum size of strArr
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// will be a 6x6 matrix.The determinant will always be an integer.
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public int MatrixDeterminant(string[] strArr, int size)
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{
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int determinant = 0;
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List<List<int>> matrix = new List<List<int>>();
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ParseMatrix(strArr, size, ref matrix);
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if (IsSquareMatrix(matrix))
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{
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determinant = ComputeDeterminant(matrix);
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}
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else
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{
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Console.WriteLine("matrix is not square");
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}
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return determinant;
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}
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protected bool IsSquareMatrix(List<List<int>> matrix)
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{
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bool isSquare = true;
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// checking if input matrix is square
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for (int row = 0; row < matrix.Count; row++)
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{
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if (matrix[row].Count != matrix.Count)
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{
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isSquare = false;
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break;
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}
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}
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return isSquare;
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}
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protected void ParseMatrix(string[] strArr, int size, ref List<List<int>> matrix)
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{
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List<int> rowData = new List<int>();
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for (int x = 0; x < size; x++)
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{
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// condition to check for breakpoints
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if (strArr[x] == "<>")
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{
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// Create a separate copy of rowData for matrix
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matrix.Add(new List<int>(rowData));
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rowData.Clear();
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}
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else
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{
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// converting to int
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int value = 0;
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// convert to snippet
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try
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{
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value = Int32.Parse(strArr[x]);
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}
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catch (FormatException e)
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{
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Console.WriteLine("Unable to parse {0}", strArr[x]);
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Console.Error.Write(e.Message);
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}
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// adding to our row
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rowData.Add(value);
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}
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}
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// adding last row
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// Create a separate copy of rowData for matrix
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matrix.Add(new List<int>(rowData));
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}
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protected int ComputeDeterminant(List<List<int>> matrix)
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{
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int determinant = 0;
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if (matrix.Count == 1)
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{
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determinant = matrix[0][0];
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}
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// check for 2-by-2 matrix perform det calculation
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else if (matrix.Count == 2)
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{
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determinant = (matrix[0][0] * matrix[1][1]) - (matrix[0][1] * matrix[1][0]);
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}
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// otherwise determine cofactor, submatrix and recursively compute determinant
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else
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{
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int cofactor = 0;
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// iterate across first row to set cofactor
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for (int p = 0; p < matrix[0].Count; p++)
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{
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// create submatrix
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List<List<int>> subMatrix = new List<List<int>>();
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int matrixSize = matrix.Count;
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for (int i = 1; i < matrixSize; i++)
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{
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// iteration will start from row one cancelling the first row values
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List<int> tempRow = new List<int>();
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for (int j = 0; j < matrixSize; j++)
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{
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// iteration will pass all cells of the i row excluding the j
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//value that match p column
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if (j != p)
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{
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tempRow.Add(matrix[i][j]);//add current cell to TempRow
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}
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}
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// Adding each row to submatrix
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if (tempRow.Count > 0)
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{
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subMatrix.Add(tempRow);
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}
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}
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// recursively calculate the determinant value
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cofactor = matrix[0][p];
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determinant += (int)(Math.Pow(-1, p)) * cofactor * ComputeDeterminant(subMatrix);
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}
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}
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return determinant;
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}
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}
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}

‎Coderbyte_CSharp/Coderbyte_CSharp.csproj‎

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@@ -58,6 +58,7 @@
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<Compile Include="2 Medium Challenges\StringUniqueSubstring.cs" />
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<Compile Include="2 Medium Challenges\TreeGraphs.cs" />
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<Compile Include="3 Hard Challenges\Kaprekar.cs" />
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<Compile Include="3 Hard Challenges\MatrixDeterminant.cs" />
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<Compile Include="Program.cs" />
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<Compile Include="Properties\AssemblyInfo.cs" />
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<Compile Include="TestChallenge.cs" />

‎Coderbyte_CSharp/Program.cs‎

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -31,10 +31,11 @@ static void Main(string[] args)
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tc.Test_MinWindowSubstring();
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tc.Test_RunLength();
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tc.Test_StringReduction();
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tc.Test_TreeConstructor();
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//tc.Test_TreeConstructor();
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// Hard
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tc.Test_KaprekarsConstant();
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tc.Test_Determinant();
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}
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}
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}

‎Coderbyte_CSharp/TestChallenge.cs‎

Lines changed: 20 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -13,7 +13,7 @@ namespace Coderbyte_CSharp
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class TestChallenge
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{
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#region Support Methods
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protected void printArray(int[] arr, int length)
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protected void PrintArray(int[] arr, int length)
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{
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List<int> data = arr.ToList<int>();
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Console.WriteLine();
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}
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protected void printArray(string[] arr, int length)
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protected void PrintArray(string[] arr, int length)
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{
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List<string> data = arr.ToList<string>();
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MathSequence sequence = new MathSequence(); ;
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Console.WriteLine("ArithGeo Sequence:");
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printArray(arr, length);
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PrintArray(arr, length);
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Console.WriteLine("Output: {0}", sequence.ArithGeo(arr, length));
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Console.WriteLine();
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Console.WriteLine("ArithGeo Sequence:");
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printArray(arr, arr.Length);
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PrintArray(arr, arr.Length);
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Console.WriteLine("Output: {0}", numbers.Consecutive(arr, arr.Length));
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Console.WriteLine();
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@@ -294,17 +294,17 @@ public void Test_TreeConstructor()
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string[] strArr = new string[] { "(1,2)", "(2,4)", "(7,2)" };
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Console.WriteLine("Tree Constructor:");
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printArray(strArr, strArr.Length);
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PrintArray(strArr, strArr.Length);
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Console.WriteLine("Output: {0}", tree.TreeConstructor(strArr, strArr.Length));
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Console.WriteLine();
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string[] strArr2 = new string[] { "(1,2)", "(9,2)", "(2,4)", "(7,2)" };
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printArray(strArr2, strArr2.Length);
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PrintArray(strArr2, strArr2.Length);
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Console.WriteLine("Output: {0}", tree.TreeConstructor(strArr2, strArr2.Length));
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Console.WriteLine();
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string[] strArr3 = new string[] { "(1,2)", "(2,4)", "(5,7)", "(7,2)", "(9,5)" };
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printArray(strArr3, strArr3.Length);
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PrintArray(strArr3, strArr3.Length);
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Console.WriteLine("Output: {0}", tree.TreeConstructor(strArr3, strArr3.Length));
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Console.WriteLine();
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}
@@ -320,6 +320,19 @@ public void Test_KaprekarsConstant()
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Console.WriteLine("Input: {0} ", value);
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Console.WriteLine("Output: {0}", k.KaprekarsConstant(value));
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Console.WriteLine();
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}
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public void Test_Determinant()
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{
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Determinant d = new Determinant();
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string[] array = new string[] { "1", "4", "3", "<>", "2", "3", "0", "<>", "5", "-3", "4" };
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int det;
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det = d.MatrixDeterminant(array, array.Length);
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PrintArray(array, array.Length);
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Console.WriteLine("Output: {0}", d.MatrixDeterminant(array, array.Length));
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Console.WriteLine();
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}
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#endregion

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