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how to insert a new value in a two dimensional array?

I have a 10x10 matrix that I am filling with random chars. My problem is that I can't figure out how to insert a string "HOUSE" into the first row of the table.
Random rchar = new Random();
string word = "HOUSE";
char[] wordChars = word.ToCharArray();
char[,] arr = new char[10, 10];
//Size of Rows and Cols
var rowLength = arr.GetLength(0);
var colLength = arr.GetLength(1);
for (int x = 0; x < rowLength; x++)
{
for (int y = 0; y < colLength; y++)
{
arr[0, y] = wordChars[1];
arr[x, y] = (char)(rchar.Next(65, 91));
Console.Write(arr[x, y] + " ");
}
Console.WriteLine();
}
I was trying to place a new value with the SetValue property but it doesn't work for me because I have a two-dimensional array.

Just set to your arr using two dimentional indices like [1,1] or [x,y]
Example:
public static void Main()
{
Random rchar = new Random();
char[,] arr = new char[10, 10];
//Size of Rows and Cols
var rowLength = arr.GetLength(0);
var colLength = arr.GetLength(1);
for (int x = 0; x < rowLength; x++)
{
for (int y = 0; y < colLength; y++)
{
arr[x,y] = (char)(rchar.Next(65, 91));
Console.Write(arr[x, y] + " ");
}
Console.WriteLine();
}
}

Try running this piece of code, I think it covers your question of setting values in a multidimensional array.
Also I see a "chars[1]" in your code, this variable does not exist, did you mean to get the random char here?
You might want to look up how to get a random char and put it in that spot.
char[,] arr = new char[10, 10];
arr[0, 0] = 'a';
arr[0, 1] = 'b';
arr[0, 2] = 'c';
arr[1, 0] = 'd';
arr[1, 1] = 'e';
arr[1, 2] = 'f';
for (int i = 0; i < 3; i++)
{
Console.WriteLine(arr[0, i]);
}
for (int i = 0; i < 3; i++)
{
Console.WriteLine(arr[1, i]);
}

LCS C# Algorithm - Get the deleted lines and added lines in previous and current text

I have to rewrite the LCS algorithm because some company policies.
I've already get done the LCS algorithm, but next step is to identify which lines were removed from the previous text and which one were added in the current text.
I tried a simple check thought the lines, but it won't work if I got a text with duplicated lines.
He is my code:
LCS Method
private static string[] LcsLineByLine(string previous, string current)
{
string[] Previous = previous.Split(new string[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries);
string[] Current = current.Split(new string[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries);
string lcsResult = string.Empty;
int a = Previous.Length;
int b = Current.Length;
int[,] table = new int[a + 1, b + 1];
//create a table with first line and column equal 0
for (int i = 0; i <= a; i++)
table[i, 0] = 0;
for (int j = 0; j <= b; j++)
table[0, j] = 0;
//create a table matrix
for (int i = 1; i <= a; i++)
{
for (int j = 1; j <= b; j++)
{
if (string.Equals(Previous[i - 1].Trim(), Current[j - 1].Trim(), StringComparison.InvariantCultureIgnoreCase))
{
table[i, j] = table[i - 1, j - 1] + 1;
}
else
{
table[i, j] = Math.Max(table[i, j - 1], table[i - 1, j]);
}
}
}
//get the lcs string array with the differences
int index = table[a, b];
string[] lcs = new string[index + 1];
lcs[index] = "0";
while (a > 0 && b > 0)
{
if (string.Equals(Previous[a - 1].Trim(), Current[b - 1].Trim(), StringComparison.InvariantCultureIgnoreCase))
{
lcs[index - 1] = Previous[a - 1].Trim();
a--;
b--;
index--;
}
else if (table[a - 1, b] > table[a, b - 1])
a--;
else
b--;
}
return lcs;
}
And this is the code that is not working with duplicated lines with same value.
Method to get all deleted items in the previous text:
private List<DiffItem> GetDiffPrevious(string[] previous, string[] diff)
{
List<DiffItem> differences = new List<DiffItem>();
//check items deleted
int line = 0;
for (int i = 0; i < previous.Length; i++)
{
bool isAbsent = false;
for (int j = 0; j < diff.Length; j++)
{
if (string.Equals(previous[i].Trim(), diff[j].Trim(), StringComparison.InvariantCultureIgnoreCase))
{
differences.Add(new DiffItem() { Position = line, Text = diff[j], Status = DiffStatus.Equal });
line++;
isAbsent = false;
break;
}
else
{
isAbsent = true;
}
}
//mark as deleted
if (isAbsent)
{
differences.Add(new DiffItem() { Position = line, Text = previous[i].Trim(), Status = DiffStatus.Deleted });
line++;
}
}
return differences;
}
If anyone could help me or any feedback would be great. Just a reminder, I cannot use third party libraries.
Thanks in advance.

I found the solution!
Basically, I rewrite the two lists and translated using Hashtable, so all the values will be unique by line. Then, I use the method LCS and got the result as expected.
I hope it helps somebody.

filling the array with a random number, from 0 to 2, but so that the opposite cell is filled depending on the condition

Working on a grading model, but stuck on filling an array.
I need to fill the array with numbers from 0 to 2, but:
- so that the main diagonal is filled only 1;
- if, for example, the element a (31) = 2, then a (13) must be 0, and a set of;
- if for example the element a (31) = 1, then a (13) must be 1, and a set of;
The principle itself, I understand.
if (array[i+1,j] = 2)
{
(array[i, j+1] = 1)
}
it's wrong i know
for now i have
int[,] array = new int[5, 5];
Random rnd = new Random();
for (int i = 0; i < 5; i++)
{
for (int j = 0; j < 5; j++)
{
array[i, j] = rnd.Next(0, 3);
if (i == j)
{
array[i, j] = 1;
}
}
}
for (int i = 0; i < 5; i++)
{
for (int j = 0; j < 5; j++)
{
Console.Write("{0}\t", array[i, j]);
}
Console.WriteLine();
}
here more detailes

Please check does this work for you(hope understood task correctly):
var arr = new int[4, 4];
var rnd = new Random();
var length = arr.GetLength(0);
for (var i = 0; i < length; i++)
{
for (var j = i; j < length; j++)
{
if (i == j)
{
arr[i, j] = 1;
}
else
{
var curr = rnd.Next(0, 2);
arr[i, j] = curr;
var reverse = curr switch
{
0 => 2,
1 => 1,
2 => 0,
_ => throw new Exception("Should not happen")
};
// or if C# 8.0 is not way to go:
//int reverse;
//switch (curr)
//{
// case 0: reverse = 2; break;
// case 1: reverse = 1; break;
// case 2: reverse = 0; break;
// default: throw new Exception("Should not happen");
//}
arr[j, i] = reverse;
}
}
}

Displaying an arrays index number

I need help with C#
I'm currently trying to find the minimum value in a 2D array. I have managed to do this however, after I have found the minimum value I want the corresponding values index number (Where it is stored in my 2D array) to be output. For example, I have a 2D and a 1D array. Once the minimum value has been discovered the index value for the 2D array needs to be changed in the 1D array.
The 2d array is c[i,j]
and the 1D array is a[i]
so how would i be able to display the j number in my c array in my a array. For example, if my minimum value was at c[1,5] I want the value in a[5] to be changed from 0 to 1. Any help would be great thanks!
P.S. if ive made this sound really confusing I apologise I'm new to this !
int n = 5, m = 10, MinValue = 100, MaxValue = 1, Total = 0, Sum = 0; //n = number of values m = max value in array MinValue = Lowest number in array
Random Rand = new Random();
int[] A = new int[n + 1];
for (int i = 1; i < n+1; i++) //Reached and unreached array - creation
{
A[i] = 0;
}
A[1] = 1;
int[,] c = new int[n + 1, n + 1]; //Create array
for (int i = 1; i <= n; i++)
{
for (int j = 1; j <= n; j++)
{
c[i, j] = Rand.Next(1, m); //Randomise the array
if (i == j)
{
c[i, j] = 99; // give void spaces the value of 99
}
if (c[i, j] > MaxValue && c[i, j] < 99)
{
MaxValue = c[i, j]; // max value takes the highest value (that isnt 99)
}
}
}
for (int p = 1; p <= n; p++)
{
for (int i = 1; i <= n+1; i++)
{
for (int j = 1; i <= n+1; i++)
{
if (c[i, j] <= MinValue)
{
if (A[i] == 1)
{
if (A[i] == 0)
{
Total = Sum + MinValue;
Sum = Total;
A[i] = 1;
}
}
}
}
}
}
Console.WriteLine("Total Value = " + Total);
Console.WriteLine("");
Console.WriteLine("The tracking array - what has been reached and what hasn't"); // Output reaching array
Console.WriteLine("");
for (int i = 1; i <= n; i++)
{
Console.WriteLine("A[" + i + "] = " + A[i].ToString("00") + " ");
//Output the array to screen
}
Console.WriteLine("");
Console.WriteLine("The link length array"); // Output link length array
Console.WriteLine("");
for (int i = 1; i <= n; i++)
{
for (int j = 1; j <= n; j++)
{
Console.Write("c[" + i + "," + j + "] = " + c[i, j].ToString("00") + " ");
}
Console.WriteLine();
//Output the array to screen
}
Console.WriteLine("");
Console.ReadLine();

How to get all possible 2x2 sub matrices in a 3x3 matrix in C#?

If matrix A of size (3x3), then should i use the method of finding determinants, like grabbing the rows and column of first element and removing it from the array 2D array to get the remaining elements and then moving to the next element and repeating the same steps ?
[{1,2,3},
{4,5,6},
{7,8,9}]

I finally was able to do it, here's what I did :
enter image description here
class program
{
public static void Main()
{
int[,] arr = new int[3, 3];
Console.WriteLine("Enter elements of " + (arr.GetUpperBound(0) + 1) + "x" + (arr.GetUpperBound(1) + 1) + " matrix:");
for (int i = 0; i < (arr.GetUpperBound(0) + 1); i++)
{
for (int j = 0; j < (arr.GetUpperBound(1) + 1); j++)
{
arr[i, j] = Convert.ToInt32(Console.ReadLine());
}
}
Console.WriteLine("Matrix entered: ");
for (int i = 0; i < (arr.GetUpperBound(0) + 1); i++)
{
for (int j = 0; j < (arr.GetUpperBound(1) + 1); j++)
{
Console.Write("\t" + arr[i, j]);
}
Console.WriteLine();
}
Console.WriteLine("Possible sub-matrices: ");
for (int i = 0; i < 3; i++)
{
for (int j = 0; j< 3; j++)
{
TrimArray(i,j,arr);
}
}
}
public static int[,] TrimArray(int row, int column, int[,] original)
{
int[,] resultant = new int[original.GetLength(0) - 1, original.GetLength(1) - 1];
for (int i = 0, j = 0; i < original.GetLength(0); i++)
{
if (i == row)
continue;
for (int k = 0, u = 0; k < original.GetLength(1); k++)
{
if (k == column)
continue;
resultant[j, u] = original[i, k];
u++;
}
j++;
}
Console.WriteLine();
for (int i = 0; i < 2; i++)
{
for (int j = 0; j< 2; j++)
{
Console.Write("\t"+resultant[i,j]);
}
Console.WriteLine();
}
return resultant;
}
}

I did this for you yesterday, I created a method that will return a square matrix, given a parent matrix and the length.
static void Main(string[] args)
{
int[][] parentMatrix = new int[][]
{
new int [] { 1, 2, 3 },
new int [] { 4, 5, 6 },
new int [] { 7, 8, 9 }
};
var chunks = GetSubMatrices(parentMatrix, 2);
Console.WriteLine(chunks);
}
static List<int[][]> GetSubMatrices(int[][] parentMatrix, int m)
{
int n = parentMatrix.Length > m ? parentMatrix.Length : throw new InvalidOperationException("You can't use a matrix smaller than the chunk size");
var chunks = new List<int[][]>();
int movLimit = n - m + 1;
var allCount = Math.Pow(movLimit, 2);
for (int selRow = 0; selRow < movLimit; selRow ++)
{
for (int selCol = 0; selCol < movLimit; selCol ++)
{
// this is start position of the chunk
var chunk = new int[m][];
for (int row = 0; row < m; row++)
{
chunk[row] = new int[m];
for (int col = 0; col < m; col++)
{
chunk[row][col] = parentMatrix[selRow + row][selCol + col];
}
}
chunks.Add(chunk);
}
}
return chunks;
}
If you have any problems using it, you can simply comment below.

I needed to solve a problem like and came up with this answer. Hope it adds to your library of answers. If the submatrix specified is not greater than 1, do nothing.
public static void GetSubMatrixes(int[,] arr, int size)
{
int parentMatrixRowLength = arr.GetLength(0);
int parentMatrixColLength = arr.GetLength(1);
var overall = new List<object>();
if(size > 1)
{
for (int i = 0; i < parentMatrixRowLength; i++)
{
//get the columns
for (int j = 0; j < parentMatrixColLength; j++)
{
var subMatrix = new int[size, size];
/*if the new matrix starts from second to the last value in either the row(horizontal or column)
* do not proceed, go to the row or column in the parent matrix
* */
if (j < parentMatrixColLength - (size - 1) && i < parentMatrixRowLength - (size - 1))
{
//add
for (int m = 0; m < subMatrix.GetLength(0); m++)
{
for (int n = 0; n < subMatrix.GetLength(1); n++)
{
/*check the sum of current column value and the sum of the current row value
* of the parent column length and row length if it goes out of bounds
*/
var row = i + m; var col = j + n;
//actual check here
if (row < parentMatrixRowLength && col < parentMatrixColLength)
{
subMatrix[m, n] = arr[i + m, j + n];
}
}
}
overall.Add(subMatrix);
}
}
}
//display the sub matrixes here
for (int i = 0; i < overall.Count; i++)
{
var matrix = overall[i] as int[,];
for (int y = 0; y < matrix.GetLength(0); y++)
{
for (int x = 0; x < matrix.GetLength(1); x++)
{
Console.Write(string.Format("{0} ", matrix[y, x]));
}
Console.Write(Environment.NewLine + Environment.NewLine);
}
Console.WriteLine();
}
}
}