Index Out Of Range Bucket Sort - c#

So I wrote bucket sort implementation (I use rnd.NextDouble() to fill my array, so all the elements are in the range between 0 and 1). And I have number of experiments (10 experiments for each array size) and different array sizes (I start with 1000 and then +1000, etc. till 300.000). And sometimes it works fine, but sometimes it gives me OutOfRange exception:
public static void BucketSortImplement(ref int countOfElements, ref float[] array)
{
List<float>[] buckets = new List<float>[countOfElements];
for (int i = 0; i < countOfElements; i++)
{
buckets[i] = new List<float>();
}
for (int i = 0; i < countOfElements; i++)
{
float indexOfElement = array[i] * countOfElements;
buckets[(int)indexOfElement].Add(array[i]); // right here
}
for (int i = 0; i < countOfElements; i++)
{
for (int j = 0; j < buckets[i].Count; j++)
{
float keyElement = buckets[i][j];
int k = j - 1;
while (k >= 0 && buckets[i][k] > keyElement)
{
buckets[i][k + 1] = buckets[i][k];
k -= 1;
}
buckets[i][k + 1] = keyElement;
}
}
int arrayIndex = 0;
for (int i = 0; i < countOfElements; i++)
{
for (int j = 0; j < buckets[i].Count; j++)
{
array[arrayIndex++] = buckets[i][j];
}
}
}
I am a bit confused, because the algorithm itself looks fine, that is I have to calculate array[i] * countOfElements to get the index where I can put my element. Could you please direct me?

If you array contain value '1' it will lead to OutOfRange, because if you have a size of the list equal to 3 (for example) then valid indexes will be in the range [0, 2].

Related

Index out of range for multi dimensional array

I'm getting the error that the index for my array is out of range.
I define a 3D array like this:
Button[, ,] posAr_ItemManager = new Button[maxRows, maxColumns, maxCategories];
Where maxRows, maxColumns and maxCategories are all constant integers.
I then want to loop through this whole array, i do it using nested loops as shown here:
for (int i = 0; i < posAr_ItemManager.GetLength(0); i++)
{
for (int j = 0; i < posAr_ItemManager.GetLength(1); j++)
{
for (int z = 0; i < posAr_ItemManager.GetLength(2); z++)
{
if (posAr_ItemManager[i,j,z] != null)
{
Button but = posAr_ItemManager[i, j, z];
but.Width = itemWidth;
but.Height = itemHeight;
but.SetValue(Canvas.LeftProperty, itemPanelX + (i + 1) * butSpacing + i * itemWidth);
but.SetValue(Canvas.TopProperty, itemPanelY + (i+1)*butSpacing + i* itemHeight);
}
}
}
}
When I run the program it gives the out of range error where I check if the item is not equal to null.
I have no idea why it does it as I thought my declaration of the 3D array is correct and the nested loop as well? thanks in advance!
for (int i = 0; i < posAr_ItemManager.GetLength(0); i++)
{
for (int j = 0; j < posAr_ItemManager.GetLength(1); j++)
{
for (int z = 0; z < posAr_ItemManager.GetLength(2); z++)
look very carefully at the middle tests. Also, consider hoisting the GetLength tests so you only do them once per dimension. Perhaps:
int rows = posAr_ItemManager.GetLength(0), columns = posAr_ItemManager.GetLength(1),
categories = posAr_ItemManager.GetLength(2);
for (int row = 0; row < rows; row++)
{
for (int col = 0; col < columns; col++)
{
for (int cat = 0; cat < categories; cat++)
You're using "i" to check if the loop is over in each of the dimensions. Change it to corresponded i,j,z.
for (int i = 0; i < posAr_ItemManager.GetLength(0); i++)
{
for (int j = 0; **j** < posAr_ItemManager.GetLength(1); j++)
{
for (int z = 0; **z** < posAr_ItemManager.GetLength(2); z++)

How to fix this implementaion of the Merge Sort in c#

I've read the CLRS and tried to implement the recursive merge sort algorithm . cant see what the error is but everytime i run it gives me an "Index out of bounds error "
i've been trying for 5h now
static public void MergeSort(int[] input, int IndexStanga, int IndexDreapta)
{
if (IndexStanga < IndexDreapta)
{
int IndexMijloc = (IndexDreapta + IndexStanga) / 2;
MergeSort(input, IndexStanga, IndexMijloc);
MergeSort(input, IndexMijloc + 1, IndexDreapta);
Merge(input, IndexStanga, IndexDreapta, IndexMijloc);
}
}
static public void Merge(int[] input, int stanga, int dreapta, int mijloc)
{
int lungDR = 0;
int lunST = 0;
lungDR = dreapta - mijloc;
lunST = mijloc - stanga + 1;
int[] valDreapta = new int[lungDR + 1];
int[] valStanga = new int[lunST + 1];
valDreapta[valDreapta.Length - 1] = int.MaxValue;
valStanga[valStanga.Length - 1] = int.MaxValue;
int i = 0;
int j = 0;
for (i = stanga; i <= mijloc; i++) valStanga[i] = input[i];
for (i = 0; i < lungDR; i++) { valDreapta[i] = input[i + mijloc + 1]; }
i = 0;
j = 0;
for (int k = 0; k < input.Length; k++)
{
if (valStanga[i] <= valDreapta[j]) //error out of bounds
{
input[k] = valStanga[i];
i++;
}
else
{
input[k] = valDreapta[j];
j++;
}
}
}
Fixes noted in comments below. First fix for moving data from input to valStanga. Second fix for the range on merging back to input. The parameters for merge are in an unusual order, first, last, middle. Normally the order is first, middle, last.
Comments: The program will have issues if the array to be sorted contains elements equal to max integer. It would be more efficient to do a one time allocation of a working array, rather than allocate new sub-arrays on every call to merge. The copy operations can be avoided by changing the direction of merge with each level of recursion.
int i = 0;
int j = 0;
for (i = 0; i < lungDR; i++) { valDreapta[i] = input[i + mijloc + 1]; }
for (i = 0; i < lunST; i++) { valStanga[i] = input[i + stanga]; } // fix
i = 0;
j = 0;
for (int k = stanga; k <= dreapta; k++) // fix
{
if (valStanga[i] <= valDreapta[j])

Is there a way to increase the stack size in c#?

I'm coming back to programming after having done none for several years, and created a Sudoku game to get my feet wet again. I've written a recursive function to brute-force a solution, and it will do so for simple board states, but runs into a stack overflow most of the time for more complicated board states. I know that this could be averted using loops or a more efficient algorithm, but since this is for the sake of learning I want to know how to allocate more memory to the stack (acknowledging this isn't the best solution to the problem).
An answer here: How to change stack size for a .NET program? that recommends using a thread with more memory allocated isn't working, as from what I can read .NET 4.0 will not let you increase a thread's maximum allocated memory beyond the default.
Another solution recommends using EDITBIN.EXE, but I am new to Visual Studio and have not found an explanation I understand of how to do so.
Similarly, I've found that you can use a .def file to indicate a larger default stack size, but have not found an explanation I understand of how to create/implement one.
Can anyone offer newbie-level explanations of either EDITBIN.EXE or .def file implementations, or offer another way to increase the stack size?
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
namespace Sudoku
{
//object keeps track of the value of all numbers currently on the board using an array
class BoardState
{
int testcount = 1;
//3d array of ints representing all values on the board, represted as region, column, row
int[,,] boardVals;
//3d array of bools representing if a number is immutable (true cannot be changed, false can be)
bool[,,] fixedVals;
//create a blank board if no initial values are provided
public BoardState()
{
boardVals = new int[9, 3, 3];
fixedVals = new bool[9, 3, 3];
}
//create a board with the listed initial values as immutable
public BoardState(int[,,] inputVals)
{
boardVals = inputVals;
fixedVals = new bool[9,3,3];
for (int i = 0; i < 9; ++i)
for (int j = 0; j < 3; ++j)
for (int k = 0; k < 3; ++k)
if (boardVals[i, j, k] > 0) fixedVals[i, j, k] = true;
}
//update the state of the board using the coordinates of a single value
//**note** method has not been implemented and tested yet
public void updateState(int region, int column, int row, int val)
{
if (!fixedVals[region, column, row])
{
boardVals[region, column, row] = val;
}
}
//update the state of the board to match the state of another board
public void updateState(int[,,] newState)
{
boardVals = newState;
}
public int[,,] getVals()
{
return boardVals;
}
public bool[,,] getFixed()
{
return fixedVals;
}
//set all non-zero values to be immutable
public void setFixed()
{
for (int i = 0; i < 9; i++)
for (int j = 0; j < 3; j++)
for (int k = 0; k < 3; k++) {
if (boardVals[i, j, k] != 0)
fixedVals[i, j, k] = true;
else
fixedVals[i, j, k] = false;
}
}
//test method
public void testState()
{
for (int i = 0; i < 9; i++)
for (int j = 0; j < 3; j++)
for (int k = 0; k < 3; k++)
Console.WriteLine(boardVals[i, k, j]);
}
//accepts a 3d array representing the current board state.
//returns a 3d bool array denoting whether any region, row, or column is invalid (true=invalid)
//first value of array designates the region, row, or column respectively
//second value designates which of those is invalid
public bool[,] validateBoard()
{
bool[,] valid = new bool[3, 9];
int[,] rows = makeRows(boardVals);
int[,] cols = makeCols(boardVals);
//compare each value in each row to each other value in that row
for (int i = 0; i < 9; i++)
{
for (int j = 0; j < 9; j++)
{
//only validate an entry if it has been assigned a value
if (rows[i, j] != 0)
{
for (int k = 0; k < 9; k++)
{
//if two values are not the same entry and are equal, set that entry to invalid
if (j != k && rows[i, j] == rows[i, k])
valid[1, i] = true;
}
}
}
}
//compare each value in each column to each other value in that column
for (int i = 0; i < 9; i++)
{
for (int j = 0; j < 9; j++)
{
//only validate an entry if it has been assigned a value
if (cols[i, j] != 0)
{
for (int k = 0; k < 9; k++)
{
//if two values are not the same entry and are equal, set that entry to invalid
if (j != k && cols[i, j] == cols[i, k])
valid[2, i] = true;
}
}
}
}
//compare each value in each region to each other value in that region
for (int i = 0; i < 9; i++)
{
for (int j = 0; j < 3; j++)
{
for (int k = 0; k < 3; k++)
{
//only validate an entry if it has been assigned a value
if (boardVals[i, j, k] != 0)
{
for (int l = 0; l < 3; l++)
{
for (int m = 0; m < 3; m++)
{
//if two values are not the same entry and are equal, set that entry to invalid
if (!(l == j && m == k) && boardVals[i, j, k] == boardVals[i, l, m])
valid[0, i] = true;
}
}
}
}
}
}
return valid;
}
public bool isValid()
{
bool retFlag = true;
bool[,] valid = new bool[3, 9];
int[,] rows = makeRows(boardVals);
int[,] cols = makeCols(boardVals);
//for (int i = 0; i < 9; i++)
// for (int j = 0; j < 3; j++)
// for (int k = 0; k < 3; k++)
// Console.Write(boardVals[i, j, k]);
//compare each value in each row to each other value in that row
for (int i = 0; i < 9; i++)
{
for (int j = 0; j < 9; j++)
{
//only validate an entry if it has been assigned a value
if (rows[i, j] != 0)
{
for (int k = 0; k < 9; k++)
{
//if two values are not the same entry and are equal, set that entry to invalid
if (j != k && rows[i, j] == rows[i, k])
{
retFlag = false;
}
}
}
}
}
//compare each value in each column to each other value in that column
for (int i = 0; i < 9; i++)
{
for (int j = 0; j < 9; j++)
{
//only validate an entry if it has been assigned a value
if (cols[i, j] != 0)
{
for (int k = 0; k < 9; k++)
{
//if two values are not the same entry and are equal, set that entry to invalid
if (j != k && cols[i, j] == cols[i, k])
{
retFlag = false;
}
}
}
}
}
//compare each value in each region to each other value in that region
for (int i = 0; i < 9; i++)
{
for (int j = 0; j < 3; j++)
{
for (int k = 0; k < 3; k++)
{
//only validate an entry if it has been assigned a value
if (boardVals[i, j, k] != 0)
{
for (int l = 0; l < 3; l++)
{
for (int m = 0; m < 3; m++)
{
//if two values are not the same entry and are equal, set that entry to invalid
if (!(l == j && m == k) && boardVals[i, j, k] == boardVals[i, l, m])
{
retFlag = false;
}
}
}
}
}
}
}
return retFlag;
}
//returns an array of all the values in each row
public int[,] makeRows(int[,,] boardState)
{
int[,] rows = new int[9, 9];
for (int i = 0; i < 9; i++)
for (int j = 0; j < 9; j++)
rows[i, j] = boardState[j / 3 + ((i / 3) * 3), j % 3, i - ((i / 3) * 3)];
return rows;
}
//returns an array of all values in each column
public int[,] makeCols(int[,,] boardState)
{
int[,] cols = new int[9, 9];
for (int i = 0; i < 9; i++)
for (int j = 0; j < 9; j++)
cols[i, j] = boardState[((j / 3) * 3) + (i / 3), i - ((i / 3) * 3), j % 3];
return cols;
}
//update the board state to a state read in from a file
public void updateFromFile(Stream update)
{
int[,,] newVals = new int[9, 3, 3];
int[,,] newFixed = new int[9, 3, 3];
StreamReader file = new StreamReader(update);
for (int i = 0; i < 9; i++){
for (int j = 0; j < 3; j++){
for (int k = 0; k < 3; k++){
boardVals[i, j, k] = (int)char.GetNumericValue((char)file.Read());
}
}
}
for (int i = 0; i < 9; i++){
for (int j = 0; j < 3; j++){
for (int k = 0; k < 3; k++){
fixedVals[i, j, k] = (0 != ((int)char.GetNumericValue((char)file.Read())));
}
}
}
file.Close();
}
public void Solve(int entry, int val)
{
Console.WriteLine("This is call number " + ++testcount);
//returns if all values are filled and valid
if (entry == 81)
{
Console.WriteLine("Solved!");
return;
}
//creating reference coordinates based on entry value
int reg = entry / 9;
int col = (entry - (reg * 9)) % 3;
int row = (entry - (reg * 9)) / 3;
//if current entry being checked is a fixed value, go the next value
if (!fixedVals[reg, row, col])
{
Console.WriteLine("");
Console.WriteLine("Making an attempt at entry " + entry + " using value " + val);
Console.WriteLine("This entry is at region " + reg + ", col " + col + ", row " + row);
//assign entry the value to be tested
boardVals[reg, row, col] = val;
//if the value is valid, go to the next entry
if (isValid())
{
Console.WriteLine("Entry Valid at " + entry);
val = 1;
entry++;
Console.WriteLine("Trying the next entry at " + entry);
Solve(entry, val);
}
//if the value is invlid and all 9 values have not been tried,
//increment value and call again at same entry
if (!isValid() && val < 9)
{
Console.WriteLine("Entry Invalid at " + entry + " with value " + val);
++val;
Console.WriteLine("Trying again with value " + val);
Solve(entry, val);
}
//if the value in invalid and all 9 values have been tried,
//zero out the entry and go back to the previous non-fixed entry
if (!isValid() && val == 9)
{
do
{
boardVals[reg, row, col] = 0;
Console.WriteLine("Reached Value 9 and was still invalid");
--entry;
Console.WriteLine("Trying again at entry " + entry);
Console.WriteLine("The value at that entry is " + boardVals[reg, row, col]);
reg = entry / 9;
col = (entry - reg * 9) % 3;
row = (entry - reg * 9) / 3;
if (fixedVals[reg, row, col])
Console.WriteLine("But that's a fixed value, so I'll go back one more");
Console.WriteLine("");
} while (boardVals[reg, row, col] == 9 || fixedVals[reg, row, col]);
val = boardVals[reg, row, col] + 1;
Solve(entry, val);
}
}
else Solve(++entry, val);
}
}
}
The big bad warning
If you use recursion in a program and reach a point where having a StackOverflowException is an actual threat, please do not consider increasing the stack size as a valid solution.
If you encounter a StackOverflowException you are doing something very wrong; you should instead be using a Stack<T> for depth-first processing, or a Queue<T> for breadth-first processing. Example.
The solution
This can be achieved by using editbin.exe, which is installed with this package;
Find the location of editbin.exe, mine was located at C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.14.26428\bin\Hostx64\x64\editbin.exe, I would suggest using Everything by voidtools in lieu of Microsoft's awful search to find this.
Set the stack size manually
Navigate to your bin folder and execute the following:
"<full path of editbin.exe>" /stack:<stack size in bytes, decimal> <your executable name>
For example I executed this:
"C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.14.26428\bin\Hostx64\x64\EDITBIN.EXE" /stack:2097152 ExampleProgram.exe
Which set the stack reserve size to 2MB.
With this I was capable of reaching twice the recursion level; (1MB stack reserve on left, 2MB stack reserve on right).
Set the stack size automatically
Right click on your project and select 'Options', then click on 'Build Events' and add the following to your post-build events:
"<full path of editbin.exe>" /stack:<stack size in bytes, decimal> "$(TargetPath)"
For example I added
"C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.14.26428\bin\Hostx64\x64\EDITBIN.EXE" /stack:2097152 "$(TargetPath)"
This will run editbin.exe every time you build your executable.
Note: You will see a lot lower level of recursion reached when running your program from Visual Studio as you will from running it explicitly via explorer or cmd. You will still however see a 2x increase in the level of recursion met if moving from a 1MB stack reserve to a 2MB stack reserve.
Perhaps set the Stack Reserve Size in Visual Studio:
Project -> Properties -> Configuration Properties -> Linker -> System -> Stack Reserve Size
This can also be done via the command-line or programatically when a thread is created:
https://learn.microsoft.com/en-us/cpp/build/reference/stack-stack-allocations?view=vs-2017

Chess board positions

How can i make this so the user types positions in console (table[4,5]) i want that user types that?
int[,] table = new int[8, 8];
for (int i = 0; i < 8; i++)
{
for (int j = 0; j < 8; j++)
{
if ((i + j) % 2 == 0)
{
table[i, j] = 0;
}
else
{
table[i, j] = 1;
}
}
}
Console.WriteLine("4 - king");
Console.WriteLine("3 - queen");
Console.WriteLine("4 - hunter");
table[4,5] = 2;
table[6,7] = 3;
table[2,2] = 4;
for (int i = 0; i < 8; i++)
{
for (int j = 0; j < 8; j++)
{
Console.Write(table[i, j] + " ");
}
Console.WriteLine();
}
What should i do to make this work?And if i type this it doesnt work:
Thats why i have to put figures in different rows or columns how do i fix this
table[4,5] = 2;
table[4,7] = 3;
table[2,2] = 4;
You are confusing the assignment operator "=" with the logical comparison operator "==". Your second line is just comparing table[4,5] with 2 and probably returning false.
Change it to:
table[4,5] = 2;
Also, even if you manage to assign a value to table[4,5], you will overwrite it in the next lines. You should move that line to the end of the first nested loop. Just before the second "for (int i = 0; i < 8; i++)"

C# program that returns morse code for numbers not working

I'm trying to make a program that: When given a 4 digit number (for example, 1001) it sums the digits of that number, for 1001 this is 1 + 0 + 0 + 1 = 2, than it finds all sequences of 6 numbers from 1 to 6 (including permutations, i.e. 1*1*1*1*1*2 is different than 2*1*1*1*1*1) whose product is that number.
The result should be printed on the console in the following format: each sequence of 6 numbers, with their Morse representation, separated with a single pipe: 1 is .---- , 2 is ..---: .----|.----|.----|.----|..---|, on a new row the next permutation: .----|.----|.----|..---|.----| and so on.
The problem is, my solution doesn't show the correct answers, not even the correct number of them.
Here's my code (and please, if possible, tell me where my mistake is, and not some one line hack solutions to the problem with LINQ and regex and God knows what):
string n = Console.ReadLine();
string[] digitsChar = new string[n.Length];
for (int i = 0; i < 4; i++)
{
digitsChar[i] = n[i].ToString();
}
int[] digits = new int[digitsChar.Length];
for (int i = 0; i < 4; i++)
{
digits[i] = Convert.ToInt32(digitsChar[i]);
}
int morseProduct = digits.Sum();
Console.WriteLine(morseProduct);
List<int> morseCodeNumbers = new List<int>();
for (int i = 1; i < 6; i++)
{
for (int j = 1; i < 6; i++)
{
for (int k = 1; i < 6; i++)
{
for (int l = 1; i < 6; i++)
{
for (int m = 1; i < 6; i++)
{
for (int o = 1; o < 6; o++)
{
int product = i * j * k * l * m * o;
if (product == morseProduct)
{
morseCodeNumbers.Add(i);
morseCodeNumbers.Add(j);
morseCodeNumbers.Add(k);
morseCodeNumbers.Add(l);
morseCodeNumbers.Add(m);
morseCodeNumbers.Add(o);
}
}
}
}
}
}
}
int numberOfNumbers = morseCodeNumbers.Count;
string[] morseCodes = new string[] { "-----", ".----", "..---", "...--", "....-", "....." };
for (int i = 0; i < numberOfNumbers; i++)
{
int counter = 0;
if (i % 5 == 0)
{
Console.WriteLine();
counter = 0;
}
if (counter < 5)
{
int index = morseCodeNumbers[i];
Console.Write(morseCodes[index] + "|");
counter++;
}
A lot of your for-loop conditions refer to i instead of j,k,l and m. The same for the increment part. For example:
for (int j = 1; i < 6; i++)
should be
for (int j = 1; j < 6; j++)
Furthermore if the range is from 1 to 6 you need to change < to <=, see:
for (int i = 1; i <= 6; i++)
You don't need to convert the string to a string array to get the int array of digits btw, so while this is correct:
for (int i = 0; i < 4; i++)
{
digitsChar[i] = n[i].ToString();
}
int[] digits = new int[digitsChar.Length];
for (int i = 0; i < 4; i++)
{
digits[i] = Convert.ToInt32(digitsChar[i]);
}
you could it do like that (sry for LINQ):
var digits = n.Select(c=>(int)char.GetNumericValue(c) ).ToArray();

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