I am just sorting an array and my code seem to be fine but I am unable to resolve the Array Out of Bound Exception. Any ideas.
static void Main(string[] args)
{
int temp = 0; // For temporary holding array values for swapping
int [] num = new int[] {1, 4, 7, 6, 9, 3, 0, 8, 5, 2 };
for (int i = 0; i <= 9; i++) //Outer loop
{
for (int j = 0; j < 9; j++) // Inner loop
{
if (num[j] > num[j + 1])
{
temp = num[j + 1];
num[j + 1] = num[j];
num[j] = temp;
}
}
}
//Displaying the array
for (int i = 0; i < 9; i++)
Console.WriteLine(num[i]);
Console.ReadKey();
}
Modifying the second loop to "j < loopSize - i" (instead of j < loopSize) will double the efficiency of your bubble sort. :)
int[] num = new int[] { 1, 4, 7, 6, 9, 3, 0, 8, 5, 2 };
//int comparisons = 0;
int loopSize = num.Length - 1;
for (int i = 0; i <= loopSize; i++) //Outer loop
{
for (int j = 0; j < loopSize - i; j++) // Inner loop
{
//comparisons++;
if (num[j] > num[j + 1])
{
temp = num[j + 1];
num[j + 1] = num[j];
num[j] = temp;
}
}
}
//Displaying the array
for (int i = 0; i < num.Length; i++)
Console.WriteLine(num[i]);
//Console.WriteLine("comp: {0}", comparisons);
//Console.ReadKey();
}
Related
So, I needed to find all the index of elements from an array whose sum is equal to N.
For example : Here I want to find indexes whose sum should be equal to 10.
Input : int[] arr = { 2, 3, 0, 5, 7 }
Output: 0,1,3
If you add indexes arr[0] + arr[1] + arr[3] then 2 + 3 + 5 = 10.
I have tried this, but I am running 3 for loops and 3 if conditions, Can we write this in less code, I want to reduce code complexity.
PS: Post suggestions, not codes..
public static void Check1()
{
int[] arr = { 2, 3, 0, 5, 7 };
int target = 10; int total = 0;
bool found = false;
List<int> lst = new List<int>();
for (int i = 0; i < arr.Length; i++)
{
if (!found)
{
for (int j = i + 1; j < arr.Length; j++)
{
if (!found)
{
total = arr[j] + arr[i];
for (int k = j + 1; k < arr.Length; k++)
{
if (total + arr[k] == target)
{
found = true;
Console.WriteLine($"{i}, {i + 1}, {k}");
break;
}
}
}
}
}
}
Console.ReadLine();
}
I am learning C#, and I am doing Multidimensional Arrays at the moment. I want to write a program that reads a matrix and then finds the biggest sum of 2x2 submatrix and prints it.
int[] dimensions = Console.ReadLine()
.Split(", ", StringSplitOptions.RemoveEmptyEntries)
.Select(int.Parse)
.ToArray();
int rows = dimensions[0];
int columns = dimensions[1];
int[,] matrix = new int[rows,columns];
for (int i = 0; i < rows; i++)
{
int[] numbers = Console.ReadLine()
.Split(", ", StringSplitOptions.RemoveEmptyEntries)
.Select(int.Parse)
.ToArray();
for (int j = 0; j < columns; j++)
{
matrix[i, j] = numbers[j];
}
}
int maxSum = int.MinValue;
int selectedRow = -1;
int selectedCol = -1;
for (int row = 0; row < matrix.GetLength(0) - 1; row++)
{
for (int col = 0; col < matrix.GetLength(1) - 1; col++)
{
int currentSum = matrix[row, col] + matrix[row, col + 1] + matrix[row + 1, col] + matrix[row + 1, col + 1];
if (currentSum > maxSum)
{
maxSum = currentSum;
selectedRow = row;
selectedCol = col;
}
}
}
Console.WriteLine($"{matrix[selectedRow, selectedCol]} {matrix[selectedRow, selectedCol + 1]}");
Console.WriteLine($"{matrix[selectedRow + 1, selectedCol]} {matrix[selectedRow + 1, selectedCol + 1]}");
Console.WriteLine(maxSum);
So, I read the matrix, but I am not sure how to start finding the submatrices and compare their sums. I would be very grateful if you could give me some hints.
You need to check values only current, under positions of your i and current, right positions of your j.
I mean it will check like this:
[7,1] [1,3] [3,3]
[1,3] [3,9] [9,8]
And so on.
After every compare, calculate sum of this 2x2 matrix and save it to dictionary.
For return, you just need to find the max value of key and get value of it key.
public class MatrixTest
{
public static IEnumerable<object[]> TestData =>
new List<object[]>
{
new object[]
{
new int[,]
{
{7, 1, 3, 3, 2, 1},
{1, 3, 9, 8, 5, 6},
{4, 6, 7, 9, 1, 0}
},
new int[,]
{
{9, 8},
{7, 9}
},
33
},
new object[]
{
new int[,]
{
{10, 11, 12, 13},
{14, 15, 16, 17}
},
new int[,]
{
{12, 13},
{16, 17}
},
58
}
};
[Theory]
[MemberData(nameof(TestData))]
public void Test(int[,] input, int[,] expectedArray, int expectedSum)
{
MatrixHandler m = new MatrixHandler();
var resp = m.GetMax2x2Matrix(input);
resp.Item1.Should().Be(expectedSum);
resp.Item2.Should().BeEquivalentTo(expectedArray);
}
}
public class MatrixHandler
{
public (int, int[,]) GetMax2x2Matrix(int[,] source)
{
var sumsPlusTempArrays = new Dictionary<int, int[,]>();
int[,] temp;
int sum = 0;
for (int i = 0, n0 = source.GetLength(0) - 1; i <= n0; i++)
{
for (int j = 0, n1 = source.GetLength(1) - 1; j <= n1; j++)
{
if (i + 1 <= n0 && j + 1 <= n1)
{
temp = new int[2,2];
temp[0, 0] = source[i, j];
temp[0, 1] = source[i, j + 1];
temp[1, 0] = source[i + 1, j];
temp[1, 1] = source[i + 1, j + 1];
sum = CalculateSum(temp);
sumsPlusTempArrays.TryAdd(sum, temp);
}
}
}
var key = sumsPlusTempArrays.Select(x => x.Key).Max();
var value = sumsPlusTempArrays[key];
return (key, value);
}
private int CalculateSum(int[,] source)
{
int sum = 0;
for (int i = 0, n0 = source.GetLength(0); i < n0; i++)
{
for (int j = 0, n1 = source.GetLength(1); j < n1; j++)
{
sum += source[i, j];
}
}
return sum;
}
}
The prompt is to find the maximal sequence of consecutive equal elements in an array. I don't know what I'm doing wrong but I can't get the right result to show up. :/ Maybe the problem is in the way I iterate with the second loop?
class Class2
{
static void Main(string[] args)
{
int pos=0, bestpos=0, bestlen = 0;
int len = 1;
int[] vargu = { 2, 2, 3, 4, 5, 5, 5, 6, 9, 9, 9, 9 };
for(int i = 0; i < vargu.Length-1; i++)
{
if (vargu[i] == vargu[i++])
{
len++;
if (len > bestlen)
{
bestlen = len;
bestpos = pos;
}
}
else
{
len = 1;
pos = i++;
}
}
for(int k = bestpos; k <= bestlen; k++)
{
Console.Write("{0}", vargu[k]);
}
Console.ReadLine();
}
}
3 problems.
if (vargu[i] == vargu[i++])
dont use ++ with i, it means increment the actual value of i, and you are looping i. Use "i+1" instead.
pos = i++;
same problem here. the array wont get traversed by each index due to this line.
for(int k = bestpos; k <= bestlen; k++)
k < bestlen + bestpos, because bestpos = 8, and bestlen = 4, so loop run condition fails.
int pos = 0, bestpos = 0, bestlen = 0;
int len = 1;
int[] vargu = { 2, 2, 3, 4, 5, 5, 5, 6, 9, 9, 9, 9 };
for (int i = 0; i < vargu.Length - 1; i++)
{
if (vargu[i] == vargu[i+1])
{
len++;
if (len > bestlen)
{
bestlen = len;
bestpos = pos;
}
}
else
{
len = 1;
pos = i+1;
}
}
for (int k = bestpos; k < bestlen + bestpos; k++)
{
Console.Write("{0} ", vargu[k]);
}
Console.ReadLine();
You're using i++ in the loop body when you mean i + 1.
Note that i++ has the side effect of increasing i by 1. Leave the incrementation of i solely in for (int i = 0; i < vargu.Length - 1; i++).
Your problem is 2-fold.
First i++ increments the variable i which shifts the index forward. Something that you don't want. You need to use i+1 if you want to access the consecutive element
Second, when you print in the second loop your array the end-index is wrong. You start at bestpos but you want to end at bestpos + bestlen! Since you measure the length of the sequence and don't save the final index.
This should give you the expected result:
int pos = 0, bestpos = 0, bestlen = 0;
int len = 1;
int[] vargu = { 2, 2, 3, 4, 5, 5, 5, 6, 9, 9, 9, 9 };
for (int i = 0; i < vargu.Length - 1; i++)
{
if (vargu[i] == vargu[i+1])
{
len++;
if (len > bestlen)
{
bestlen = len;
bestpos = pos;
}
}
else
{
len = 1;
pos = i+1;
}
}
for (int k = bestpos; k <= bestpos+bestlen; k++)
{
Console.Write("{0}", vargu[k]);
}
Console.ReadLine();
I would suggest making a structure to hold results :
struct ResultItem
{
public int start;
public int end;
public int value;
}
And then just iterate and compare when signs are changing :
int[] vargu = { 2, 2, 3, 4, 5, 5, 5, 6, 9, 9, 9, 9 };
List<ResultItem> _result = new List<ResultItem>();
ResultItem current = new ResultItem{ value = vargu[0], start = 0, end = 1 };
for (int i = 1; i < vargu.Length; i++)
{
if (vargu [i] != current.value)
{
current.end = i;
_result.Add( current );
current = new ResultItem { value = vargu[i], start = i, end = i };
}
Console.WriteLine(current.value + " " + current.start + " " + current.end);
}
current.end = vargu.Length;
_result.Add(current);
Then you can dump the result as such :
foreach(ResultItem value in _result)
{
Console.WriteLine("integer {0} was placed {1} times in a row", value.value, value.end - value.start);
}
which should result in something like :
integer 2 was placed 2 times in a row
integer 3 was placed 1 times in a row
integer 4 was placed 1 times in a row
integer 5 was placed 3 times in a row
integer 6 was placed 1 times in a row
integer 9 was placed 4 times in a row
Then to find the longest sequence you can use Linq : _result.Max(r => r.end - r.start);
I've been working on the same problem myself. I tried using Mong Zhu's code above and it almost worked so I tweaked two things and it seemed to work.
Change (vargu[i] == vargu[i+1]) to (vargu[i] + 1 == vargu[i+1])
And pos = i + 1; to pos = i; and it seemed to work. My first post. I hope it's okay.
int[] arr = { 1, 2, 3, 5, 4, 3, 3, 4, 5, 6, 5, 4, 5, 6, 7, 8, 7, 5, 6, 9, 8, 7, 0 };
int pos = 0, bestPos = 0, bestLen = 0;
int len = 1;
for(int i = 0; i < arr.Length -1; i++)
{
if(arr[i] + 1 == arr[i + 1])
{
len++;
if(len > bestLen)
{
bestLen = len;
bestPos = pos;
}
}
else
{
len = 1;
pos = i ;
}
}
for( int k = bestPos; k <= bestLen + bestPos; k++)
{
Console.Write("{0}", arr[k]);
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
int finalbestsum = 0;
int bestsum = 0;
int bestcount = 0;
int count = 0;
int consval = 0;
int? consval1 = null;
string bestvalue = null;
string bestvalue1 = null;
Console.WriteLine("Enter number of columns for the array");
int col = int.Parse(Console.ReadLine());
Console.WriteLine("Enter number of rows for the array");
int row = int.Parse(Console.ReadLine());
int[,] twodimen = new int[row, col];
for (int index = 0; index < twodimen.GetLength(0); index++ )
{
for (int index1 = 0; index1 < twodimen.GetLength(1); index1++)
{
Console.WriteLine("Enter twodimen {0} {1} value",index, index1);
twodimen[index, index1] = int.Parse(Console.ReadLine());
}
}
for (int index = 0; index < twodimen.GetLength(0); index++ )
{
for (int index1 = 0; index1 < twodimen.GetLength(1)-1; index1++)
{
consval = twodimen[index,index1];
if (consval == twodimen[index, index1 + 1])
{
consval1 = twodimen[index,index1+1];
//Console.Write("{0}" + " ", consval);
bestvalue = bestvalue + Convert.ToString(" " + consval + " ");
count++;
bestsum = bestsum + consval;
}
else if (consval1 != null)
{
//Console.Write(consval1);
count++;
bestvalue = bestvalue + Convert.ToString(" " + consval1 + " ");
bestsum = bestsum + Convert.ToInt16(consval1);
Console.WriteLine();
if (bestcount < count)
{
bestvalue1 = bestvalue;
bestcount = count;
finalbestsum = bestsum;
}
else if (bestcount == count && finalbestsum < bestsum)
{
bestvalue1 = bestvalue;
bestcount = count;
finalbestsum = bestsum;
}
bestvalue = null;
count = 0;
bestsum = 0;
consval1 = null;
}
if (consval == twodimen[index, index1 + 1] && index1 == (twodimen.GetLength(1)-2))
{
bestvalue = bestvalue + Convert.ToString(" " + consval1 + " ");
//Console.Write(consval1);
bestsum = bestsum + Convert.ToInt16(consval1);
count++;
consval1 = null;
if (bestcount < count)
{
bestcount = count;
bestvalue1 = bestvalue;
finalbestsum = bestsum;
}
else if (bestcount == count && finalbestsum < bestsum)
{
bestvalue1 = bestvalue;
bestcount = count;
finalbestsum = bestsum;
}
}
}
bestvalue = null;
count = 0;
bestsum = 0;
Console.WriteLine();
//Console.WriteLine(bestcount);
}
Console.WriteLine(bestvalue1);
Console.ReadLine();
}
}
}
I am trying to make a matrix addition program through multithreading, in which i have to divide the rows of both matrices and run them in a separate thread, after that combine all the threads to get the final addition matrix.
i have made the program through single thread but unable to get that done with multiple threads.
this code is for addition with single thread
class Program
{
static void matrixAdd()
{
int[,] a = { { 1, 2, 3 }, { 4, 5, 6 }, { 7, 8, 9 } };
int[,] b = { { 4, 8, 7 }, { 6, 5, 4 }, { 3, 2, 1 } };
int[,] c = new int[3, 3];
int f = c.Length;
int i, m = 0;
int j = 0;
int n = 0;
for (i = 0; i < 3; i++)
{
Console.WriteLine(" ");
for (j = 0; j < 3; j++)
{
Console.Write(" " + a[i, j]);
}
}
Console.Write("\n");
for (m = 0; m < 3; m++)
{
Console.WriteLine(" ");
for (n = 0; n < 3; n++)
{
Console.Write(" " + b[m, n]);
}
}
Console.Write("\n");
for (int k = 0; k < 3; k++)
{
Console.WriteLine("");
for (int l = 0; l < 3; l++)
{
Console.Write(a[k, l] + b[k, l] + "\t");
}
}
}
static void Main(string[] args)
{
Thread t1 = new Thread(matrixAdd);
t1.Start();
Console.ReadLine();
}
Im trying to make an auto solve for this math:
__ + __ + __ = 30, Fill the spaces using (1, 3, 5, 7, 9, 11, 13, 15), you can also repeat the numbers.
I made this code:
int[] nums = { 1, 3, 5, 7, 9, 11, 13, 15 };
private void button1_Click(object sender, EventArgs e)
{
for (int i = 0; i < nums.Length; i++)
{
for (int j = 0; j < nums.Length; j++)
{
for (int k = 0; j < nums.Length; k++)
{
if ((nums[i] + nums[j] + nums[k]) == 30)
{
result.Text += nums[i] + nums[j] + nums[k] + "\r\n";
}
}
}
}
}
But i get this error when click the button to calculate: An unhandled exception of type 'System.IndexOutOfRangeException' occurred in app.exe
P.S.: Please do not spoil the answer for me.
Change the code
for (int k = 0; j < nums.Length; k++)
to
for (int k = 0; k < nums.Length; k++)
int[] nums = { 1, 3, 5, 7, 9, 11, 13, 15 };
private void button1_Click(object sender, EventArgs e)
{
for (int i = 0; i < nums.Length; i++)
{
for (int j = 0; j < nums.Length; j++)
{
/* check conditional statement value of k exceeds length of the num element array*/
for (int k = 0; j< nums1.Length; k++)
{
/* could have been >> for(int k=0; k < nums.Length; k++) */
if ((nums[i] + nums[j] + nums[k]) == 30)
{
result.Text += nums[i] + nums[j] + nums[k] + "\r\n";
}
}
}
}
}
:)