int[] arr = {800,11,50,771,649,770,240, 9};
int temp = 0;
for (int write = 0; write < arr.Length; write++)
{
for (int sort = 0; sort < arr.Length - 1; sort++)
{
if (arr[sort] > arr[sort + 1])
{
temp = arr[sort + 1];
arr[sort + 1] = arr[sort];
arr[sort] = temp;
}
}
Console.Write("{0} ", arr[write]);
}
All I am attempting to do is a simple bubble sort with this array. I would like to figure out why the sorting is screwed up.
In example, here is when the array is {800,11,50,771,649,770,240, 9}:
Here is what gets displayed: 11, 50, 649, 9, 649, 770, 771, 800
I am thinking that I might be missing something in the comparison.
No, your algorithm works but your Write operation is misplaced within the outer loop.
int[] arr = { 800, 11, 50, 771, 649, 770, 240, 9 };
int temp = 0;
for (int write = 0; write < arr.Length; write++) {
for (int sort = 0; sort < arr.Length - 1; sort++) {
if (arr[sort] > arr[sort + 1]) {
temp = arr[sort + 1];
arr[sort + 1] = arr[sort];
arr[sort] = temp;
}
}
}
for (int i = 0; i < arr.Length; i++)
Console.Write(arr[i] + " ");
Console.ReadKey();
This one works for me
public static int[] SortArray(int[] array)
{
int length = array.Length;
int temp = array[0];
for (int i = 0; i < length; i++)
{
for (int j = i+1; j < length; j++)
{
if (array[i] > array[j])
{
temp = array[i];
array[i] = array[j];
array[j] = temp;
}
}
}
return array;
}
public static void BubbleSort(int[] a)
{
for (int i = 1; i <= a.Length - 1; ++i)
for (int j = 0; j < a.Length - i; ++j)
if (a[j] > a[j + 1])
Swap(ref a[j], ref a[j + 1]);
}
public static void Swap(ref int x, ref int y)
{
int temp = x;
x = y;
y = temp;
}
int[] arr = { 800, 11, 50, 771, 649, 770, 240, 9 };
int temp = 0;
for (int write = 0; write < arr.Length; write++)
{
for (int sort = 0; sort < arr.Length - 1 - write ; sort++)
{
if (arr[sort] > arr[sort + 1])
{
temp = arr[sort + 1];
arr[sort + 1] = arr[sort];
arr[sort] = temp;
}
}
}
for (int i = 0; i < arr.Length; i++) Console.Write(arr[i] + " ");
Console.ReadKey();
I saw someone use this example as part of a job application test. My feedback to him was that it lacks an escape from the outer loop when the array is mostly sorted.
consider what would happen in this case:
int[] arr = {1,2,3,4,5,6,7,8};
here's something that makes more sense:
int[] arr = {1,2,3,4,5,6,7,8};
int temp = 0;
int loopCount=0;
bool doBreak=true;
for (int write = 0; write < arr.Length; write++)
{
doBreak=true;
for (int sort = 0; sort < arr.Length - 1; sort++)
{
if (arr[sort] > arr[sort + 1])
{
temp = arr[sort + 1];
arr[sort + 1] = arr[sort];
arr[sort] = temp;
doBreak=false;
}
loopCount++;
}
if(doBreak){ break; /*early escape*/ }
}
Console.WriteLine(loopCount);
for (int i = 0; i < arr.Length; i++) Console.Write(arr[i] + " ");
public static int[] BubbleSort(int[] arr)
{
int length = arr.Length();
while (length > 0)
{
int newLength = 0;
for (int i = 1; i < length; i++)
{
if (arr[i - 1] > arr[i])
{
Swap(ref arr[i - 1], ref arr[i]);
newLength = i;
}
}
length = newLength;
}
}
public static void Swap(ref int x, ref int y)
{
int temp = y;
y = x;
x = temp;
}
I wanted to add to the accepted answer something different:
Number of iterations can be reduced as well, as below.
int[] arr = { 800, 11, 50, 771, 649, 770, 240, 9 };
int temp = 0;
int arrLength = arr.Length;
for (int write = 0; write < arr.Length - 1; write++, arrLength--)
{
for (int sort = 0; sort < arrLength - 1; sort++)
{
if (arr[sort] > arr[sort + 1])
{
temp = arr[sort + 1];
arr[sort + 1] = arr[sort];
arr[sort] = temp;
}
}
}
foreach (var item in arr)
{
Console.WriteLine(item);
}
Your Console.Write("{0} ", arr[write]); is too early. You're printing the values while the sort is still in progress. For example, you're printing 9 as being index 3 in the array, yet on the very next iteration of the loop the 9 has moved to index 2 and 240 has moved to index 3... yet you're outer loop has moved forward so it prints 649 the second time and 240 never gets printed.
int[] array = new int[10] { 13, 2, 5, 8, 23, 90, 41, 4, 77, 61 };
for (int i = 10; i > 0; i--)
{
for (int j = 0; j < 9; j++)
{
if (array[j] > array[j + 1])
{
int temp = array[j];
array[j] = array[j + 1];
array[j + 1] = temp;
}
}
}
static bool BubbleSort(ref List<int> myList, int number)
{
if (number == 1)
return true;
for (int i = 0; i < number; i++)
{
if ((i + 1 < number) && (myList[i] > myList[i + 1]))
{
int temp = myList[i];
myList[i] = myList[i + 1];
myList[i + 1] = temp;
}
else
continue;
}
return BubbleSort(ref myList, number - 1);
}
Just another example but with an outter WHILE loop instead of a FOR:
public static void Bubble()
{
int[] data = { 5, 4, 3, 2, 1 };
bool newLoopNeeded = false;
int temp;
int loop = 0;
while (!newLoopNeeded)
{
newLoopNeeded = true;
for (int i = 0; i < data.Length - 1; i++)
{
if (data[i + 1] < data[i])
{
temp = data[i];
data[i] = data[i + 1];
data[i + 1] = temp;
newLoopNeeded = false;
}
loop++;
}
}
}
Bubble sort with sort direction -
using System;
public class Program
{
public static void Main(string[] args)
{
var input = new[] { 800, 11, 50, 771, 649, 770, 240, 9 };
BubbleSort(input);
Array.ForEach(input, Console.WriteLine);
Console.ReadKey();
}
public enum Direction
{
Ascending = 0,
Descending
}
public static void BubbleSort(int[] input, Direction direction = Direction.Ascending)
{
bool swapped;
var length = input.Length;
do
{
swapped = false;
for (var index = 0; index < length - 1; index++)
{
var needSwap = direction == Direction.Ascending ? input[index] > input[index + 1] : input[index] < input[index + 1];
if (needSwap)
{
var temp = input[index];
input[index] = input[index + 1];
input[index + 1] = temp;
swapped = true;
}
}
} while (swapped);
}
}
This is what I wrote using recursive methods:
public static int[] BubbleSort(int[] input)
{
bool isSorted = true;
for (int i = 0; i < input.Length; i++)
{
if (i != input.Length - 1 && input[i] > input[i + 1])
{
isSorted = false;
int temp = input[i];
input[i] = input[i + 1];
input[i + 1] = temp;
}
}
return isSorted ? input : BubbleSort(input);
}
It does the same in a more elegant way.
var arrayValues = new[] { 99, 12, 11, 300, 400, 10, 9, 3, 6, 5, 7, 8};
for (var mainLoop = 0; mainLoop < arrayValues.Length; mainLoop++)
{
for (var innerLoop = mainLoop + 1; innerLoop < arrayValues.Length; innerLoop++)
{
if (arrayValues[mainLoop] <= arrayValues[innerLoop])
{
continue;
}
var temp = arrayValues[mainLoop];
arrayValues[mainLoop] = arrayValues[innerLoop];
arrayValues[innerLoop] = temp;
}
}
So i did mine as a recursive function (no need for the nested loop), perhaps someone could comment if this is inefficient (when compared to the other solutions).
public static int[] BubbleSort(int[] arrayOfValues)
{
var swapOccurred = false;
for (var i = 0; i < arrayOfValues.Length; i++)
{
if (i == arrayOfValues.Length - 1)
continue;
if (arrayOfValues[i] > arrayOfValues[i + 1])
{
//swap values
var current = arrayOfValues[i];
var next = arrayOfValues[i + 1];
arrayOfValues[i] = next;
arrayOfValues[i + 1] = current;
swapOccurred = true;
}
}
if (swapOccurred)
{
// keep going until no further swaps are required:
BubbleSort(arrayOfValues);
}
return arrayOfValues;
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace Practice {
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Enter the size");
int n = Convert.ToInt32(Console.ReadLine());
int[] mynum = new int[n];
Console.WriteLine("Enter the Numbers");
for (int p = 0; p < n;p++ )
{
mynum[p] = Convert.ToInt32(Console.ReadLine());
}
Console.WriteLine("The number are");
foreach(int p in mynum)
{
Console.WriteLine(p);
}
for (int i = 0; i < n;i++ )
{
for(int j=i+1;j<n;j++)
{
if(mynum[i]>mynum[j])
{
int x = mynum[j];
mynum[j] = mynum[i];
mynum[i] = x;
}
}
}
Console.WriteLine("Sortrd data is-");
foreach(int p in mynum)
{
Console.WriteLine(p);
}
Console.ReadLine();
}
} }
int[] arr = { 800, 11, 50, 771, 649, 770, 240, 9 };
for (int i = 0; i < arr.Length; i++)
{
for (int j = i; j < arr.Length ; j++)
{
if (arr[j] < arr[i])
{
int temp = arr[i];
arr[i] = arr[j];
arr[j] = temp;
}
}
}
Console.ReadLine();
public void BubbleSortNum()
{
int[] a = {10,5,30,25,40,20};
int length = a.Length;
int temp = 0;
for (int i = 0; i <length; i++)
{
for(int j=i;j<length; j++)
{
if (a[i]>a[j])
{
temp = a[j];
a[j] = a[i];
a[i] = temp;
}
}
Console.WriteLine(a[i]);
}
}
Related
I have task to create merge sort algorithm in c# for 2d array. Array looks like that
X1 Y1
X2 Y2
…
Xn Yn
I need to take array from file and sort the lines in ascending x order, also the program should check for the absence of pairs of coordinates with the same X values and at the same time different Y values, when array was sorted, the programm should write it in the file.
I had created algorithm for 1d array, but can't understand how to rewrite it for 2d array, here is my code, please help me
using System;
using System.IO;
using System.Collections;
using System.Collections.Generic;
class Program
{
//array merging
static void Merge(int[] num, int lowIndex, int middleIndex, int highIndex)
{
var left = lowIndex;
var right = middleIndex + 1;
var tempArray = new int[highIndex - lowIndex + 1];
var index = 0;
while ((left <= middleIndex) && (right <= highIndex))
{
if (num[left] < num[right])
{
tempArray[index] = num[left];
left++;
}
else
{
tempArray[index] = num[right];
right++;
}
index++;
}
for (var j = left; j <= middleIndex; j++)
{
for (var i=0;;) {
tempArray[index] = num[j];
index++; }
}
for (var j = right; j <= highIndex; j++)
{
for (var i = 0; ;)
{
tempArray[index] = num[j];
index++;
}
}
for (var j = 0; j < tempArray.Length; j++)
{
for(var i=0; ;)
{
num[lowIndex + j] = tempArray[j];
}
}
}
//merge sorting
static int[] MergeSort(int[] num, int lowIndex, int highIndex)
{
if (lowIndex < highIndex)
{
var middleIndex = (lowIndex + highIndex) / 2;
MergeSort(num, lowIndex, middleIndex);
MergeSort(num, middleIndex + 1, highIndex);
Merge(num, lowIndex, middleIndex, highIndex);
}
return num;
}
public static int[] MergeSort(int[] num)
{
return MergeSort(num, 0, num.Length - 1);
}
static void Main(string[] args)
{
Console.WriteLine("Merge sorting");
string[] lines = File.ReadAllLines(#"C:\Users\glebk\source\repos\ConsoleApp18\ConsoleApp18\file.txt");
int[,] num = new int[lines.Length, lines[0].Split(' ').Length];
for (int i = 0; i < lines.Length; i++)
{
string[] temp = lines[i].Split(' ',',');
for (int j = 0; j < temp.Length; j++)
{
num[i, j] = Convert.ToInt32(temp[j]);
Console.Write(num[i, j]+" ");
}
Console.ReadKey();
}
Console.WriteLine("Sorted array: {0}", string.Join(",", MergeSort(num)));
}
}`
The most direct way of doing it is replacing
tempArray[index] = num[left];
with something like this
static void CopyLine(int[,] destArr, int destIndex, int[,] sourceArr, int sourceIndex)
{
for (int i = 0; i < destArr.GetLength(1); ++i)
{
destArr[destIndex, i] = sourceArr[sourceIndex, i];
}
}
here is the whole code
static void CopyLine(int[,] destArr, int destIndex, int[,] sourceArr, int sourceIndex)
{
for (int i = 0; i < destArr.GetLength(1); ++i)
{
destArr[destIndex, i] = sourceArr[sourceIndex, i];
}
}
//array merging
static void Merge(int[,] num, int lowIndex, int middleIndex, int highIndex)
{
var left = lowIndex;
var right = middleIndex + 1;
var tempArray = new int[highIndex - lowIndex + 1, num.GetLength(1)];
var index = 0;
while ((left <= middleIndex) && (right <= highIndex))
{
if (num[left, 0] < num[right, 0])
{
CopyLine(tempArray, index, num, left);
left++;
}
else
{
CopyLine(tempArray, index, num, right);
right++;
}
index++;
}
for (var j = left; j <= middleIndex; j++)
{
CopyLine(tempArray, index, num, j);
index++;
}
for (var j = right; j <= highIndex; j++)
{
CopyLine(tempArray, index, num, j);
index++;
}
for (var j = 0; j < tempArray.GetLength(0); j++)
{
CopyLine(num, lowIndex + j, tempArray, j);
}
}
//merge sorting
static void MergeSort(int[,] num, int lowIndex, int highIndex)
{
if (lowIndex < highIndex)
{
var middleIndex = (lowIndex + highIndex) / 2;
MergeSort(num, lowIndex, middleIndex);
MergeSort(num, middleIndex + 1, highIndex);
Merge(num, lowIndex, middleIndex, highIndex);
}
}
public static void MergeSort(int[,] num)
{
MergeSort(num, 0, num.GetLength(0) - 1);
}
static void WriteArray(string description, int[,] arr)
{
Console.WriteLine(description);
for (int i = 0; i < arr.GetLength(0); i++)
{
for (int j = 0; j < arr.GetLength(1); j++)
{
Console.Write(arr[i, j] + " ");
}
Console.WriteLine();
}
Console.WriteLine();
}
static void Main(string[] args)
{
int[,] num = new int[,] { { 3, 5 }, { 1, 10 }, { 7, 3 }, { 2, 1 }, { 5, 2 } };
WriteArray("Original array:", num);
MergeSort(num);
WriteArray("Sorted array:", num);
Console.ReadKey();
}
There are also other options, you can fuse two int values into one long value and sort it as 1D array. But it would need additional steps.
I am trying to implement a step counter into my bubble sort algorithm, but I don't know how to display the counter at the end of the sorting algorithm. If anyone could explain how I should go about this that would be great. Thank You.
My current code: (Bubble Sort):
static int[] bubbleSort(int[] arr, int n)
{
int stepCount = 0; // <- Counter to return and display
for (int i = 0; i < n - 1; i++)
{
for (int j = 0; j < n - 1 - i; j++)
{
if (arr[j + 1] < arr[j])
{
int temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
stepCount++;
}
}
return arr;
}
public static void DisplayArrayBubble(int[] arr)
{
foreach (int i in arr)
{
Console.Write(i.ToString() + " ");
}
}
Why not just return int - number of steps? I.e.
// arr : will be sorted
// return : number of steps
static int bubbleSort(int[] arr) {
if (null == arr)
return 0;
int stepCount = 0;
for (int i = 0; i < arr.Length - 1; i++)
for (int j = 0; j < arr.Length - 1 - i; j++)
if (arr[j + 1] < arr[j]) {
int temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
stepCount += 1;
}
return stepCount;
}
Demo:
int[] sample = new int[] {1, 5, 4, 3, 2, 7};
int steps = bubbleSort(sample);
Console.WriteLine($"Sorted [{string.Join(", ", sample)}] in {steps} steps");
Outcome:
Sorted [1, 2, 3, 4, 5, 7] in 6 steps
There a plethora of ways but one is to make a custom class to hold both pieces of information that you need:
public class BubbleObject
{
public int[] arr { get; set; }
public int stepCount { get; set; }
}
Then adjust the code you have to use that object:
static BubbleObject bubbleSort(int[] arr, int n)
{
int stepCount = 0;
for (int i = 0; i < n - 1; i++)
{
for (int j = 0; j < n - 1 - i; j++)
{
if (arr[j + 1] < arr[j])
{
int temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
stepCount++;
}
}
BubbleObject bo = new BubbleObject() { arr=arr, stepCount=stepCount}
return bo;
}
public static void DisplayArrayBubble(BubbleObject bo)
{
Console.WriteLine("Number of Steps = " + bo.stepCount);
foreach (int i in bo.arr)
{
Console.Write(i.ToString() + " ");
}
}
That should do it. There are other ways as well.
I am implementing the NEH algorithm following this slide and video:
http://mams.rmit.edu.au/b5oatq61pmjl.pdf
https://www.youtube.com/watch?v=TcBzEyCQBxw
My problem during the test is the variable Sorted_list got changed which cause different results from what I expect:
This the portion where I have the problem but I couldn't know what it changes it(I used breakpoints and watch variable window):
for (int i = 0; i < kmsList.Count; i++)
{
for (int j = 0; j < kmsList[i].Length - 1; j++)
{
/*
*
* HERE Sorted_list GET MODIFIED UNEXPECTEDLY
*/
if (i == 0 && j == 0)
kmsList[0][0] = Sorted_list[0][0];
else if (i == 0)
kmsList[0][j] = kmsList[0][j - 1] + Sorted_list[0][j];
else if (j == 0)
kmsList[i][0] = kmsList[i - 1][0] + Sorted_list[i][0];
}
}
Complete implementation:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace FINAL_NEH
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("entre the nmbr of jobs : ");
string row = Console.ReadLine();
Console.WriteLine("entre the nmbr of machines : ");
string column = Console.ReadLine();
int job = int.Parse(row.ToString());
int machine = int.Parse(column.ToString());
List<int[]> list = new List<int[]>();
// read the nmbrs and put it in list-----------------------------------------------------
for (int i = 0; i < job; i++)
{
list.Add(new int[machine + 1]);
for (int j = 0; j < machine; j++)
{
list[i][j] = int.Parse(Console.ReadLine());
}
list[i][list[i].Length - 1] = int.Parse((i + 1).ToString()); //Last Elemnt Is Job Number-
}
// show the list----------------------------------------------------------------------------
for (int i = 0; i < job; i++)
{
for (int j = 0; j < machine + 1; j++)
{
Console.Write("\t" + "[" + list[i][j] + "]");
}
Console.WriteLine();
}
// sort the list------------------------------------------------------------------------------
for (int i = 0; i < list.Count; i++)
{
for (int j = i + 1; j < list.Count; j++)
{
int sumI = 0, sumJ = 0;
for (int a = 0; a < list[i].Length - 1; a++)
{
sumI += list[i][a];
}
for (int a = 0; a < list[j].Length - 1; a++)
{
sumJ += list[j][a];
}
if (sumI < sumJ)
{
int[] temp = new int[int.Parse(job.ToString())];
temp = list[i];
list[i] = list[j];
list[j] = temp;
}
}
}
Console.Write("\n\n-----------------after sorting ------------------------------------\n\n");
// shaw the list after sorting------------------------------------------
for (int i = 0; i < job; i++)
{
for (int j = 0; j < machine + 1; j++)
{
Console.Write("\t" + "[" + list[i][j] + "]");
}
Console.WriteLine();
}
// clculate the maxpane of the first 2 jobs---------------------------------------
List<int[]> initMaxpane = new List<int[]>();
initMaxpane.Add((int[])list[0].Clone());
initMaxpane.Add((int[])list[1].Clone());
// calculer maxspan of first jobs..............................................
for (int i = 0; i < initMaxpane.Count; i++)
{
for (int j = 0; j < initMaxpane[i].Length - 1; j++)
{
if (j == 0 && i == 0)
initMaxpane[0][0] = list[i][j];
else if (i == 0)
initMaxpane[0][j] = (int)(initMaxpane[0][j - 1] + list[0][j]);
else if (j == 0)
initMaxpane[i][0] = (int)(initMaxpane[i - 1][0] + list[i][0]);
}
}
for (int i = 1; i < initMaxpane.Count; i++)
{
for (int j = 1; j < initMaxpane[i].Length - 1; j++)
{
if ((initMaxpane[i][j - 1] > initMaxpane[i - 1][j]))
initMaxpane[i][j] = (int)(initMaxpane[i][j - 1] + list[i][j]);
else
initMaxpane[i][j] = (int)(initMaxpane[i - 1][j] + list[i][j]);
}
}
int Cmax = initMaxpane[initMaxpane.Count - 1][initMaxpane[initMaxpane.Count - 1].Length - 2];
Console.WriteLine("\n\n-------the maxpane offirst jobs----------");
for (int i = 0; i < initMaxpane.Count; i++)
{
for (int j = 0; j < initMaxpane[i].Length; j++)
{
Console.Write("\t" + "[" + initMaxpane[i][j] + "]");
}
Console.WriteLine();
}
List<int[]> initMaxpane2 = new List<int[]>();
initMaxpane2.Add(list.ElementAt(1));
initMaxpane2.Add(list.ElementAt(0));
// calculer maxspan of first jobs reverse..............................................
for (int i = 0; i < initMaxpane2.Count; i++)
{
for (int j = 0; j < initMaxpane2[i].Length - 1; j++)
{
if (j == 0 && i == 0)
initMaxpane2[0][0] = list[i][j];
else if (i == 0)
initMaxpane2[0][j] = (int)(initMaxpane2[0][j - 1] + list[0][j]);
else if (j == 0)
initMaxpane2[i][0] = (int)(initMaxpane2[i - 1][0] + list[i][0]);
}
}
for (int i = 1; i < initMaxpane2.Count; i++)
{
for (int j = 1; j < initMaxpane2[i].Length - 1; j++)
{
if ((initMaxpane2[i][j - 1] > initMaxpane2[i - 1][j]))
initMaxpane2[i][j] = (int)(initMaxpane2[i][j - 1] + list[i][j]);
else
initMaxpane2[i][j] = (int)(initMaxpane2[i - 1][j] + list[i][j]);
}
}
int Cmax2 = initMaxpane2[initMaxpane2.Count - 1][initMaxpane2[initMaxpane2.Count - 1].Length - 2];
Console.WriteLine("\n\n-------the maxpane of first jobs (reverse)----------");
for (int i = 0; i < initMaxpane2.Count; i++)
{
for (int j = 0; j < initMaxpane2[i].Length; j++)
{
Console.Write("\t" + "[" + initMaxpane2[i][j] + "]");
}
Console.WriteLine();
}
List<int[]> MaxpaneList = new List<int[]>();
if (Cmax > Cmax2)
{
MaxpaneList.Add((int[])list[1].Clone());
MaxpaneList.Add((int[])list[0].Clone());
}
else
{
MaxpaneList.Add((int[])list[0].Clone());
MaxpaneList.Add((int[])list[1].Clone());
}
List<int[]> bestSequenceList = null;
List<int[]> kmsList = null;
List<int[]> Sorted_list = list.ToList();
int bestCma = 0;
//int maxspan = 0;
for (int jo = 2; jo < job; jo++)
{
for (int ins = 0; ins <= MaxpaneList.Count; ins++)
{
MaxpaneList.Insert(ins, list[jo]);
kmsList = MaxpaneList.ToList();
int Cma = 0;
for (int i = 0; i < kmsList.Count; i++)
{
for (int j = 0; j < kmsList[i].Length - 1; j++)
{
/*
*
* HERE Sorted_list GET MODIFIED UNEXPECTEDLY
*/
if (i == 0 && j == 0)
kmsList[0][0] = Sorted_list[0][0];
else if (i == 0)
kmsList[0][j] = kmsList[0][j - 1] + Sorted_list[0][j];
else if (j == 0)
kmsList[i][0] = kmsList[i - 1][0] + Sorted_list[i][0];
}
}
for (int i = 1; i < kmsList.Count; i++)
{
for (int j = 1; j < kmsList[i].Length - 1; j++)
{
if ((kmsList[i][j - 1] > kmsList[i - 1][j]))
kmsList[i][j] = kmsList[i][j - 1] + Sorted_list[i][j];
else
kmsList[i][j] = kmsList[i - 1][j] + Sorted_list[i][j];
}
}
Cma = kmsList[kmsList.Count - 1][kmsList[kmsList.Count - 1].Length - 2];
Console.WriteLine("\n\n\n------- the maxpane sequence ----------");
for (int i = 0; i < MaxpaneList.Count; i++)
{
for (int j = 0; j < MaxpaneList[i].Length; j++)
{
Console.Write("\t" + "[" + MaxpaneList[i][j] + "]");
}
Console.WriteLine();
}
Console.WriteLine("MAX : " + Cma + "\n\n\n");
if (ins == 0)
{
bestCma = Cma;
}
if (jo == 2 && ins == 0)
{
bestSequenceList = MaxpaneList.ToList();
bestCma = Cma;
}
else
{
if (bestCma > Cma)
{
bestSequenceList = MaxpaneList.ToList();
bestCma = Cma;
}
}
MaxpaneList.RemoveAt(ins);
}
MaxpaneList = bestSequenceList.ToList();
}
Console.ReadLine();
}
}
}
The issue lies in the following code (snippet):
List<int[]> Sorted_list = list.ToList();
ToList will create a new list, but because in this case int[] is a reference type then the new list will contain references to the same arrays as the original list.
Updating a value (of an array) referenced in the new list will also affect the equivalent value in the original list.
kmsList[0][0] = Sorted_list[0][0];
The solution is to create a real copy of 'list' and its items (in this case int[]):
List<int[]> Sorted_list = list.ConvertAll(myArray => (int[])myArray.Clone());
This piece of code clones all arrays within the list to a new variable Sorted_list.
A useful link that explains the difference between value and reference types is: https://msdn.microsoft.com/en-us/library/t63sy5hs.aspx
Reference Types
A reference type contains a pointer to another memory location that holds the data.
Reference types include the following:
String
All arrays, even if their elements are value types Class
types, such as Form
Delegates
When you create a List<> (or any other container) from another container (as you do when you call list.ToList()) you do not create copies of all of the elements in the container. You create new references to the items in the list that you're copying. In CS parlance it's a shallow copy and not a deep copy.
So, if you do this:
int[] ia = new[] {0, 1, 2, 3, 4};
int[] ib = new[] {5, 6, 7, 8, 9};
List<int[]> la = new List<int[]>() { ia, ib };
List<int[]> lb = la.ToList();
Both lists refer to the same two arrays, and if you change one array like this:
la[1][4] = 10;
Then lb[1][4] will also be 10 because the two lists each contain the same arrays. Copying the list does not copy the elements in the list.
I couldn't get it to work, I am trying to arrange the values of the array in ascending order by using for loop.
int[] arr = new int[5] { 5, 6, 2, 4, 1 };
for (int i = 0; i <= arr.Length; i++)
{
if (arr[i] > arr[i + 1])
{
int temp = arr[i + 1];
arr[i] = arr[i + 1];
arr[i] = temp;
}
Console.Write(arr[i]);
}
I am assuming that you are not using Array.Sort because you are doing this as a learning exercise; there is no other way to avoid this very common library function.
The reason your algorithm does not work is that it is not enough to go through an array once, and swap items that are out of order. Try doing this as a mental experiment, when the array is almost sorted, but the first element is at the end, like this:
2 3 4 5 6 7 1
A single path would bring you closer, but it wouldn't bring you all the way to a sorted array:
2 3 4 5 6 1 7
As you can see, you have to repeat this process multiple times, until the array is sorted. How do you know that the array is sorted? You know that when the entire inner loop did not have a single swap.
Here is how you can implement this:
bool didSwap;
do {
didSwap = false;
for (int i = 0; i < arr.Length-1; i++)
{
if (arr[i] > arr[i + 1])
{
int temp = arr[i + 1];
arr[i + 1] = arr[i];
arr[i] = temp;
didSwap = true;
}
}
} while (didSwap);
for (int i = 0; i != arr.Length ; i++) {
Console.Write(arr[i]);
}
Note several changes from your code:
The printing is done in the separate loop, after the sorting is complete
The loop goes to arr.length-1, not to arr.length, because otherwise your last check will go outside the bounds of the array.
This sorting algorithm is called Bubble Sort. There are various optimizations to this algorithm that can make it go slightly faster.
In general, bubble sort is among the slower sorting algorithms. When the number of items to sort is high, you should consider an advanced algorithm, or use the library implementation.
int[] Array = { 11, 33, 5, -3, 19, 8, 49 };
int temp;
for (int i = 0; i < Array.Length - 1; i++)
{
for (int j = i + 1; j < Array.Length; j++)
{
if (Array[i] > Array[j])
{
temp = Array[i];
Array[i] = Array[j];
Array[j] = temp;
}
}
}
Console.Write("Sorted:");
foreach (int sort in Array)
Console.Write("{0} ", sort);
If you want to make your own sorting, then it's not enough to just loop through the items once and swap them. The closest to that is the bubble sort algorithm, where you loop over the array repeatedly until there is no more items to swap:
int[] arr = new int[5] { 5, 6, 2, 4, 1 };
bool swapped = true;
while (swapped) {
swapped = false;
for (int i = 0; i < arr.Length - 1; i++) {
if (arr[i] > arr[i + 1]) {
swapped = true;
int temp = arr[i + 1];
arr[i] = arr[i + 1];
arr[i] = temp;
}
}
}
for (int i = 0; i < arr.Length - 1; i++) {
Console.Write(arr[i]);
}
There are also built in methods to sort data, which is easier to use, more efficient, and already thoroughly tested:
int[] arr = new int[5] { 5, 6, 2, 4, 1 };
Array.Sort(arr);
Use Linq Order by:
int[] arr = new int[5] { 5, 6, 2, 4, 1 };
int[] ascOrderedArray = (from i in arr orderby i ascending select i).ToArray();
I think it could be easy and why do you need for loop.
using System;
namespace bubble_sort
{
class Program
{
static void Main(string[] args)
{
Program p = new Program();
int[] arr = new int[50];
int n;
Console.WriteLine("Enter no of elements you want to store in an array");
n = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("Enter elements in an array");
for (int i = 1; i <= n; i++)
{
arr[i] = Convert.ToInt32(Console.ReadLine());
}
p.bubblesort(arr, n);
Console.ReadKey();
}
public void bubblesort(int[] arr, int n)
{
int temp;
for (int i = 1; i <= n; i++)
{
for (int j = 1; j <= n - i; j++)
{
if (arr[j] > arr[j + 1])
{
temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
}
}
Console.WriteLine("Array after sorting");
for (int i = 1; i <= n; i++)
{
Console.WriteLine(arr[i]);
}
}
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
namespace basicsorting
{
public class Program
{
public static void Main(string[] args)
{
int i2, k, j;
Console.WriteLine("How many elements you want to sort? ");
i2 = Convert.ToInt32(Console.ReadLine());
int[] values = new int[i2];
int n1 = 0;
int n = 0; ;
int i;
Console.WriteLine("Enter the elements of array {0}", n1);
for (i = 0; i < i2; i++)
{
Console.WriteLine("Enter the elements of array {0}");
n = Convert.ToInt32(Console.ReadLine());
Convert.ToInt32(values[i] = n);
}
for (i = 0; i < i2; i++)
{
k = Convert.ToInt32(values[i]);
for (j = i - 1; j >= 0 && k < values[j]; j--)
values[j + 1] = values[j];
values[j + 1] = k;
}
for (i = 0; i < i2; i++)
{
Console.WriteLine("sorting elements {0}", values[i]);
}
Console.ReadLine();
}
}
}
int[] array = new int[] { 8, 9, 5, 6, 7, 4, 3, 2, 1 };
int[] outPut = new int[] { };
int temp = 0;
for (int i = 0; i < array.Length; i++)
{
for (int j = 0; j < array.Length; j++)
{
var first = array[i];
var second = array[j];
if (array[i] < array[j]) {
temp = first;
array[i] = second;
array[j] = temp;
}
}
}
foreach (var item in array) {
Console.WriteLine(item);
}
Console.ReadKey();
}
foreach (var item in array) {
Console.WriteLine(item);
}
Console.ReadKey();
int temp = 0;
int[] arr = new int[] { 5, 6, 2, 4, 1 };
for (int i = 0; i <= arr.Length - 1; i++)
{
for (int j = i + 1; j <= arr.Length - 1; j++)
{
if (arr[i] > arr[j]) //> Asecnding Order < Desending Order
{
temp = arr[i];
arr[i] = arr[j];
arr[j] = temp;
}
}
Console.Write(arr[i]);
}
Console.ReadLine();
public int[] sortArray(params int[] numbers)
{
for(int i = 0; i < numbers.Length; i++)
{
for(int j = i + 1; j < numbers.Length; j++)
{
if (numbers[i] < numbers[j])
{
continue;
}else if (numbers[i] > numbers[j])
{
int temp = numbers[i];
numbers[i] = numbers[j];
numbers[j] = temp;
}
}
}
return numbers;
}
You should do like :
int[] arr = new int[5] { 5, 6, 2, 4, 1 };
for (int i = 0; i < arr.Length-1; i++)
{
if (arr[i] < arr[i + 1])
{
int temp = arr[i];
arr[i] = arr[i + 1];
arr[i + 1] = temp;
}
}
// to verify sorted Array
for (int i = 0; i < arr.Length; i++)
{
console.write( arr[i].ToString());
}
For last 1 you need not to check it will be automatically ordered.
#Jon Skeet They wanted to use a for loop.
There are numerous types of sorts. The simplest is Bubble Sort.
int[] arr = new int[5] { 5, 6, 2, 4, 1 };
//bubble sort
for (int i = arr.Length - 1; i > 0; i--)
{
for (int j = 0; j <= i - 1; j++)
{
if (arr[j] > arr[j + 1])
{
int highValue = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = highValue;
}
}
}
foreach(int i in arr) Console.Write(i);
I was just asking if there is a simple way of doing this.
i.e. Replacing two consecutive cell with one cell having different value.
For ex: - if my array =[0,3,1,2,3,4], and i want to replace index 0,and 1 with the value 5
to become like this array=[5,1,2,3,4]
Can you guys suggest some simple way for doing this.
i do this code but there is something wrong:
int J = 0;
if (max != 1)
{
for (int iii = 0; iii < output.Length -1; iii++)
{
if ((output[iii] == imax) && (output[iii + 1] == jmax))
{
temp = temp + 1;
output[J] = Convert.ToByte(temp);
J = J + 1;
iii = iii + 1;
}
else
{
output[J] = output[iii];
J = J + 1;
output[J] = output[iii + 1];
}
}
}
because when i want to check the 2 consecutive index ,i want to pass them to the anther 2 index
If you care about performance you want to do as little operations that can harm performance. Try this extension method:
public static int[] ReplaceConsecutiveCells(this int[] array, int startIndex, int replaceWith)
{
int[] targetArray = new int[array.Length - 1];
for (int i = 0; i < array.Length; i++)
{
if (i < startIndex)
{
targetArray[i] = array[i];
}
else if (i == startIndex)
{
targetArray[i] = replaceWith;
}
else if (i == startIndex + 1)
{
// no action
}
else
{
targetArray[i - 1] = array[i];
}
}
return targetArray;
}
Use it like this:
array = array.ReplaceConsecutiveCells(0, 5);
int[] array = new int[] { 0, 3, 1, 2, 3, 4 };
List<int> list = array.ToList();
list.RemoveRange(0,2);
list.Insert(0, 5);
array = list.ToArray();
Yet another variant
int[] array = new int[] { 0, 3, 1, 2, 3, 4 };
Array.Reverse(array);
Array.Resize(ref array, 5);
Array.Reverse(array);
array[0] = 5;
do
{
RNG_NXT =RNG +1;
for (int iii = 0; iii <Nold -1; iii++)
{
if ((output[iii] == imax) && (output[iii + 1] == jmax))
{
output[J] = Convert.ToByte(RNG_NXT);
J = J + 1;
iii = iii + 1;
}
else
{
output[J] = output[iii];
J = J + 1;
}
}
RNG++;
}
while( RNG < RNG_MAX) ;