I'm trying to translate a C++ method that uses a homegrown form of encryption. But I don't understand what Buffer[x] and Input[x] are doing? As a C# developer (beginner at that), It looks like they should be arrays but they aren't declared as such. Can anyone explain please?
The input string "{x;ƒ~sq{j|tLtuq" translates to "MY SOFTWARE INC"
AnsiString __fastcall TMyMain::Decode(AnsiString Input)
{
int error[] = { 2, 9, 5, 4, 1, 6, 7, 12, 19, 3, 1, 0, 21, 17 };
int x;
AnsiString Buffer = Input;
if (encoded!=0)
{
int count = 0;
for(x=Input.Length();x>=1;x--)
{
Buffer[x] = Input[x]-48+error[count];
count++;
if (count>=14)
count=0;
}
}
return Buffer;
}
Here's how I'd translate it. Note I have no idea where encoded comes from, so I left that out. The trick is to use a StringBuilder for your buffer so you can mutate the characters, another options would be a char array.
public static string Decode(string input)
{
int[] error = { 2, 9, 5, 4, 1, 6, 7, 12, 19, 3, 1, 0, 21, 17 };
StringBuilder buffer = new StringBuilder(input);
int count = 0;
for (int x = input.Length - 1; x >= 0; x--) {
buffer[x] = (char)(input[x] - 48 + error[count]);
count++;
if (count >= 14)
count = 0;
}
return buffer.ToString();
}
This however outputs "MY TOFTWARE INC" for the input "{x;ƒ~sq{j|tLtuq", so I'm not exactly sure if the issue is with your string or the code.
I've come up with this, but it doesn't quite return the expected results. Are you sure of the input string?
Input and output is string.
var encoded = true;
var input = "{x;ƒ~sq{j|tLtuq";
var output = Decode(input);
Console.WriteLine($"input \"{input}\", output \"{output}\"");
private static string Decode(string input)
{
int[] error = { 2, 9, 5, 4, 1, 6, 7, 12, 19, 3, 1, 0, 21, 17 };
var buffer = new char[input.Length];
if (encoded)
{
int count = 0;
for(var x=input.Length-1;x>=0;x--)
{
buffer[x] = (char) ((Convert.ToInt16(input[x])-48 + error[count]) & 0xFF);
count++;
if (count>=error.Length)
count=0;
}
return new string(buffer)
}
return input;
}
Calling this writes the following to the console:
input "{x;ƒ~sq{j|tLtuq", output "MY bOFTWARE INC"
I don't know if it helps but after some reverse engeneering you could use the following errors array (with the StringBuilder implementation) to dispaly the proper information.
int[] error = { 2, 9, 5, 4, 1, 6, 7, 12, 19, 3, 1, -6, 21, 17 };//MY SOFTWARE INC
It has to do with how characters were encoded in c++ vs c# so you could try to play around with System.Text.Encoding.
Related
I have an array A with values: {10, 12, 6, 14, 7} and I have an array B with values: {1, 8, 2}
I have sorted the array B in an ascending order and then combined both the arrays in a new array C as shown in the following code -
static void Main()
{
int A[] = {10, 12, 6, 14, 7};
int B[] = {1, 8, 2};
Array.Sort(B);
var myList = new List<int>();
myList.AddRange(A);
myList.AddRange(B);
int[] C = myList.ToArray();
//need values in this order: 10, 1, 12, 2, 8, 6, 14, 7
}
Now I wanna sort the array C this way: 10, 1, 12, 2, 8, 6, 14, 7
The smaller values should be between the larger values, for ex: 1 is between 10 and 12, 2 is between 12 and 8, 6 is between 8 and 14, so on and so forth.
How can I do this in C#?
If recursion is needed, how can I add it to the code?
What I understood from your example is that you are trying to alternate between large and small values such that the small value is always smaller than the number to the left and the right. I wrote an algorithm below to do that however it does not yield the exact same results you requested. However I believe it does meet the requirement.
The straggling 7 is considered the next smallest number in the sequence but there is no number that follows it. Based on your example it appears that is allowed.
To Invoke
int[] A = { 10, 12, 6, 14, 7 };
int[] B = { 1, 8, 2 };
var result = Sort(A, B);
Sort Method
public static int[] Sort(int[] A, int[] B)
{
var result = new int[A.Length + B.Length];
var resultIndex = 0;
Array.Sort(A);
Array.Sort(B);
//'Pointer' for lower index, higher index
var aLeft = 0;
var aRight = A.Length-1;
var bLeft = 0;
var bRight = B.Length - 1;
//When Items remain in both arrays
while (aRight >= aLeft && bRight >= bLeft)
{
//Add smallest
if (resultIndex % 2 > 0)
{
if (A[aLeft] < B[bLeft])
result[resultIndex++] = A[aLeft++];
else
result[resultIndex++] = B[bLeft++];
}
//Add largest
else
{
if (A[aRight] > B[bRight])
result[resultIndex++] = A[aRight--];
else
result[resultIndex++] = B[bRight--];
}
}
//When items only in array A
while (aRight >= aLeft)
{
//Add smallest
if (resultIndex % 2 > 0)
result[resultIndex++] = A[aLeft++];
//Add largest
else
result[resultIndex++] = A[aRight--];
}
//When items remain only in B
while (bRight >= bLeft)
{
//Add smallest
if (resultIndex % 2 > 0)
result[resultIndex++] = B[bLeft++];
//Add largest
else
result[resultIndex++] = B[bRight--];
}
return result;
}
Result
[14, 1, 12, 2, 10, 6, 8, 7]
So I want to simulate a roulette to proof that the House always wins.
I’m almost done but I stumbled upon a problem. I’m able to enter how many times to roll and it works fine. I get different numbers and it also tells me if red or black.
However the number 0 won’t show up in the results. I don’t know how to fix this, the code looks fine to me.
Code:
namespace ConsoleApplication9
{
class Program
{
static void Main(string[] args)
{
int[] Null = new int[1] { 0 };
int[] Rote = new int[18] { 1, 3, 5, 7, 9, 12, 14, 16, 18, 19, 21, 23, 25, 27, 30, 32, 34, 36 };
int[] Schwarze = new int[18] { 2, 4, 6, 8, 10, 11, 13, 15, 17, 20, 22, 24, 26, 28, 29, 31, 33, 35 };
// 0 ohne Tischlimit
var list = new List<int>();
list.AddRange(Rote);
list.AddRange(Schwarze);
list.AddRange(Null);
Console.WriteLine("Wie oft soll gespielt werden?");
int Anzahl = Convert.ToInt32(Console.ReadLine());
Random zufall = new Random();
for (int i = 0; i < Anzahl; ++i)
{
int number = list[zufall.Next(0, list.Count - 1)];
if (Rote.Contains(number))
{
Console.WriteLine("Rot" + number);
}
if (Schwarze.Contains(number))
{
Console.WriteLine("Schwarz" + number);
}
if (Null.Contains(number))
{
Console.WriteLine("Null" + number);
}
}
Console.ReadLine();
}
}
Ok, the thing is that Random.Next Method (Int32, Int32) uses upper bound as exclusive. So you have 0 as last element of list. And passing list.Count - 1 results in generating values between 0 and list.Count - 2. So the last element of the list is just ignored as you will never generate the last index list.Count - 1. You need to pass list.Count to Next method:
int number = list[zufall.Next(0, list.Count)];
https://msdn.microsoft.com/en-us/library/2dx6wyd4(v=vs.110).aspx
The Next(Int32, Int32) overload returns random integers that range
from minValue to maxValue – 1
I want to find how many values, in an array, are in sequence without sorting.
For Instance, if I have.
int[] arr = new int[] { 0, 1, 2, 3, 4, 5, 6, 9 } //0, 1, 2, 3, 4, 5, 6 are in sequence
int value = HighestSequence(arr);
//value prints 7
int[] arr = new int[] { 0, 4, 1, 2, 3, 4, 7, 9 } //1, 2, 3, 4 are in sequence
int value = HighestSequence(arr);
//value prints 4
int[] arr = new int[] { 0, 1, 2 } //0, 1, 2 is in sequence
int value = HighestSequence(arr);
//value prints 3
You don't specify what should happen if there is more than one subsequence in order, but I've assumed there will be only one.
Try this:
int length = 1;
int[] arr = new int[] { 0, 1, 2, 3, 4, 5, 6, 9 }; //0, 1, 2, 3, 4, 5, 6 are in sequence
//value prints 7
List<int> temp = arr.Zip(arr.Skip(1), (i1, i2) => length += (i2 - i1 == 1 ? 1 : 0)).ToList();
Length will contain the number of integers in sequence where arr[n] == arr[n+1] - 1
Cheers
EDIT:
In the case where there is more than one subsequence that is ordered such that arr[n] == arr[n+1] - 1, we'd need to decide how to handle it.
One way would be to reset the length when we find a value that doesn't meet the criteria:
arr = new int[] { 0, 1, 2, 5, 4, 5, 6, 9 }; //Possible bug ?
length = 1;
temp = arr.Zip(arr.Skip(1), (i1, i2) =>
{
if(i2 - i1 == 1)
{
length++;
}
else
{
length = 1;
}
return i1;
}).ToList();
But then this will not consider the "longest" subsequence, it will return the length of the "last" subsequence in the sequence.
The OP should specify what action he wants in such cases.
EDIT #2:
If we want to have the longest subsequence, then this could be used:
arr = new int[] { 0, 1, 2, 3, 4, 5, 6, 7, 5, 4, 5, 6, 7, 9 }; //Possible bug ?
length = 1;
int longest = length;
temp = arr.Zip(arr.Skip(1), (i1, i2) =>
{
if (i2 - i1 == 1)
{
if (++length > longest)
longest = length;
}
else
{
length = 1;
}
return i1;
}).ToList();
Caching the longest ordered subsequence length. Then use longest instead of length as the result.
EDIT #3:
Edits #1 & 2 should now contain the appropriate solution. I was obviously trying to come up with a solution to a comment from a user too quickly and I didn't realize that the current code in my VS solution was different than the code I posted here.
It is to be mentioned that the OP didn't have those additional constraints, and that I did mention right from the get go that my solution didn't address those additional constraints.
Nonetheless, it was an interesting problem to solve ;-)
Cheers
Try this out. I got the results of (7,4,3). Although Peter is correct about StackOverflow you should give your attempt and say your issue not just ask for an answer. I only provided it because it was a neat challenge.
var set1 = new [] { 0, 1, 2, 3, 4, 5, 6, 9 };
var result1 = HighestSequence(set1);
var set2 = new[] { 0, 4, 1, 2, 3, 4, 7, 9 };
var result2 = HighestSequence(set2);
var set3 = new [] { 0, 1, 2 };
var result3 = HighestSequence(set3);
public int HighestSequence(int[] values)
{
IList<int> sequenceCounts = new List<int>();
var currentSequence = 0;
for (var i = 0; i < values.Length; i++)
{
if (i == (values.Length - 1)) //End edge case
{
if (values[i] - values[i - 1] == 1)
{
currentSequence++;
sequenceCounts.Add(currentSequence);
}
}
else if ((values[i] + 1) == values[i + 1])
{
currentSequence++;
}
else
{
currentSequence++;
sequenceCounts.Add(currentSequence);
currentSequence = 0;
continue;
}
sequenceCounts.Add(currentSequence);
}
return sequenceCounts.Max();
}
Let's say I have a list of predefined numbers, and a list of predefined max limits.
When a user picks a limit, I need to randomly pick a certain amount of numbers from the first list, up until their totals match (As close to, but never over) the user selected total.
What I've tried so far:
void Main()
{
List<int> num = new List<int>(){ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, 20 };
int maxNum = 17;
List<int> curNum = new List<int>();
int curTotal = 0;
foreach(int sel in num.Where(x => x < maxNum)){
curTotal += sel;
if(curTotal <= maxNum){
curNum.Add(sel);
}
}
}
There needs to be x amount of numbers picked. In this case, 5 numbers picked, +- 20 numbers to be randomly picked from, and 1 max values.
So the end list should look like this:
1, 2, 3, 4, 7 (17)
1, 2, 3, 5, 6 (17)
1, 2, 3, 4, 6 (16) <- This will be fine if there isn't a solution to the max value.
Building upon #AlexiLevenkov's answer:
class Program
{
static void Main(string[] args)
{
int limit = 17;
int listSize = 5;
List<int> a = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 };
a.Shuffle();
List<int> genList = new List<int>();
int stoppedCount = 0;
for (int i = 0; i < a.Count(); i++)
{
if (i < listSize)
{
genList.Add(a[i]);
stoppedCount = i;
}
else
{
break;
}
}
while (genList.Sum() > limit)
{
genList.Remove(genList.Max());
stoppedCount++;
genList.Add(a[stoppedCount]);
}
}
}
static class ThisClass
{
public static void Shuffle<T>(this IList<T> list)
{
Random rng = new Random();
int n = list.Count;
while (n > 1)
{
n--;
int k = rng.Next(n + 1);
T value = list[k];
list[k] = list[n];
list[n] = value;
}
}
}
I think shuffle + "take while sum < limit" may be what you are looking for.
Something like following:
var shuffledList = num.ToList();
shuffledList.Shuffle();
var sum = 0;
var count = 0;
while (shuffledList[count] + sum < max)
{
sum += shuffledList[count++];
}
return shuffledList.Take(count);
I am not C# expert, and total LINQ beginner, having searched a bit in SO and Google without discovering how to do the following:
If I have, say, int[10,10] array, how can I get a 2D slice from it?
For example, if the values in the said array were dependent on their position (a[2,3] = 23, a[4,8] = 48, etc.), I'd like to perform the following pseudocode:
int[3,3] a_slice = slicer_method(a, 3, 6, 2, 5) // or anything equivalent to this
> [[ 32, 33, 34],
[ 42, 43, 44],
[ 52, 53, 54]]
It doesn't have specifically to use LINQ, but I've seen LINQ used in every similar operation I've come across lately.
#JaredPar is correct, there is no intrinsic way to do slices - that said, you can craft up an extension method to do so:
public static class Ext
{
public static T[] Slice<T>(this T[] source, int fromIdx, int toIdx)
{
T[] ret = new T[toIdx - fromIdx + 1];
for(int srcIdx=fromIdx, dstIdx = 0; srcIdx <= toIdx; srcIdx++)
{
ret[dstIdx++] = source[srcIdx];
}
return ret;
}
public static T[,] Slice<T>(this T[,] source, int fromIdxRank0, int toIdxRank0, int fromIdxRank1, int toIdxRank1)
{
T[,] ret = new T[toIdxRank0 - fromIdxRank0 + 1, toIdxRank1 - fromIdxRank1 + 1];
for(int srcIdxRank0=fromIdxRank0, dstIdxRank0 = 0; srcIdxRank0 <= toIdxRank0; srcIdxRank0++, dstIdxRank0++)
{
for(int srcIdxRank1=fromIdxRank1, dstIdxRank1 = 0; srcIdxRank1 <= toIdxRank1; srcIdxRank1++, dstIdxRank1++)
{
ret[dstIdxRank0, dstIdxRank1] = source[srcIdxRank0, srcIdxRank1];
}
}
return ret;
}
}
And a test:
void Main()
{
var singleArr = new int[]{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
singleArr.Slice(2, 4).Dump();
var doubleArr = new int[,]
{
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 },
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 },
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 },
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 },
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 },
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 },
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 },
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 },
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 },
};
doubleArr.Slice(2, 4, 2, 4).Dump();
}
There is no way to do this on the CLR because it doesn't support the notion of array slices. They best you can do is create a wrapper type over arrays that simulates slices
You can try something like this:
public T[,] Slice<T>(T[,] a, int x1, int y1, int x2, int y2)
{
var result = new T[x2 - x1, y2 - y1];
for (var i = x1; i < x2; i++)
{
for (var j = y1; j < y2; j++)
{
result[i - x1, j - y1] = a[i,j];
}
}
return result;
}
sample
public class MyArraySlice<T> where T:struct {
public MyArraySlice(T[,] array, int xMin, int xMax, int yMin, int yMax) {
Array = array;
XMin = xMin; XMax = xMax;
YMin = yMin; YMax = yMax;
}
public T this[int i, int j] { get {
if (XMin <= i && i < XMax && YMin <= j && j < YMax)
return Array[i+XMin, j+YMin];
throw new ArgumentOutOfRangeException();
}
}
T[,] Array;
int XMin;
int XMax;
int YMin;
int YMax;
}