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Missing number -n to n [closed]

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There is a number N (i.e., N = 3).
I create an array from -N to N (i.e. {-3, -2, -1, 0, 1, 2, 3})
I randomly remove a number from the array (i.e. {-3, -2, 0, 1, 2, 3}, removed -1)
I shuffle the Array (i.e. {-2, 0, 2, 3, -3, 1})
Write a function
public int FindMissing(int[] arr)
That takes the shuffled Array from the initial steps and identifies and returns the array's missing number.
I've done it like this, but I think I did it wrong:
public partial class findMissingNumber
{
public static int FindMissing(int[] arr, int N)
{
int summ = (N - 1) * N / 2;
int sumarr = 1;
for (int i = 1; i < arr.Length; i++)
{
sumarr += arr[i];
}
return summ - sumarr;
}
public static void Main()
{
Console.WriteLine(FindMissing(new int[] { -2, 0, 2, 3, -3, 1 }, 3));
Console.ReadLine();
}
}

The sum of all the numbers in an array [-N, N] is 0.
If an element is missing it'll be 0 minus the missing number.
If 1 is missing, sum = 0 - 1, therefore the missing number is -sum. Except when 0 is missing.
With LINQ is very easy:
using System.Linq;
class findMissingNumber
{
public static int FindMissing(int[] arr)
{
return (arr.Contains(0)) ? -arr.Sum() : 0;
}
public static void Main()
{
Console.WriteLine(FindMissing(new int[] { -2, 2, 1, 3, -3, -1 }));
}
}
Of course if you know that the array will always miss a number you don't even need to check if 0 is missing and it all boils down to -arr.Sum()
Without LINQ is a little longer, but works in the same way:
public static int FindMissing(int[] arr)
{
int sum = 0;
if (Array.FindIndex(arr, x => x == 0) < 0)
return 0;
Array.ForEach(arr, x => sum += x);
return -sum;
}
Again, if you know that an element will alwas be missing, you can avoid looking for zero
I used lambdas, but you can write your predicate as you like https://zetcode.com/csharp/predicate/

How to replace the contents of an integer array with the index value at each index? [closed]

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How do I replace the contents of an array of integers so that the value at each index is the index itself?
This is what I have tried so far:
var result = array;
for(int i = 0; i < array.Length; i++)
{
array.IndexOf(i);
Console.WriteLine(array.IndexOf(i));
}
return result;
Given an input array (0, 0 ,0), I am getting the following console output: 0 -1 -1. And the array output contents are (0, 0, 0) instead of (0, 1, 2).

your question is a bit confusing. But if you mean how to assign the index value to the arrays elements you could do this.
var result = array;
for(int i = 0; i < array.Length; i++)
{
array[i] = i;
Console.WriteLine(array.IndexOf(i));
}
return result;
The result will then be 0,1,2
Hope this helps.

I think the following code should help.
int[] myIntArray = new int[5] { 1, 2, 3, 4, 5 };
for(int i = 0; i < myIntArray.Length; i++)
{
myIntArray[i] = i;
Console.WriteLine(myIntArray[i]);
}
correct me if i am wrong.

List items calculation [closed]

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Let's say I have a list / array of integers, i.e:
{1, 2, 3, 4}
Is there a way to get every single possible combination of additions and add them to another list / array?
Like this:
1+2, 1+3, 1+4,
2+3, 2+4,
3+4,
1+2+3, 1+2+4, 1+3+4,
2+3+4,
1+2+3+4
So the end-result would be (without duplicates):
{3, 4, 5, 6, 7, 8, 9, 10}

With more specific to int list you can do that
static List<int> GetCombination(List<int> list, List<int> combinations, int sumNum, bool addNumberToResult = false)
{
if (list.Count == 0) {
return combinations;
}
int tmp;
for (int i = 0; i <= list.Count - 1; i++) {
tmp = sumNum + list[i];
if(addNumberToResult){
combinations.Add(tmp);
}
List<int> tmp_list = new List<int>(list);
tmp_list.RemoveAt(i);
GetCombination(tmp_list,combinations,tmp, true);
}
return combinations;
}
and to call it simply do
List<int> numbers = new List<int>(){1,2,3,4,5};
List<int> possibleCombination = GetCombination(numbers, new List<int>(), 0);
and to remove duplicate
possibleCombination.Distinct()
If you want it orderer you can call
possibleCombination.Distinct().OrderBy(itm => itm)
or
possibleCombination.Distinct().OrderByDescending(itm => itm)
C# fiddle
Edit : As Pierre rightly pointed out, the code did not stick to the question, I corrected accordingly, adding an parameters for adding or not the numbers to the result list.

Based on this great answer here is a version that will allow you to eliminate the "small subset"(*)
public static List<List<T>> GetCombination<T>(List<T> inputList, int minimumItems = 1)
{
int count = (int)Math.Pow(2, inputList.Count) - 1;
List<List<T>> result = new List<List<T>>(count + 1);
if (minimumItems == 0)
result.Add(new List<T>());
for (int i = 1; i <= count; i++)
{
List<T> combinason = new List<T>(inputList.Count);
for (int j = 0; j < inputList.Count; j++)
{
if ((i >> j & 1) == 1)
combinason.Add(inputList[j]);
}
if (combinason.Count >= minimumItems)
result.Add(combinason);
}
return result;
}
Result:
>> { {1,2}, {1,3}, {2,3}, {1,2,3}, {1,4}, {2,4},
>> {1,2,4}, {3,4}, {1,3,4}, {2,3,4}, {1,2,3,4} }
From here a simple .Sum() on the subset:
Subsets.ForEach( s => result.Add(s.Sum()) );
As you wanted to clear every duplicate in the list:
DoublonList.Distinct();
C# fiddle
ps: (*) Can't find the word in english for groupe of only one element

Finding the highest pair in int array [closed]

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I have a dice game, where I need to find the highest pair of 5 dices and get the total of it.
I have made this code so far which counts the numbers into pairs. Now I want to find the highest pair.
Code:
int Pair[];
Pair = new int[7] {0, 0, 0, 0, 0, 0, 0} //Seven pairs because i dont want to use Pair[0]
int TT[];
TT = new int[5] { 1, 6, 3, 1, 3 }; //five dice
int t = 1;
for(int i = 0; i < 5; i++)
{
if ( TT[i] == t)
{
Pair[t] = Pair[t] + 1;
t = t + 1;
}
}

If I understand your problem correctly, I think you are overcomplicating it. If you think about it, what you want are the two highest numbers from an arry. Simply sort it, and reverse it, and take the two first numbers.
class Program
{
static void Main(string[] args)
{
int[] Dice = new int[5] { 1, 6, 3, 1, 3 };
Array.Sort(Dice);
Array.Reverse(Dice);
Console.WriteLine("The largest pair is ({0}, {1})", Dice[0], Dice[1]);
}
}
The other possibility for the largets pair (as mentioned in a comment) is that you want to find the highest number in the list that occurs twice. You can do this by sorting the Array, reversing it, so you read from the highest number. Then incrementally check if the current number matches the next number, and if this is the case, you found the highest pair.
class Program
{
static void Main(string[] args)
{
int[] Dice = new int[5] { 1, 6, 3, 1, 3 };
Array.Sort(Dice);
Array.Reverse(Dice);
for (int i = 1; i < Dice.Length; i++)
{
if (Dice[i] == Dice[i - 1])
{
Console.WriteLine("The largest pair is ({0}, {1})", Dice[i], Dice[i-1]);
break;
}
}
}
}

Convert string to char error message [closed]

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Closed 9 years ago.
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Cannot convert string to char error message. I am trying to be able to write a program that will, for example, allow the user to input 1800HIETHC and it will give them back all digits.
I am already stuck.... Any help or advise on what to do?
static void Main(string[] args)
{
char number = ' ';
int numb = 0;
Console.WriteLine("Please enter the telephone number...");
number = Console.ReadLine();
while (number <= 10)
{
if (number == 'A')
{
numb = 2;
}
}
Console.WriteLine(numb);
}
}
}

Console.ReadLine gives you a string
a string is, among other things, a collection of chars
try this
string number = "";
int numb = 0;
Console.WriteLine("Please enter the telephone number...");
number = Console.ReadLine();
for(int i=0; i<number.Count; i++)
{
if (number[i] == 'A')
{
//...
}
}

Console.ReadLine() returns a string not a character. So you cannot assign it to the variable number.
Once you have assigned it to a string you can get characters out of the string by doing myString[0]

If I understand you correctly,
string number = "1800HIETHC"; //Console.ReadLine() reads whole line, not a single char.
int[] nums = Digits(number);
static int[] Digits(string number)
{
return number.Where(char.IsLetterOrDigit).Select(ToNum).ToArray();
}
static int ToNum(char c)
{
int[] nums = { 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 9, 9, 9, 9 };
if (char.IsDigit(c)) return c - '0';
c = char.ToUpper(c);
return nums[c - 'A'];
}