Help me solve this math , algorithm problem. Really interest

Prime b

Prompt the user for amount of possible numbers, the user types the numbers and then the program needs to display all the possibilities of those numbers.

For example:

Program prompts the user for amount of numbers,
lets say user types 3
Then he user has to type 3 different numbers
Lets say user types 1,2,3
Now the program needs to show all possible numbers out of those 3 numbers
so it would be 1,2,3, 12,13,21,31,23,32, etc you get the general idea.

5 Replies

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Hemant Srivastava13y ago
Accepted answer
Basically in this problem, you need to generate firstly power set of those numbers and then for each element in its power set, you need to get all permutations of their digits of the element.

here is complete solution (Sample code is also attached..)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication3
{
class PermuteNPowerSet
{
public List GeneratePowerSet(List listOfNumbers)
{
//
var result = new List>();
for (int i = 0; i < (1 << listOfNumbers.Count); i++)
{
// 1 << n == the n-th power of 2
var sublist = new List();
for (int j = 0; j < listOfNumbers.Count; j++)
{
// analyze each bit in "i"
if ((i & (1 << j)) != 0)
{
// if the j-th bit of i is set...
sublist.Add(listOfNumbers[j]); // add the item to the current sublist
}
}
result.Add(sublist); // add the current sublist to the final result
}
List listofNums = new List();
foreach (List item in result)
{
int multiplier = 1;
int number = 0;
foreach (int digit in item)
{
int i = digit * multiplier;
number = number + i;
multiplier = multiplier * 10;
}
listofNums.Add(number);
}
return listofNums;
}
public void GeneratePermutations(string item)
{
char[] list = item.ToCharArray();
int x = list.Length - 1;
go(list, 0, x);
}
private void go(char[] list, int k, int m)
{
int i;
if (k == m)
{
Console.Write(list);
Console.WriteLine(" ");
}
else
{
for (i = k; i <= m; i++)
{
swap(ref list[k], ref list[i]);
go(list, k + 1, m);
swap(ref list[k], ref list[i]);
}
}
}
private void swap(ref char a, ref char b)
{
if (a == b) return;
a ^= b;
b ^= a;
a ^= b;
}
}
class Program
{
static void Main()
{
PermuteNPowerSet oPermuteNPowerSet = new PermuteNPowerSet();
var list = new List { 1, 2, 3 };
List powerSetNumbers = oPermuteNPowerSet.GeneratePowerSet(list);

/*calling to generate permutations*/
foreach (int i in powerSetNumbers)
{
oPermuteNPowerSet.GeneratePermutations(i.ToString());
}

Console.Read();
}
}
}
Prime b13y ago
You program GPS?
Also where did you get your degree?
And how much were your starting salary?
What languages do you know?
Hemant Srivastava13y ago
Glad to see you it worked for you! I am in USA and Software developer in Geocoding Technology.

Please mark it accepted so that others could refer to this.
Prime b13y ago
Hey thx a lot.
Where are you a software developer?
What do you develop?
D L13y ago
My solution would be to...

User types in 3 which becomes a new array length for an array of integers.

Then do a for loop:

for (int j = 0; j < arrayofNums.Length; j ++)
{
arrayofNums[j] = (input a number);

}

Once you have the arrayofNums filled with your numbers then you do permutations on it.

http://www.codeproject.com/Articles/37215/Permutations-in-C-Using-Recursion