C# String permutation

Question

I have 5 strings, such as: \"one\", \"two\", \"three\", \"four\", and \"five\". I need to get all permutations of these strings. I\'ve explored all internet resources, but a

Answer 1

Here's a class that works in .Net 2.0. First, sort your array. Then use it by looping over while(Permute.Next(array)). When there are no more permutations, Permute.Next returns false.

using System;
using System.Collections.Generic;
using System.Text;

public class Permute
{
    public static bool Next(IList list)
    {
        int k = FindSmallestK(list);
        if (k < 0) return false;
        int l = FindLargestL(list, k);
        Swap(list, k, l);
        Reverse(list, k + 1);
        return true;
    }

    private static void Reverse(IList list, int p)
    {
        for (int i = p, j = list.Count - 1; i < j; i++, j--)
        {
            Swap(list, i, j);
        }
    }

    private static void Swap(IList list, int k, int l)
    {
        IComparable temp = list[k];
        list[k] = list[l];
        list[l] = temp;
    }

    private static int FindLargestL(IList list, int k)
    {
        for (int i = list.Count - 1; i > k; i--)
        {
            if (list[k].CompareTo(list[i]) < 0) return i;
        }
        return -1;
    }

    private static int FindSmallestK(IList list)
    {
        for (int i = 0; i < list.Count - 1; i++)
        {
            if (list[i].CompareTo(list[i + 1]) < 0) return i;
        }
        return -1;
    }
}