A common application for recursion

A common application for recursion

• GregUzelac

  Probably he'll fire me out.
  
  

• Daniel Bogdan

  No, it's not. Plz help
  
  

• Fang Wang - MSFT

  give him my name. . . I am always looking for work. . . I also know how to google

  permutation +recursion +algorithm

  
  
  

• Anonymous1980

  Here is the class. A eral world example searcher for all records with the name "John Pat Doe" and you want to ensure that you get all of the records regardless how the name is in the record.

  public class Permutation : IDisposable

  {

  private int[] data = null;

  private int order = 0;

  private Permutation(int y)

  {

  this.data = new int;

  for (int x = 0; x < y; ++x)

  {

  this.data[x] = x;

  }

  this.order = y;

  }

  public Permutation()

  {

  }

  public static object[] Permutate(string arg, string delimiter)

  {

  string result = string.Empty;

  string[] s;

  object[] res;

  string ss;

  System.Collections.ArrayList list = new System.Collections.ArrayList();

  s = (arg).Split(delimiter.ToCharArray());

  if (s.Length == 1)

  {

  list.Add(s[0]);

  }

  else

  {

  res = new object[s.Length];

  Permutation perm = new Permutation(s.Length);

  while (perm != null)

  {

  res = perm.ApplyTo(s);

  ss = string.Empty;

  for (int x = 0; x < s.Length; x++)

  {

  ss += res[x].ToString() + delimiter;

  }

  list.Add(ss.TrimEnd(delimiter.ToCharArray()));

  perm = perm.Successor();

  }

  }

  return list.ToArray();

  }

  private object[] ApplyTo(object[] arr)

  {

  if (arr.Length != this.order)

  return null;

  object[] result = new object[arr.Length];

  for (int i = 0; i < result.Length; ++i)

  {

  result[x] = arr[this.data[x]];

  }

  return result;

  } // ApplyTo()

  private Permutation Successor()

  {

  Permutation result = new Permutation(this.order);

  int left, right;

  for (int k = 0; k < result.order; ++k) // Step #0 - copy current data into result

  {

  result.data[k] = this.data[k];

  }

  left = result.order - 2; // Step #1 - Find left value

  while ((result.data[left] > result.data[left+1]) && (left >= 1))

  {

  --left;

  }

  if ((left == 0) && (this.data[left] > this.data[left+1]))

  return null;

  right = result.order - 1; // Step #2 - find right; first value > left

  while (result.data[left] > result.data[right])

  {

  --right;

  }

  int temp = result.data[left]; // Step #3 - swap [left] and [right]

  result.data[left] = result.data[right];

  result.data[right] = temp;

  int x = left + 1; // Step #4 - order the tail

  int j = result.order - 1;

  while (i < j)

  {

  temp = result.data[x];

  result.data[x++] = result.data[j];

  result.data[j--] = temp;

  }

  return result;

  } // Successor()

  #region IDisposable Members

  public void Dispose()

  {

  // TODO: Add Permutation.Dispose implementation

  }

  #endregion

  } // class Permutation

  
  

• skylar119506

  is this a homework assignment
  
  

• shuttler

  My project manager gave me this. He told me to create a c# function for that and after it has to implement it in a real world. But no idea about the real world right now. Can u help me
  
  

• haiaw

  Hmm...looks a lot like an assignment I was given back when I was in College.

  Perhaps if you can tell us more about the 'real world' problem that you are trying to apply this to, we can give you some help.

  
  
  
• A common application for recursion