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By: a guest on Jun 13th, 2012  |  syntax: None  |  size: 1.82 KB  |  hits: 15  |  expires: Never
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  1. Can anyone help me check this python code? [closed]
  2. def permutation(Ori, Curr, used):
  3.   if len(Ori) == len(Curr):
  4.       #print Curr
  5.       return
  6.  
  7.   for i in xrange(len(Ori)):
  8.       if used[i]:
  9.           continue
  10.       used[i] = True
  11.       Curr.append(Ori[i])
  12.       print Curr,i," after append"
  13.       permutation(Ori, Curr, used)    # further level
  14.       used[i] = False
  15.       print Curr,i," before delete"
  16.       Curr = Curr[0:-1]               # Curr.pop() works
  17.       print Curr,i," after delete"
  18.   return
  19.  
  20. if __name__ == "__main__":
  21.   used = [False]*3
  22.   Curr = []
  23.   permutation([1,2,3], Curr, used)
  24.        
  25. [1] 0  after append
  26. [1, 2] 1  after append
  27. [1, 2, 3] 2  after append
  28. [1, 2, 3] 2  before delete
  29. [1, 2] 2  after delete     <------
  30. [1, 2, 3] 1  before delete <------
  31. [1, 2] 1  after delete
  32. [1, 2, 3] 2  after append
  33. [1, 2, 3] 2  before delete
  34. [1, 2] 2  after delete
  35. [1, 2, 3] 0  before delete
  36. [1, 2] 0  after delete
  37. [1, 2, 2] 1  after append
  38. [1, 2, 2] 1  before delete
  39. [1, 2] 1  after delete
  40. [1, 2, 3] 2  after append
  41. [1, 2, 3] 2  before delete
  42. [1, 2] 2  after delete
  43.        
  44. def f(A):
  45.      if(len(A) == 10):
  46.          return
  47.      A.append('a')
  48.      f(A)
  49.      print A
  50.  #   A = A[0:-1]                            
  51.  #   A.pop()
  52.      return
  53.  
  54.  if __name__ == "__main__":
  55.     f([])
  56.        
  57. permutation(Ori, Curr, used)    # further level
  58.        
  59. permutation(Ori, Curr[:], used)    # further level
  60.        
  61. Curr.append(Ori[i])
  62.        
  63. Curr = Curr + [Ori[i]]
  64.        
  65. def permutations(iter):
  66.     """
  67.         >>> print(list( permutations(range(3)) ))
  68.         [[0, 1, 2], [0, 2, 1], [1, 0, 2], [1, 2, 0], [2, 0, 1], [2, 1, 0]]
  69.     """
  70.     elements = list(iter)
  71.  
  72.     # base case
  73.     if len(elements)==0:
  74.         yield []
  75.  
  76.     for i,elem in enumerate(elements):
  77.         withoutElem = elements[:i]+elements[i+1:]
  78.         for perm in permutations(withoutElem):
  79.             yield [elem]+perm
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