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  1. def make_palindrome(s):
  2.     char_count = Counter(s)
  3.     flag = 0
  4.     mid = (None, None)
  5.  
  6.     for key, count in char_count.items():
  7.         if count % 2 != 0:
  8.             if flag == 0:
  9.                 flag = 1
  10.                 mid = (key, count % 2)
  11.                 char_count[key] = count - count % 2
  12.             else:
  13.                 return 'Impossible'
  14.  
  15.     sorted_list = sorted(char_count.keys())
  16.  
  17.     palindrome = []
  18.  
  19.     for el in sorted_list:
  20.         palindrome.append(el*(char_count[el]//2))
  21.  
  22.     if mid[0]:
  23.         palindrome.append(mid[0]*mid[1])
  24.  
  25.     for i in range(len(sorted_list) - 1, -1, -1):
  26.         palindrome.append(sorted_list[i]*(char_count[sorted_list[i]]//2))
  27.  
  28.     return ''.join(palindrome)
  29.  
  30.  
  31. s = input()
  32.  
  33. print(make_palindrome(s))
Runtime error #stdin #stdout #stderr 0.12s 23528KB
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stdin
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Standard input is empty
stdout
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Standard output is empty
stderr
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Traceback (most recent call last):
  File "./prog.py", line 31, in <module>
EOFError: EOF when reading a line
https://ideone.com/sh83Zh
language:
Python 3 (python  3.9.5)
created:
4 years ago
visibility:
public

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