# You have a music player that should be playing a 900 song list randomly.
  # You notice that you keep hearing a song being repeated during your drive and
  # you are curious if its truly random.
  
  from collections import Counter
  import random
  
  r             = random.Random() 
  songs         = range(1,900)
  unplayed      = set(songs)
  
  # You also keep hitting skip in the hopes a particular song comes up. 
  # Write a piece of code that simulates this.  You should tell me three things;
  # 1) the number of songs played before a repeat occurs
  # 2) how many songs needed to be played before you played them all
  # 3) after you succeed in playing them all, how many times has the most common song been played.
  
  counter         = Counter()
  firstrepeat     = None
  totalplays      = 0
  
  while unplayed:
      song = r.choice(songs)
      unplayed -= set([song])
      if firstrepeat is None and song in counter:
          firstrepeat = len(counter)
      counter[song] += 1
      totalplays += 1
  
  print(f"""
  Number of songs played before a repeat:             {firstrepeat}
  Total number songs played:                          {totalplays}
  Most common song:                                   {counter.most_common()[0][0]}
  How many times has the most common song was played: {counter.most_common()[0][1]}
  """)

  $ python3 foo.py

  Number of songs played before a repeat:             50
  Total number songs played:                          7263
  Most common song:                                   375
  How many times has the most common song was played: 17