lab three solution | Python Fiddle

# collatzify: int -> int
# transform a number via the rules of the collatz sequence
def collatzify(n):
   return n/2 if n % 2 == 0 else 3*n + 1

# collatzSequence: int -> [int]
# generate the collatz sequence starting at the given number
def collatzSequence(number):
   seqSoFar = [number]

while number > 1:
      number = collatzify(number)
      seqSoFar.append(number)

return seqSoFar

# frequency: int, [int] -> int
# count the number of occurences of a number in a list
def frequency(soughtNumber, numberList):
   counter = 0

for x in numberList:
      if x == soughtNumber:
         counter = counter + 1

return counter
        
        
# histogram: [int] -> [int]
# compute the histogram of a given list
def histogram(numberList):
   # return a list of frequency counts from 0 to max(numberList)

highest = max(numberList)
   current = 0
   theHistogram = []

while current <= highest:
      theHistogram.append(frequency(current, numberList))
      current = current + 1

return theHistogram

# collatzHistogram: int -> [int]
# compute a histogram of the lengths of all collatz sequences
# starting at 1 and going to the input number (inclusive).
def collatzHistogram(numberOfNumbers):
   collatzLengths = []

for n in range(1, numberOfNumbers+1):
      collatzLengths.append(len(collatzSequence(n)))

return histogram(collatzLengths)

# printHist: [int] -> None
# print out a histogram to the terminal
def printHist(aHistogram):
   theMax = max(aHistogram)
    
   for i, count in enumerate(aHistogram):
      print ("%s: " % i) + "#" * int(round(100.0 * count / theMax))

''' These tests won't run in Pythonfiddle, but here they are anyway
if __name__ == "__main__":
   from unittest import test

test(8, collatzify(16))
   test(14, collatzify(28))
   test(10, collatzify(3))

test([1], collatzSequence(1))
   test([5,16,8,4,2,1], collatzSequence(5))
   test([7, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1], collatzSequence(7))

test(0, frequency(5,[1,2,3,4]))
   test(1, frequency(3,[1,2,3,4]))
   test(5, frequency(6,[1,6,6,6,6,7,6]))

test([1,1,1,1,1,1,1,1,1,1], histogram(range(10)))
   test([1,2,2,0,1,0,1,3,1,1,0,0,0,0,0,0,0,0,0,1], histogram([6,4,2,8,7,7,9,0,1,1,2,7,19]))
   test([0]*25 + [1], histogram([25]))

test([0,1,1], collatzHistogram(2))
   test([0,1,1,1,0,0,1,0,1], collatzHistogram(5))
   test([0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1], collatzHistogram(10))
'''

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