Question

I have a list:

a = [2, 3, 5, 6, 6, 7, 10, 11, 13, 14, 15, 16, 16, 17, 18, 20, 21]

Is it possible to make a function that shows the longest list of distinct, consecutive elements?

Please, show how to do it

In this case the answer should be:

13, 14, 15, 16, 17, 18

Answer 1

The simplest thing to do seems to be to loop through the list once, building any sequences you can find and then print the longest one.

a = [2, 3, 5, 6, 6, 7, 10, 11, 13, 14, 15, 16, 16, 17, 18, 20, 21]

seqlist = [] # List of Sequences
seq = []     # Current Sequence
last = -1

for item in a:
   # Start a new sequence if the gap from the last item is too big
   if item - last > 1:
       seqlist.append(seq)
       seq = []

   # only add item to the sequence if it's not the same as the last
   if item != last:
        seq.append(item)

   last = item

# Print longest sequence found
print max(seqlist)