uniq_substr.py

# python 2+
from itertools import takewhile, ifilter, izip, tee, starmap, chain

def uniq_substrings(origin):
    suffixes = chain([""], sorted(tails(origin)))
    return sum(starmap(suffix, pairwise(suffixes)))

def pairwise(iterable):
    a, b = tee(iterable)
    next(b, None)
    return izip(a, b)

def common_prefix(pre, post):
    return takewhile(lambda (k1, k2): k1==k2, izip(pre, post))

def suffix(pre, post): 
    return len(post) - ilen(common_prefix(pre, post))

def tails(origin): 
    return (origin[i:] for i in xrange(ilen(origin)))

def ilen(iterable): 
    return sum(1 for it in iterable)