Detect whether sequence is a multiple of a subsequence in Python

Question

I have a tuple of zeros and ones, for instance:

(1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1)

It turns out:

(1, 0, 1, 1, 1, 0, 1, 1, 1,          


        

Answer 1

Simplifying Knoothe's solution. His algorithm is right, but his implementation is too complex. This implementation is also O(n).

Since your array is only composed of ones and zeros, what I do is use existing str.find implementation (Bayer Moore) to implement Knoothe's idea. It's suprisingly simpler and amazingly faster at runtime.

def f(s):
    s2 = ''.join(map(str, s))
    return s[:(s2+s2).index(s2, 1)]