slide_subarray

def get_len(a, b):
    if len(a) > len(b):
        a, b = b, a
    res = 0
    for i in range(-len(a) + 1, len(b)):
        cur = 0
        for j in range(len(a)):
            if 0 <= i + j < len(b) and a[j] == b[i + j]:
                cur += 1
                res = max(res, cur)
            else:
                cur = 0
    return res