encode.py

def encode(combo, maxn):
    base_offset = 1
    s = 0
    last = maxn + 1
    for c in sorted(combo, reverse=True):
        s += c*base_offset
        base_offset *= last
        last = c + 1
    return s
    
def decode(n, num, maxn):
    last = maxn + 1
    r = []
    for _ in range(num):
        d = n % last
        n //= last
        last = d + 1
        r.append(d)
    return r