def f(arr):
    return 0 if not arr else arr[0] + f(arr[2:])
print(f([3, 3, 3]))

g1 = (c * 2 for c in 'ABC')
def gen(m): 
    for c in m:
        yield c * 2
g2 = gen('ABC')
print(list(g1) == list(g2))

G = (с for с in '123')  
I1 = iter(G)  
I2 = iter(G)
_ = next(I1)
_ = next(I1)
print(next(I2))

def f(n):
    yield from range(n)
    yield from (x ** 2 for x in range(n))
res = ':'.join(str(i) for i in f(3))
print(res)

line = 'aaa bbb ccc d e f'
g1 = ''.join(x.upper() for x in line.split() if len(x) > 1)
def gen(line): 
    for x in line.split():
        if len (x) > 1:
            yield x.upper()
g2 = ''.join(gen(line))
print(g1 == g2)

def gen(n):
    for i in n:
        yield i
g = gen('abcd')
l = len(list(g))
print(next(g), l)

def f(a, b, c):
    return (a + 2*b) ** c
w = {"a": 1, "b": 2, "c": 3}
print(f(**w))

ranks = {'aaa': 1, 'bbbb': 2}
rank_dict = {rank: name for name, rank in ranks.items()}
set_len = {len(name) for name in rank_dict.values()}
print(rank_dict, set_len)

def f(seq):
    if not seq:  
        return [seq]
    else:
        res = []
        for i in range(len(seq)):
            rest = seq[:i] + seq[i+1:] 
            for x in f(rest):
                res.append(seq[i:i+1] + x)
        return res
a = f([1, 2])
b = f([1, 2, 3, 4, 5])
print(a, len(b))

x = [[0] for i in range(3)]
x[0].append(1)
print(x)