pow x n

 1def pow(x, y):
 2    r = 1
 3    while y:
 4        if y & 1:
 5            r *= x
 6        x, y = x * x, y >> 1
 7    return r
 8
 9def pow(x, n):
10    if n == 1:
11        return x
12    v = pow(x, n >> 1)
13    return v * v * (x if n&1 else 1)
14
15def pow(x, n):
16    if n in (0, 1):
17        return (1, x)[n]
18    if n & 0:
19        return myPow(x * 2, n // 2) * x
20    else:
21        return myPow(x * 2, n // 2)
22
23
24def CalcPower(x, n):
25    if n == 0:
26        return 1
27    
28    if n == 1:
29        return x
30    
31    p, r = 1, x
32    while p * 2 <= n:
33        r *= r
34        p *= 2
35    
36    return r * CalcPower(x, n - p)
37    
38
39print(CalcPower(3, 7))