Power Function (Fast Exponentiation)

Write a recursive function power(base, exponent) that computes base raised to the power exponent, where exponent is a non-negative integer.

A naive recursive multiplication (base * power(base, exponent - 1)) works but makes exponent recursive calls. Instead, use recursive fast exponentiation (divide and conquer):

• power(base, 0) = 1
• if exponent is even: power(base, exponent) = power(base, exponent / 2) ^ 2
• if exponent is odd: power(base, exponent) = power(base, exponent / 2) ^ 2 * base (using integer division for exponent / 2)

This reduces the number of recursive calls to O(log(exponent)).

Example: base = 2, exponent = 10 returns 1024.

The constraints are chosen so the true mathematical result always fits safely within a standard 64-bit/double-precision integer range.

-20 <= base <= 20, 0 <= exponent <= 12