Formatted question description: https://leetcode.ca/all/372.html
372 Super Pow Your task is to calculate: a^b mod 1337 where a is a positive integer and b is an extremely large positive integer given in the form of an array. Example 1: Input: a = 2, b =  Output: 8 Example 2: Input: a = 2, b = [1,0] Output: 1024
a^b % 1337 = (a%1337)^b % 1337 xy % 1337 = ((x%1337) * (y%1337)) % 1337
Reduced by half, the difference is that the remainder of 1337 is added. Since the given exponent b is a representation of a one-dimensional array, it must be very inconvenient to deal with it if we halve it.
So we use bitwise processing, such as
2^23 = (2^2)^10 * 2^3, so we can start from the highest bit of b, calculate a result and store it in res, and then go to the next bit , The tenth power of res is multiplied by the power of a and the remainder is 1337.