Given a string s formed from zeros and ones, return the maximum score after splitting the string into two non-empty substrings (left and right).
The score after splitting a string is the number of zeros in the left substring plus the number of ones in the right substring.
max_score("00111") ➞ 5
# left = "00", right = "111" ➞ 2 + 3 ➞ 5
max_score("1111") ➞ 3
max_score("01001") ➞ 4
max_score("010101010101010101") ➞ 10
N/A