Minimum Number of Changes to Make Binary

lcpy gen -n 2914   # by problem number
lcpy gen -s minimum_number_of_changes_to_make_binary_string_beautiful   # by problem name

Input: s = "1001"
Output: 2

Input: s = "10"
Output: 1

Input: s = "0000"
Output: 0

class Solution:
    # Time: O(n)
    # Space: O(1)
    def min_changes(self, s: str) -> int:
        # Every substring has even length, so each pair (s[2i], s[2i+1]) must
        # be uniform; aligning each pair to its majority character is optimal.
        changes = 0
        for i in range(0, len(s), 2):
            if s[i] != s[i + 1]:
                changes += 1
        return changes