python def max_consecutive_char(s: str) -> str: if not s: return ''

max_char = s[0]
max_count = 1
current_char = s[0]
current_count = 1

for i in range(1, len(s)):
    if s[i] == current_char:
        current_count += 1
    else:
        if current_count > max_count:
            max_count = current_count
            max_char = current_char
        current_char = s[i]
        current_count = 1

# Check for the last sequence of characters
if current_count > max_count:
    max_count = current_count
    max_char = current_char

return max_char

Example usage

print(max_consecutive_char('aabbbccddddde')) # Will output 'd'

The function iterates through the string once, tracking the current character and the length of its sequence. When the sequence is interrupted, it compares the length with the maximum and updates the result if necessary. At the end, it returns the character with the maximum consecutive repetitions.