计数相同字符的最大子串

def max_equal_substring(s):
    max_len = 0
    start = 0
    for end in range(len(s)):
        if end > 0 and s[end] != s[end - 1]:
            start = end
        max_len = max(max_len, end - start + 1)
    return max_len

# 示例
s = "aaabbbccc"
print(max_equal_substring(s))  # 输出: 3

def max_equal_substring_hash(s):
    char_index = {}
    max_len = 0
    start = 0
    for end, char in enumerate(s):
        if char in char_index and char_index[char] >= start:
            start = char_index[char] + 1
        char_index[char] = end
        max_len = max(max_len, end - start + 1)
    return max_len

# 示例
s = "aaabbbccc"
print(max_equal_substring_hash(s))  # 输出: 3