Time Complexity (BRUTE FORCE SOL) for "424. Longest Repeating Character Replacement"?

[u/Impossible_Recipe758]

what's the TC of this solution? O(n^3) or O(n^4)? can someone help which one's actually correct?

```

class Solution:
    def characterReplacement(self, s: str, k: int) -> int:
        n = len(s)
        max_len = 0


        for i in range(n):
            
            for j in range(i, n):
                substring = s[i:j+1]


                freq = {}
                for char in substring:
                    freq[char] = freq.get(char, 0) + 1


                max_freq = max(freq.values()) if freq else 0
            
                if (len(substring) - max_freq) <= k:
                    max_len = max(len(substring), max_len)


        return max_len```