0159.Longest Substring with At Most Two Distinct Characters

from collections import Counter

class Solution:
    def lengthOfLongestSubstringTwoDistinct(self, s: str) -> int:
        cnt = Counter()
        ans = j = 0
        for i, c in enumerate(s):
            cnt[c] += 1
            while len(cnt) > 2:
                cnt[s[j]] -= 1
                if cnt[s[j]] == 0:
                    cnt.pop(s[j])
                j += 1
            ans = max(ans, i - j + 1)
        return ans

if __name__ == "__main__":
    sol = Solution()
    print(sol.lengthOfLongestSubstringTwoDistinct("eceba"))
    print(sol.lengthOfLongestSubstringTwoDistinct("ccaabbb"))