算法分析与设计第十四周：424. Longest Repeating Character Replacement

class Solution(object):    def characterReplacement(self, s, k):        if s == "":            return 0        char = [0 for _ in range(26)]        i, j = 0, 0        maxCnt = 1        for c in s:            num = ord(c) - ord('A')            char[num] = 1 if char[num] == 0 else char[num] + 1            maxCnt = max(char)            if j - i + 1 - maxCnt > k:                char[ord(s[i]) - ord('A')] -= 1                i += 1            j += 1        return j - i