题解 | #最大值#

Python极简无需双指针，滑动窗口即可（因为固定了K）：

class Solution:
    def maxValue(self , s , k ):
        l = res = 0
        while l < len(s) and l+k <= len(s):  #判断不超过索引
            if int(s[l:l+k]) > int(res):
                res = s[l:l+k]
            l += 1
        return int(res)