You are given a string time in the form of hh:mm, where
some of the digits in the string are hidden (represented by ?).
The valid times are those inclusively between 00:00 and
23:59.
Return the latest valid time you can get from time by
replacing the hidden digits.
Example 1:
Input: time = "2?:?0" Output: "23:50" Explanation: The latest hour beginning with the digit '2' is 23 and the latest minute ending with the digit '0' is 50.
Example 2:
Input: time = "0?:3?" Output: "09:39"
Example 3:
Input: time = "1?:22" Output: "19:22"
Constraints:
time is in the format hh:mm.