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.
• It is guaranteed that you can produce a valid time from the given string.

## Solution 1: Brute Force

Enumerate all possible clock in reverse order and find the first matching one.

Time complexity: O(1)
Space complexity: O(1)

## Solution 2: Rules

Using rules, fill from left to right.

Time complexity: O(1)
Space complexity: O(1)

## C++

If you like my articles / videos, donations are welcome.

Buy anything from Amazon to support our website

Paypal
Venmo
huahualeetcode