Number of Valid Clock Times


In this Python code, ans
is initially set to 1. If the last character of the time
string is ‘?’, ans
is multiplied by 10. If the second last character is ‘?’, ans
is multiplied by 6. These steps consider all possible minute combinations.
Next, it checks for hour combinations. If both hour characters are ‘?’, ans
is multiplied by 24. Otherwise, if the first hour character is ‘?’, ans
is multiplied by 3 if the second character is less than ‘4’, otherwise ans
is multiplied by 2. If the second hour character is ‘?’, ans
is multiplied by 4 if the first character is ‘2’, otherwise ans
is multiplied by 10.
Finally, it returns ans
, which is the total number of possible valid times.