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You don't need a regex for this. To find first you can simply iterate through the line until you find a digit. To find second you can do the same but in reverse. This is more efficient than running...
Answer
#3: Post edited
by
matthewsnyder
·
2024-07-18T21:14:33Z (4 months ago)
You don't need a regex for this. To find `first` you can simply iterate through the line until you find a digit. To find `second` you do the same but in reverse. This is more efficient than running a regex.- For a problem as small as the example, it doesn't matter and arguably the regex adds readability. But I assume AoC makes you run this on a much bigger input as well.
- You also don't need to construct the calibration number as a string. `first*10 + second` gives the calibration number.
- When finding the digits, you can do a time-space tradeoff by creating a hashmap that maps each char 0-9 to the corresponding digit. Plugging the chars into this map is probably faster than parsing the string to an integer.
- You don't need a regex for this. To find `first` you can simply iterate through the line until you find a digit. To find `second` you can do the same but in reverse. This is more efficient than running a regex.
- For a problem as small as the example, it doesn't matter and arguably the regex adds readability. But I assume AoC makes you run this on a much bigger input as well.
- You also don't need to construct the calibration number as a string. `first*10 + second` gives the calibration number.
- When finding the digits, you can do a time-space tradeoff by creating a hashmap that maps each char 0-9 to the corresponding digit. Plugging the chars into this map is probably faster than parsing the string to an integer.
#2: Post edited
by
matthewsnyder
·
2024-07-18T21:14:19Z (4 months ago)
You don't need a regex for this. To find `first` you simply iterate through the line until you find a digit. To find `second` you do the same but in reverse. This is more efficient than running a regex.- For a problem as small as the example, it doesn't matter and arguably the regex adds readability. But I assume AoC makes you run this on a much bigger input as well.
- You also don't need to construct the calibration number as a string. `first*10 + second` gives the calibration number.
- When finding the digits, you can do a time-space tradeoff by creating a hashmap that maps each char 0-9 to the corresponding digit. Plugging the chars into this map is probably faster than parsing the string to an integer.
- You don't need a regex for this. To find `first` you can simply iterate through the line until you find a digit. To find `second` you do the same but in reverse. This is more efficient than running a regex.
- For a problem as small as the example, it doesn't matter and arguably the regex adds readability. But I assume AoC makes you run this on a much bigger input as well.
- You also don't need to construct the calibration number as a string. `first*10 + second` gives the calibration number.
- When finding the digits, you can do a time-space tradeoff by creating a hashmap that maps each char 0-9 to the corresponding digit. Plugging the chars into this map is probably faster than parsing the string to an integer.
#1: Initial revision
by
matthewsnyder
·
2024-07-17T06:10:56Z (4 months ago)
You don't need a regex for this. To find `first` you simply iterate through the line until you find a digit. To find `second` you do the same but in reverse. This is more efficient than running a regex. For a problem as small as the example, it doesn't matter and arguably the regex adds readability. But I assume AoC makes you run this on a much bigger input as well. You also don't need to construct the calibration number as a string. `first*10 + second` gives the calibration number. When finding the digits, you can do a time-space tradeoff by creating a hashmap that maps each char 0-9 to the corresponding digit. Plugging the chars into this map is probably faster than parsing the string to an integer.