aoc_1201.md

Day 1

Link to puzzle(s) 🟢 🟢

Part one

The newly-improved calibration document consists of lines of text; each line originally contained a specific calibration value that the Elves now need to recover. On each line, the calibration value can be found by combining the first digit and the last digit (in that order) to form a single two-digit number.

Consider your entire calibration document. What is the sum of all of the calibration values?

SELECT SUM(LEFT(r, 1)::int * 10 + RIGHT(r, 1)::int) AS part1
FROM (
	SELECT regexp_replace(input, '[^\d]', '', 'g') AS r
	FROM aoc_1201
);

Part two

Your calculation isn't quite right. It looks like some of the digits are actually spelled out with letters: one, two, three, four, five, six, seven, eight, and nine also count as valid "digits".

Equipped with this new information, you now need to find the real first and last digit on each line.

WITH
    lines AS (
        SELECT regexp_split_to_table(input, '\n') AS line
        FROM aoc_1201
    ),
    slices AS (
        SELECT line, index, substring(line, index, width) AS slice
        FROM
            lines,
            generate_series(1, length(line)) AS index,
            generate_series(1, 5) AS width
    ),
    numbers (t, n) AS (
        VALUES ('0', 0), ('1', 1), ('2', 2), ('3', 3), ('4', 4), ('5', 5), ('6', 6), ('7', 7), ('8', 8), ('9', 9),
               ('zero', 0), ('one', 1), ('two', 2), ('three', 3), ('four', 4), ('five', 5), ('six', 6), ('seven', 7), ('eight', 8), ('nine', 9)
    ),
    findings AS (
        SELECT line, index, n AS number
        FROM slices, numbers
        WHERE slices.slice = numbers.t
    ),
    first AS ( SELECT DISTINCT ON (line) line, number AS f FROM findings ORDER BY line, index ),
    last AS ( SELECT DISTINCT ON (line) line, number AS l FROM findings ORDER BY line, index DESC )
SELECT SUM(f * 10 + l)
FROM first, last
WHERE first.line = last.line

Contributors

Day 1 was brought to you by: @chaas, @def-, @doy-materialize, @frankmcsherry, @josharenberg, @morsapaes, @nrainer-materialize