Files
adventofcode/2025/day04/solve.sql

48 lines
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SQL

-- First import raw data into a table so we can work
CREATE TABLE raw_data(line_data VARCHAR NOT NULL);
.import --csv './sample.txt' raw_data
-- Then use the auto-incrementing ID to add a y coordinate
CREATE TABLE grid_lines(
y INTEGER PRIMARY KEY,
line_data VARCHAR NOT NULL
);
INSERT INTO grid_lines(line_data)
SELECT line_data
FROM raw_data;
-- Now create a table to hold the paper rolls
CREATE TABLE rolls(
x INTEGER NOT NULL,
y INTEGER NOT NULL,
PRIMARY KEY (x, y)
);
WITH RECURSIVE cte AS (
SELECT y,
1 x,
line_data,
substr(line_data, 1, 1) c
FROM grid_lines
UNION ALL
SELECT y,
x + 1,
line_data,
substr(line_data, x + 1, 1)
FROM cte
WHERE x <= length(line_data)
)
INSERT INTO rolls
SELECT x,
y
FROM cte
WHERE c = '@';
-- Now compute part 1
SELECT COUNT(*) as part1
FROM rolls r
WHERE (
SELECT COUNT(*) - 1
FROM rolls o
WHERE o.x >= r.x - 1
AND o.x <= r.x + 1
AND o.y >= r.y - 1
AND o.y <= r.y + 1
) < 4;