feat: days 1 2 3 done with duckdb

solutions/03.sql

@@ -0,0 +1,69 @@
+create or replace table day03_data as
+  select bank
+  from read_csv(
+    'inputs/03/input.txt',
+    header = false,
+    columns = { 'bank': 'VARCHAR' }
+  );
+create or replace table day03_test as
+  select bank
+  from read_csv(
+    'inputs/03/test.txt',
+    header = false,
+    columns = { 'bank': 'VARCHAR' }
+  );
+
+with with_best as (
+  select bank,
+  coalesce((
+    select max(digit),
+    from generate_series(2, 9) as t(digit)
+    where contains(bank[:-2], digit::string) is true
+  ), 1) as best
+  from day03_test
+),
+with_best_pos as (
+  select *,
+    instr(bank, best::string) as best_pos,
+    bank[best_pos+1:],
+    coalesce((
+    select max(digit)
+      from generate_series(2, 9) as t(digit)
+      where contains(bank[best_pos+1:], digit::string) is true
+    ), 1) as second_best
+  from with_best
+)
+select sum(best * 10 + second_best) as part1
+from with_best_pos
+;
+
+with recursive seq as (
+  select 
+    bank,
+    12 as step,
+    '' as digits,
+    0 as pos,
+    bank[0:-12] as sub,
+  from day03_data
+
+  union all
+
+  select
+    s.bank,
+    s.step - 1 as new_step,
+    s.digits || max_digit::string as digits,
+s.pos+instr(s.sub, max_digit::string) as new_pos,
+    s.bank[new_pos+1:-new_step] as sub,
+  from seq s
+  join lateral (
+    select max(digit) as max_digit
+    from generate_series(1,9) as t(digit)
+    where contains(s.sub, digit::string)
+  ) as m
+  on s.step > 0
+)
+select sum(digits::hugeint) as total
+from seq
+where step = 0
+;
+