2022 day 15 (C) part 1 (dirty and even more)

2022/day15/README.org

@@ -137,3 +137,25 @@ a beacon cannot be present.
 
 Consult the report from the sensors you just deployed. /In the row where
 =y=2000000=, how many positions cannot contain a beacon?/
+
+Your puzzle answer was =5176944=.
+
+The first half of this puzzle is complete! It provides one gold star: *
+
+** --- Part Two ---
+Your handheld device indicates that the distress signal is coming from a
+beacon nearby. The distress beacon is not detected by any sensor, but
+the distress beacon must have =x= and =y= coordinates each no lower than
+=0= and no larger than =4000000=.
+
+To isolate the distress beacon's signal, you need to determine its
+/tuning frequency/, which can be found by multiplying its =x= coordinate
+by =4000000= and then adding its =y= coordinate.
+
+In the example above, the search space is smaller: instead, the =x= and
+=y= coordinates can each be at most =20=. With this reduced search area,
+there is only a single position that could have a beacon: =x=14, y=11=.
+The tuning frequency for this distress beacon is =56000011=.
+
+Find the only possible position for the distress beacon. /What is its
+tuning frequency?/