2021 day 6.

2021/day6.py

@@ -1,13 +1,21 @@
 import sys
-from collections import defaultdict
-from dataclasses import dataclass
 
-lines = sys.stdin.read().splitlines()
+values = [int(c) for c in sys.stdin.read().strip().split(",")]
+
+days = 256
+lanterns = {day: 0 for day in range(days)}
+for value in values:
+    for day in range(value, days, 7):
+        lanterns[day] += 1
+
+for day in range(days):
+    for day2 in range(day + 9, days, 7):
+        lanterns[day2] += lanterns[day]
 
 # part 1
-answer_1 = ...
+answer_1 = sum(v for k, v in lanterns.items() if k < 80) + len(values)
 print(f"answer 1 is {answer_1}")
 
 # part 2
-answer_2 = ...
+answer_2 = sum(lanterns.values()) + len(values)
 print(f"answer 2 is {answer_2}")