day 6

6/a.py

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+with open("input.txt") as f:
+    pond = [int(i) for i in f.read().strip().split(",")]
+
+print("pond", pond)
+
+
+def simulate():
+    for i, fish in enumerate(pond[:]):
+        # print("i, fish", i, fish)
+        newfish = fish - 1
+        if newfish < 0:
+            newfish = 6
+            pond.append(8)
+        pond[i] = newfish
+
+
+for i in range(0, 80):
+    # print("pond", len(pond))
+    simulate()
+
+print("answer", len(pond))
+
+
+
+
+
+# each lanternfish creates a new lanternfish once every 7 days.
+
+# So, you can model each fish as a single number that represents the number of days until it creates a new lanternfish.
+
+# a new lanternfish would surely need slightly longer before it's capable of producing more lanternfish: two more days for its first cycle.
+
+# list of the ages of several hundred nearby lanternfish (your puzzle input).
+
+# Find a way to simulate lanternfish. How many lanternfish would there be after 80 days?
+
+
+

6/b.py

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+from collections import defaultdict
+
+with open("input.txt") as f:
+    pond = [int(i) for i in f.read().strip().split(",")]
+
+sea = defaultdict(lambda: 0)
+
+
+for fish in pond:
+    sea[fish] += 1
+
+
+for i in range(0, 256):
+    # print(i, dict(sea))
+    newsea = defaultdict(lambda: 0)
+
+    for fish, count in sea.items():
+        newfish = fish - 1
+        if newfish < 0:
+            newfish = 6
+            newsea[8] += count
+        newsea[newfish] += count
+
+    sea = newsea
+    # print(i, dict(sea))
+    # print()
+
+
+print(sum(sea.values()))

6/input.txt

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+1,1,5,2,1,1,5,5,3,1,1,1,1,1,1,3,4,5,2,1,2,1,1,1,1,1,1,1,1,3,1,1,5,4,5,1,5,3,1,3,2,1,1,1,1,2,4,1,5,1,1,1,4,4,1,1,1,1,1,1,3,4,5,1,1,2,1,1,5,1,1,4,1,4,4,2,4,4,2,2,1,2,3,1,1,2,5,3,1,1,1,4,1,2,2,1,4,1,1,2,5,1,3,2,5,2,5,1,1,1,5,3,1,3,1,5,3,3,4,1,1,4,4,1,3,3,2,5,5,1,1,1,1,3,1,5,2,1,3,5,1,4,3,1,3,1,1,3,1,1,1,1,1,1,5,1,1,5,5,2,1,5,1,4,1,1,5,1,1,1,5,5,5,1,4,5,1,3,1,2,5,1,1,1,5,1,1,4,1,1,2,3,1,3,4,1,2,1,4,3,1,2,4,1,5,1,1,1,1,1,3,4,1,1,5,1,1,3,1,1,2,1,3,1,2,1,1,3,3,4,5,3,5,1,1,1,1,1,1,1,1,1,5,4,1,5,1,3,1,1,2,5,1,1,4,1,1,4,4,3,1,2,1,2,4,4,4,1,2,1,3,2,4,4,1,1,1,1,4,1,1,1,1,1,4,1,5,4,1,5,4,1,1,2,5,5,1,1,1,5