day 11 part 2

day11/input

@@ -0,0 +1 @@
+6563348 67 395 0 6 4425 89567 739318

day11/sample1.in

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+Initial arrangement:
+125 17
+
+After 1 blink:
+253000 1 7
+
+After 2 blinks:
+253 0 2024 14168
+
+After 3 blinks:
+512072 1 20 24 28676032
+
+After 4 blinks:
+512 72 2024 2 0 2 4 2867 6032
+
+After 5 blinks:
+1036288 7 2 20 24 4048 1 4048 8096 28 67 60 32
+
+After 6 blinks:
+2097446912 14168 4048 2 0 2 4 40 48 2024 40 48 80 96 2 8 6 7 6 0 3 2

day11/sol.py

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+def solve(file):
+    nums = file.read().split()
+
+    for i in range(25):
+        if len(nums) < 100:
+            print(i, nums)
+        new = []
+        for n in nums:
+            if n == '0':
+                new.append('1')
+            elif len(n)%2 == 0:
+                new.append(n[:len(n)//2])
+                new.append(n[len(n)//2:].lstrip('0') or '0')
+            else:
+                new.append(str(int(n)*2024))
+        nums = new
+    print(len(nums))
+
+def solve2(file):
+    nums = file.read().split()
+
+    print(sum(evolve(n, 25) for n in nums))
+    print(sum(evolve(n, 75) for n in nums))
+
+book = {}
+def evolve(n, t):
+    if t == 0:
+        return 1
+    elif (n,t) in book:
+        return book[n,t]
+    else:
+        if n == '0':
+            x = evolve('1', t-1)
+        elif len(n)%2 == 0:
+            x = evolve(n[:len(n)//2], t-1)
+            x += evolve(n[len(n)//2:].lstrip('0') or '0', t-1)
+        else:
+            x = evolve(str(int(n)*2024), t-1)
+        book[n,t] = x
+        return x
+
+from io import StringIO
+#solve(StringIO("0 1 10 99 999"))
+solve2(StringIO("0 1 10 99 999"))
+#solve(open("input"))
+solve2(open("input"))