Solve 2018 day 14

2018/d14.py

@@ -0,0 +1,62 @@
+def part_1(data):
+    num = int(data.strip())
+    recipes = [3, 7]
+    i, j = 0, 1
+
+    while True:
+        s = recipes[i] + recipes[j]
+        ss = str(s)
+        if len(ss) == 1:
+            recipes.append(s)
+        elif len(ss) == 2:
+            recipes.append(int(ss[0]))
+            recipes.append(int(ss[1]))
+        else:
+            assert False
+
+        i = (i + 1 + recipes[i]) % len(recipes)
+        j = (j + 1 + recipes[j]) % len(recipes)
+        if i == j:
+            j = (j + 1) % len(recipes)
+        if len(recipes) > num + 10:
+            print("".join(map(str, recipes[num : num + 10])))
+            break
+
+
+def part_2(data):
+    target = list(map(int, data.strip()))
+    recipes = [3, 7]
+
+    i, j = 0, 1
+    while True:
+        s = recipes[i] + recipes[j]
+        if s < 10:
+            recipes.append(s)
+        elif s < 100:
+            recipes.append(s // 10)
+            recipes.append(s % 10)
+        else:
+            assert False
+
+        i = (i + 1 + recipes[i]) % len(recipes)
+        j = (j + 1 + recipes[j]) % len(recipes)
+        if i == j:
+            j = (j + 1) % len(recipes)
+
+        if recipes[-len(target) :] == target:
+            print(len(recipes) - len(target))
+        elif recipes[-len(target) - 1 : -1] == target:
+            print(len(recipes) - len(target) - 1)
+            break
+
+
+def main():
+    input_file = __file__.replace(".py", ".txt")
+    with open(input_file) as f:
+        data = f.read()
+    part_1(data)
+    part_2(data)
+
+
+if __name__ == "__main__":
+    main()

README.md

@@ -102,7 +102,8 @@ written in Python.
 - Day 11: 22:52
 - Day 12: 180:00
 - Day 13: 73:09
-- Day 14:
+- Day 14: 20:48
+- Day 15:
 
 
 # 2022