14!

14/14.py

@@ -0,0 +1,55 @@
+from collections import defaultdict
+import sys
+
+from pprint import pprint
+
+
+def part_x(template: str, pairs: list[tuple[str, str, str]], iterations=10) -> int:
+    duos = defaultdict(int)
+
+    for i in range(len(template) - 1):
+        duos[template[i : i + 2]] += 1
+
+    for i in range(iterations):
+        next_duos = defaultdict(int)
+
+        for duo, n in duos.items():
+            inserted = pairs[duo]
+            next_duos[duo[0] + inserted] += n
+            next_duos[inserted + duo[1]] += n
+
+        duos = next_duos
+
+    print(duos)
+    letter_counts = count_occurrences(duos, template)
+    return max(letter_counts.values()) - min(letter_counts.values())
+
+
+def count_occurrences(duos: dict[str, int], template: str):
+    letter_counts = defaultdict(int)
+
+    letter_counts[template[0]] = 1
+    letter_counts[template[-1]] = 1
+
+    for duo, count in duos.items():
+        letter_counts[duo[0]] += count
+        letter_counts[duo[1]] += count
+
+    letter_counts = dict(map(lambda kv: (kv[0], kv[1] // 2), letter_counts.items()))
+
+    return letter_counts
+
+
+if __name__ == "__main__":
+    template = sys.stdin.readline().strip()
+    sys.stdin.readline()
+
+    pairs = {}
+
+    for line in sys.stdin.readlines():
+        A = line[0:2]
+        C = line[6]
+        pairs[A] = C
+
+    print("Part One:", part_x(template, pairs))
+    print("Part Two:", part_x(template, pairs, 40))