Update day 14 solution

Use collections.counter instead of collections.defaultdict

day-14/day-14.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 from pathlib import Path
-from collections import defaultdict
+from collections import Counter
 
 
 def solve(input, part, num_cycles):
@@ -8,23 +8,16 @@ def solve(input, part, num_cycles):
     template = input[0].strip()
     rules = {k: v
              for line in input[2:] for k, v in [line.strip().split(' -> ')]}
-    counts = defaultdict(int)
-    for i in range(len(template) - 1):
-        counts[template[i: i + 2]] += 1
+    counts = Counter([template[i: i + 2] for i in range(len(template - 1))])
+    char_counts = Counter(template)
     for _ in range(num_cycles):
         for k, c in counts.copy().items():
             if k in rules:
                 counts[k] -= c
                 counts[k[0] + rules[k]] += c
                 counts[rules[k] + k[1]] += c
-    char_counts = defaultdict(int)
-    for k in counts:
-        char_counts[k[0]] += counts[k]
-        char_counts[k[1]] += counts[k]
-    char_counts[template[0]] += 1
-    char_counts[template[-1]] += 1
-    counts = [char_counts[k] // 2 for k in char_counts]
-    result = max(counts) - min(counts)
+                char_counts[rules[k]] += 1
+    result = char_counts.most_common(1)[1] - char_counts.most_common()[-1][1]
     print("Part", part, "result:", result)