2021 day8/python: add fast solution

2021/day8/fast.py

@@ -0,0 +1,16 @@
+#!/usr/bin/env python
+
+import sys
+from collections import Counter
+
+if __name__ == '__main__':
+    acc1 = 0
+    acc2 = 0
+    for line in sys.stdin.readlines():
+        inputs, outputs = line.split('|')
+        counter = Counter(c for cs in inputs for c in cs)
+        digits = [{17: 1, 25: 7, 30: 4, 34: 2, 37: 5, 39: 3, 41: 6, 42: 0, 49: 8, 45: 9}[sum(counter[c] for c in output)] for output in outputs.strip().split()]
+        acc1 += sum(digit in (1, 4, 7, 8) for digit in digits)
+        acc2 += int(''.join(str(digit) for digit in digits))
+    print(acc1)
+    print(acc2)