2018 day 5 part 1

2018/5/alchemy.py

@@ -0,0 +1,19 @@
+#!/usr/bin/env python3
+from string import ascii_lowercase, ascii_uppercase
+import fileinput
+import re
+
+
+def main():
+    removals = set(map(''.join, zip(ascii_lowercase, ascii_uppercase)))
+    removals = removals.union({r[::-1] for r in removals})
+    remove_regex = re.compile('({})'.format('|'.join(removals)))
+    line = next(fileinput.input()).strip()
+    count = 1
+    while count > 0:
+        line, count = remove_regex.subn('', line)
+    return len(line)
+
+
+if __name__ == '__main__':
+    print(main())