2020/5v2

y2020/p05.py

@@ -1,22 +1,14 @@
 import sys
 
 
-sids = []
-for line in sys.stdin.read().splitlines():
-    rows = list(range(1, 128))
-    for char in line[:7]:
-        rows = [rows[:len(rows)//2], rows[len(rows)//2:]]['FB'.index(char)]
-    row, = rows
+def bin(string, trans=str.maketrans('FBLR', '0101')):
+    return int(string.translate(trans), 2)
 
-    cols = list(range(8))
-    for char in line[7:]:
-        cols = [cols[:len(cols)//2], cols[len(cols)//2:]]['LR'.index(char)]
-    col, = cols
 
-    sids.append(row * 8 + col)
+sids = {bin(ln[:7]) * 8 + bin(ln[7:]) for ln in sys.stdin.read().splitlines()}
 
 ans1 = max(sids)
-ans2, = set(range(min(sids), max(sids) + 1)).difference(sids)
-
 print(ans1)
+
+ans2, = sids ^ set(range(min(sids), max(sids) + 1))
 print(ans2)