day 14

14/14.py

@@ -0,0 +1,61 @@
+#!/usr/bin/python3
+
+import sys, re
+
+mask = None
+
+def parse_mask(mask):
+    mask0 = mask1 = mask
+    mask0 = mask0.replace('X','1')
+    mask1 = mask1.replace('X','0')
+    return(int(mask0,2), int(mask1,2))
+
+def setbit(val, offset):
+    mask = 1 << offset
+    return (val | mask)
+
+def clearbit(val, offset):
+    mask = ~(1 << offset)
+    return (val & mask)
+
+def parse_mask2(val, mask):
+    mask = mask[::-1]
+    nums = [val]
+    for m in range(len(mask)):
+        t = []
+        for v in nums:
+            if mask[m] == 'X':
+                t.append(setbit(v, m))
+                t.append(clearbit(v, m))
+            else:
+                t.append(v)
+        nums = t
+    return nums
+
+p1 = {}
+p2 = {}
+mask0 = mask1 = 0
+tmask = ""
+for line in sys.stdin:
+    line = line.rstrip()
+
+    m = re.match(r'^mask \= (\S+)$', line)
+    if m is not None:
+        tmask = m.group(1)
+        (mask0, mask1) = parse_mask(tmask)
+        continue
+    
+    m = re.match(r'^mem\[(\d+)\] = (\d+)$', line)
+    p2pos = pos = int(m.group(1))
+    p2val = val = int(m.group(2))
+
+    val = val & mask0
+    val = val | mask1
+    p1[pos] = val
+
+    p2perms = parse_mask2(p2pos | mask1, tmask)
+    for p in p2perms:
+        p2[p] = p2val
+
+print(1, sum(p1.values()))
+print(2, sum(p2.values()))