kobo

y2021/p22.py

@@ -0,0 +1,57 @@
+import re
+
+
+def intersect(cube, other):
+    return not (
+        cube[1] <= other[0] or
+        cube[0] >= other[1] or
+        cube[3] <= other[2] or
+        cube[2] >= other[3] or
+        cube[5] <= other[4] or
+        cube[4] >= other[5]
+    )
+
+
+def insert(cube, val):
+    to_break = {other for other in seen if intersect(cube, other)}
+    for cu in to_break:
+        seen.discard(cu)
+
+    xAs, xBs, yAs, yBs, zAs, zBs = zip(*{cube} | to_break)
+    xs = sorted(set(xAs + xBs))
+    ys = sorted(set(yAs + yBs))
+    zs = sorted(set(zAs + zBs))
+    N = 0
+    for i in range(len(xs) - 1):
+        for j in range(len(ys) - 1):
+            for k in range(len(zs) - 1):
+                new = (xs[i], xs[i + 1], ys[j], ys[j + 1], zs[k], zs[k + 1])
+
+                if val == 'off' and intersect(new, cube):
+                    seen.discard(new)
+
+                elif val == 'on' and intersect(new, cube):
+                    seen.add(new)
+
+                elif any(intersect(old, new) for old in to_break):
+                    seen.add(new)
+
+
+def volume(xA, xB, yA, yB, zA, zB):
+    return abs(xB - xA) * abs(yB - yA) * abs(zB - zA)
+
+
+text = open(0).read()
+cubes = {}
+for line in text.splitlines():
+    val = line.split()[0]
+    xA, xB, yA, yB, zA, zB = [int(n) for n in re.findall(r'-?\d+', line)]
+    cubes[xA, xB + 1, yA, yB + 1, zA, zB + 1] = val
+
+
+seen = set()
+for i, (cube, val) in enumerate(cubes.items(), 1):
+    insert(cube, val)
+    if i == 20:
+        print(sum(volume(*cu) for cu in seen))
+print(sum(volume(*cu) for cu in seen))