2020/18

y2020/p17.py

@@ -0,0 +1,47 @@
+import sys
+from itertools import product
+
+
+def span(n):
+    return list(range(-n - 1, n + 2))
+
+
+def neighbors(pos):
+    return {
+        tuple(t + dt for t, dt in zip(pos, deltas))
+        for deltas in product([-1, 0, 1], repeat=len(pos))
+        if set(deltas) != {0}
+    }
+
+
+def condition(known, pos):
+    active = pos in known
+    count = len(neighbors(pos) & known)
+    return (active and count in {2, 3}) or (not active and count in {3})
+
+
+def evolve(known, dims, n_cycles):
+    for _ in range(n_cycles):
+        dims = [n + 1 for n in dims]
+        known = {
+            pos
+            for pos in product(*map(span, dims))
+            if condition(known, pos)
+        }
+    return known
+
+
+text = sys.stdin.read()
+known = {
+    (x, y, 0)
+    for y, ln in enumerate(text.splitlines())
+    for x, char in enumerate(ln)
+    if char == '#'
+}
+dims = tuple([
+    max(x + 1 for x, _, _ in known),
+    max(y + 1 for _, y, _ in known),
+    max(z + 1 for _, _, z in known),
+])
+print(len(evolve(known, dims, 6)))
+print(len(evolve({pt + (0,) for pt in known}, dims + (1,), 6)))

y2020/p18.py

@@ -0,0 +1,31 @@
+import re
+import sys
+
+
+def reval1(ln):
+    a, *rest = ln.split()
+    for b, c in zip(*[iter(rest)] * 2):
+        a = eval(f'{a} {b} {c}')
+    return a
+
+
+def reval2(ln):
+    while '+' in ln:
+        ln = re.sub(r'\d+ \+ \d+', lambda m: str(eval(m.group(0))), ln)
+    return eval(ln)
+
+
+def process(ln, reval):
+    while '(' in ln:
+        ln = re.sub(r'\(([^\(\)]+)\)', lambda m: str(reval(m.group(1))), ln)
+    return reval(ln)
+
+
+text = sys.stdin.read()
+ans1 = 0
+ans2 = 0
+for ln in text.splitlines():
+    ans1 += int(process(ln, reval=reval1))
+    ans2 += int(process(ln, reval=reval2))
+print(ans1)
+print(ans2)