My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Optimize 2017/24 solution
Remove components of the form `X/X` from the graph, which reduces
runtime from ~10s to ~500ms.
+13
-5
+13
-5
2017/day24.py
+13
-5
2017/day24.py
···
25
25
next_ports = ports + [port]
26
26
strength = bridge_strength(next_ports)
27
27
28
+
# See if we can incorporate any `X/X` components
29
+
strength += sum(2 * p for p in BRIDGE_EXTRAS if p in next_ports)
30
+
28
31
strongest = max(strongest, strength)
29
32
longest = max(longest, strength)
30
33
···
37
40
38
41
BRIDGES = []
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42
BRIDGE_PORTS = defaultdict(list)
43
+
BRIDGE_EXTRAS = [] # tracks components of type `X/X`
40
44
41
-
for i, line in enumerate(fileinput.input()):
42
-
x, y = [int(x) for x in line.split('/')]
45
+
for line in fileinput.input():
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+
x, y = (int(x) for x in line.split('/'))
43
47
44
-
BRIDGES.append((x, y))
45
-
BRIDGE_PORTS[x].append(i)
46
-
BRIDGE_PORTS[y].append(i)
48
+
if x != y:
49
+
i = len(BRIDGES)
50
+
BRIDGES.append((x, y))
51
+
BRIDGE_PORTS[x].append(i)
52
+
BRIDGE_PORTS[y].append(i)
53
+
else:
54
+
BRIDGE_EXTRAS.append(x)
47
55
48
56
for i in BRIDGE_PORTS[0]:
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57
strongest, longest = bridge_bfs(i, 0)