My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Add 2017/24
+110
+51
2017/day24.py
+51
2017/day24.py
···
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import fileinput
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from collections import defaultdict, deque
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def bridge_bfs(i, port):
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def bridge_strength(ports):
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"""Returns the strength of a bridge given its ports."""
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return sum(ports) * 2 - ports[0] - ports[-1]
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# (port_index, port_list, seen_indices)
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horizon = deque([(i, [port], set([i]))])
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strongest = 0
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while horizon:
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longest = 0
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for _ in range(len(horizon)):
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i, ports, seen = horizon.popleft()
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seen.add(i)
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bridge = BRIDGES[i]
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port = bridge[0] if bridge[1] == ports[-1] else bridge[1]
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next_ports = ports + [port]
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strength = bridge_strength(next_ports)
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strongest = max(strongest, strength)
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longest = max(longest, strength)
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for p in BRIDGE_PORTS[port]:
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if p not in seen:
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horizon.append((p, list(next_ports), set(seen)))
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return strongest, longest
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BRIDGES = []
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BRIDGE_PORTS = defaultdict(list)
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for i, line in enumerate(fileinput.input()):
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x, y = [int(x) for x in line.split('/')]
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BRIDGES.append((x, y))
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BRIDGE_PORTS[x].append(i)
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BRIDGE_PORTS[y].append(i)
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for i in BRIDGE_PORTS[0]:
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strongest, longest = bridge_bfs(i, 0)
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print "Strength of strongest bridge:", strongest
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print "Strength of longest bridge:", longest
+57
2017/inputs/24.txt
+57
2017/inputs/24.txt
···
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48/14