My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Prune rearrangements of identical states
+10
-5
+10
-5
2016/day11.py
+10
-5
2016/day11.py
···
23
23
return True
24
24
25
25
26
+
def ordered(state):
27
+
substate = sorted(zip(state[::2], state[1::2]))
28
+
return tuple(item for subl in substate for item in subl)
29
+
26
30
27
31
def solve(state, start_floor=0):
28
32
if start_floor == 3 and complete(state):
···
43
47
moves.extend([(2, floor + 1), (1, floor + 1)])
44
48
45
49
if floor > 0:
46
-
moves.extend([(1, floor - 1), (2, floor - 1)])
50
+
# Don't move downstairs if the floors below are empty
51
+
if any(f < floor for f in state):
52
+
moves.extend([(1, floor - 1), (2, floor - 1)])
47
53
48
54
moved_two_up = False
49
55
moved_one_down = False
···
62
68
if complete(next_state):
63
69
return steps + 1
64
70
65
-
if valid(next_state) and (new_floor, next_state) not in seen:
66
-
pair = (new_floor, next_state)
67
-
new_horizon.append(pair)
68
-
seen.add(pair)
71
+
if valid(next_state) and (new_floor, ordered(next_state)) not in seen:
72
+
new_horizon.append((new_floor, next_state))
73
+
seen.add((new_floor, ordered(next_state)))
69
74
70
75
if n == 2 and new_floor > floor:
71
76
moved_two_up = True