My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Update day11.py
+13
-14
+13
-14
2016/day11.py
+13
-14
2016/day11.py
···
3
3
from itertools import combinations
4
4
5
5
6
-
def complete(state):
7
-
return all(f == 3 for f in state)
8
-
9
-
10
6
def valid(state):
7
+
"""Returns whether the current state is valid or not."""
11
8
gens = set(state[::2])
12
9
for i, floor in enumerate(state):
13
10
# Element is a chip if it has an odd index
14
11
if i % 2 == 1:
15
-
# Its matching generator is on the same floor, so it's fine
16
-
if state[i-1] == floor:
12
+
# Chip's matching generator is on the same floor
13
+
if state[i - 1] == floor:
17
14
continue
18
15
19
16
# There is another generator on the floor
···
24
21
25
22
26
23
def ordered(state):
27
-
substate = sorted(zip(state[::2], state[1::2]))
28
-
return tuple(item for subl in substate for item in subl)
24
+
"""Returns an ordered version of the state (to improve node pruning)."""
25
+
sorted_state = sorted(zip(state[::2], state[1::2]))
26
+
return tuple(item for subl in sorted_state for item in subl)
29
27
30
28
31
29
def solve(state, start_floor=0):
32
-
if start_floor == 3 and complete(state):
33
-
return 0
34
-
35
30
horizon = [(start_floor, state)]
36
31
steps = 0
37
32
seen = set()
···
43
38
can_move = [i for i, f in enumerate(state) if f == floor]
44
39
moves = []
45
40
46
-
if floor < 3:
41
+
if floor < TOP_FLOOR:
47
42
moves.extend([(2, floor + 1), (1, floor + 1)])
48
43
49
44
if floor > 0:
···
65
60
for move in combinations(can_move, n):
66
61
next_state = tuple(new_floor if i in move else f for i, f in enumerate(state))
67
62
68
-
if complete(next_state):
63
+
# All items are on the top floor, so we're done
64
+
if all(f == TOP_FLOOR for f in next_state):
69
65
return steps + 1
70
66
71
67
if valid(next_state) and (new_floor, ordered(next_state)) not in seen:
···
81
77
steps += 1
82
78
83
79
80
+
TOP_FLOOR = None
84
81
generators = {}
85
82
microchips = {}
86
83
···
90
87
for chip in re.findall(r'(\w+)-compatible microchip', line):
91
88
microchips[chip] = i
92
89
90
+
TOP_FLOOR = i
91
+
93
92
94
93
STATE = []
95
94
···
102
101
print "Minimum number of steps:", solve(STATE)
103
102
104
103
STATE = tuple(list(STATE) + [0, 0, 0, 0])
105
-
print "With four new objects:", solve(STATE)
104
+
print "Including 4 new objects:", solve(STATE)