1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
|
from math import ceil
class SnailfishItem:
def __init__(self, parent, contents):
self.parent = parent
self.atomic = not isinstance(contents, list)
if not self.atomic:
if isinstance(contents[0], SnailfishItem):
self.left = contents[0]
self.left.parent = self
else:
self.left = SnailfishItem(self, contents[0])
if isinstance(contents[1], SnailfishItem):
self.right = contents[1]
self.right.parent = self
else:
self.right = SnailfishItem(self, contents[1])
else:
self.contents = contents
def __str__(self):
if self.atomic:
return str(self.contents)
else:
return "[%s, %s]" % (str(self.left), str(self.right))
def add(self, other):
if self.atomic and other.atomic:
self.contents += other.contents
else:
if self.atomic:
self.left = SnailfishItem(self, self.contents)
else:
self.left = SnailfishItem(self, [self.left, self.right])
self.atomic = False
self.right = other
other.parent = self
self.contents = None
while self.reduce():
pass
def check_explodes(self, n=0):
if self.atomic:
return False
elif n < 4:
return self.left.check_explodes(n+1) or self.right.check_explodes(n+1)
self.explode_left()
self.explode_right()
self.atomic = True
self.contents = 0
self.left = None
self.right = None
return True
def check_splits(self):
if not self.atomic:
return self.left.check_splits() or self.right.check_splits()
elif self.contents < 10:
return False
self.atomic = False
self.left = SnailfishItem(self, self.contents // 2)
self.right = SnailfishItem(self, ceil(self.contents / 2))
self.contents = None
return True
def reduce(self, n=0):
if not self.atomic:
return self.check_explodes(n) or self.check_splits()
else:
return self.check_splits()
def explode_left(self):
last_node = self
node = self.parent
while node != None and node.left == last_node:
last_node = node
node = last_node.parent
if node == None:
return # leftmost element of tree
node = node.left
while not node.atomic:
node = node.right
node.add(self.left)
def explode_right(self):
last_node = self
node = self.parent
while node != None and node.right == last_node:
last_node = node
node = last_node.parent
if node == None:
return # rightmost element of tree
node = node.right
while not node.atomic:
node = node.left
node.add(self.right)
def magnitude(self):
if self.atomic:
return self.contents
else:
return (3 * self.left.magnitude()) + (2 * self.right.magnitude())
lines = open("./input").read().strip().split("\n")
val = SnailfishItem(None, eval(lines[0])) # cope, seethe, mald, etc.
for line in lines[1:]:
val.add(SnailfishItem(None, eval(line)))
print("Part 1: %d" % val.magnitude())
max_mag = 0
for x_str in lines:
for y_str in lines:
if x_str == y_str:
continue
x = SnailfishItem(None, eval(x_str))
x.add(SnailfishItem(None, eval(y_str)))
if x.magnitude() > max_mag:
max_mag = x.magnitude()
print("Part 2: %d" % max_mag)
|
