My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Add 2022/20
+96
+96
2022/day20.py
+96
2022/day20.py
···
1
+
import fileinput
2
+
3
+
4
+
class Node:
5
+
def __init__(self, i, val):
6
+
self.i = i
7
+
self.val = val
8
+
self.back = None
9
+
self.next = None
10
+
11
+
12
+
# Parse problem input.
13
+
INPUT = [int(x) for x in fileinput.input()]
14
+
15
+
16
+
def construct_problem(problem_input, decryption_key=1):
17
+
numbers = []
18
+
first = None
19
+
last = None
20
+
zero = None
21
+
for i, num in enumerate(problem_input):
22
+
node = Node(i, num * decryption_key)
23
+
24
+
if num == 0:
25
+
zero = node
26
+
27
+
if first is None:
28
+
first = node
29
+
else:
30
+
node.back = last
31
+
32
+
if last is not None:
33
+
last.next = node
34
+
35
+
last = node
36
+
numbers.append(node)
37
+
38
+
last.next = first
39
+
first.back = last
40
+
41
+
return numbers, zero
42
+
43
+
44
+
def move_number(node, mod):
45
+
n = node.val % mod
46
+
if n == 0:
47
+
return
48
+
49
+
# Keep track of old parent/child.
50
+
parent = node.back
51
+
child = node.next
52
+
53
+
# Find the next location.
54
+
curr = node
55
+
for _ in range(n):
56
+
curr = curr.next
57
+
58
+
# Point new parent/child to node and vice versa.
59
+
desc = curr.next
60
+
61
+
desc.back = node
62
+
curr.next = node
63
+
node.back = curr
64
+
node.next = desc
65
+
66
+
# Put the old parent/child together.
67
+
parent.next = child
68
+
child.back = parent
69
+
70
+
71
+
def mix(numbers):
72
+
for n in numbers:
73
+
move_number(n, len(numbers) - 1)
74
+
75
+
76
+
def get_grove_coordinates(curr):
77
+
vals = []
78
+
for i in range(3):
79
+
for _ in range(1000):
80
+
curr = curr.next
81
+
82
+
vals.append(curr.val)
83
+
84
+
return sum(vals)
85
+
86
+
87
+
# Solve part 1.
88
+
numbers, zero = construct_problem(INPUT)
89
+
mix(numbers)
90
+
print("Part 1:", get_grove_coordinates(zero))
91
+
92
+
# Solve part 2.
93
+
numbers, zero = construct_problem(INPUT, decryption_key=811589153)
94
+
for _ in range(10): mix(numbers)
95
+
print("Part 2:", get_grove_coordinates(zero))
96
+