My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Add solution for 2024/05
+52
+52
2024/day05.py
+52
2024/day05.py
···
1
+
import fileinput
2
+
from collections import defaultdict
3
+
4
+
from utils import parse_nums
5
+
6
+
7
+
def is_unordered(graph, update):
8
+
"""Returns -1 if ordered, else the index of the first bad page."""
9
+
for i, n in enumerate(update):
10
+
if any(n in graph[m] for m in update[i+1:]):
11
+
return i
12
+
13
+
return -1
14
+
15
+
def mid(lst):
16
+
return lst[(len(lst) - 1) // 2]
17
+
18
+
19
+
on_updates = False
20
+
graph = defaultdict(set)
21
+
updates = []
22
+
for line in fileinput.input():
23
+
if on_updates:
24
+
updates.append(parse_nums(line))
25
+
else:
26
+
if line.strip():
27
+
x, y = parse_nums(line)
28
+
graph[x].add(y)
29
+
else:
30
+
on_updates = True
31
+
32
+
part_1 = 0
33
+
part_2 = 0
34
+
35
+
for update in updates:
36
+
if is_unordered(graph, update) == -1:
37
+
part_1 += mid(update)
38
+
else:
39
+
while True:
40
+
swap = False
41
+
for i, n in enumerate(update):
42
+
afters = update[i+1:]
43
+
if any(n in graph[a] for a in afters):
44
+
update[i], update[i + 1] = update[i + 1], update[i]
45
+
swap = True
46
+
if not swap:
47
+
break
48
+
49
+
part_2 += mid(update)
50
+
51
+
print("Part 1:", part_1)
52
+
print("Part 2:", part_2)