My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Add solution for 2023/09
+39
+39
2023/day09.py
+39
2023/day09.py
···
1
+
import fileinput
2
+
3
+
4
+
part_1 = 0
5
+
part_2 = 0
6
+
7
+
for line in fileinput.input():
8
+
row = [int(x) for x in line.split()]
9
+
10
+
# Build up triangle.
11
+
triangle = [row[:]]
12
+
13
+
while any(n != 0 for n in triangle[-1]):
14
+
row = []
15
+
for a, b in zip(triangle[-1], triangle[-1][1:]):
16
+
row.append(b - a)
17
+
18
+
triangle.append(row)
19
+
20
+
triangle.reverse()
21
+
22
+
# Extrapolate right column.
23
+
right = [0]
24
+
for *_, n in triangle[1:]:
25
+
right.append(right[-1] + n)
26
+
27
+
part_1 += right[-1]
28
+
29
+
# Extrapolate left column.
30
+
left = [0]
31
+
for n, *_ in triangle[1:]:
32
+
left.append(n - left[-1])
33
+
34
+
part_2 += left[-1]
35
+
36
+
37
+
print("Part 1:", part_1)
38
+
print("Part 2:", part_2)
39
+