-
Notifications
You must be signed in to change notification settings - Fork 0
/
06.py
73 lines (60 loc) · 1.95 KB
/
06.py
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
import math
import os
inputFile = open(os.path.dirname(__file__) + '/input.txt', 'r')
lines = inputFile.readlines()
inputFile.close()
def part_one():
# Performs recursive DFS
def get_orbits(orbited, orbits):
if orbited not in graph:
return 0
total = 0
orbits += 1
for orbiter in graph[orbited]:
total += orbits + get_orbits(orbiter, orbits)
return total
# Construct directed graph
graph = {}
for line in lines:
orbited, orbiter = line.split(')')
if orbited in graph:
graph[orbited].append(orbiter[:-1])
else:
graph[orbited] = [orbiter[:-1]]
return get_orbits('COM', 0)
def part_two():
# Construct undirected graph
graph = {}
start = destination = ''
for line in lines:
orbited, orbiter = line.split(')')
if orbiter[:-1] == 'YOU':
start = orbited
elif orbiter[:-1] == 'SAN':
destination = orbited
if orbited in graph:
graph[orbited].append(orbiter[:-1])
else:
graph[orbited] = [orbiter[:-1]]
if orbiter[:-1] in graph:
graph[orbiter[:-1]].append(orbited)
else:
graph[orbiter[:-1]] = [orbited]
# Dijkstra's algorithm
distances = {start: 0}
visited = {}
while len(visited) < len(graph):
min_distance = -1
min_key = ''
for key in graph:
distance = math.inf if key not in distances else distances[key]
if key not in visited and (min_distance == -1 or distance < min_distance):
min_distance = distance
min_key = key
visited[min_key] = 1
for vertex in graph[min_key]:
if vertex not in distances or min_distance + 1 < distances[vertex]:
distances[vertex] = min_distance + 1
return distances[destination]
print(f'Part one: {part_one()}')
print(f'Part two: {part_two()}')