[2019/6] solved

2019/6/example

@@ -0,0 +1,11 @@
+COM)B
+B)C
+C)D
+D)E
+E)F
+B)G
+G)H
+D)I
+E)J
+J)K
+K)L

2019/6/example2

@@ -0,0 +1,13 @@
+COM)B
+B)C
+C)D
+D)E
+E)F
+B)G
+G)H
+D)I
+E)J
+J)K
+K)L
+K)YOU
+I)SAN

2019/6/script.py

@@ -0,0 +1,41 @@
+from GhostyUtils import aoc
+from collections import defaultdict
+
+
+def bfs(graph, start, end):
+    visited = set()
+    frontier = [[start]]
+    while frontier:
+        path = frontier.pop(0)
+        node = path[-1]
+        if node == end:
+            return path
+
+        for new_node in graph[node]:
+            if new_node in visited:
+                continue
+            frontier.append(path + [new_node])
+            visited.add(new_node)
+
+
+def main():
+    orbits = defaultdict(set)
+    satellites = set()
+    for orbit in aoc.read_lines():
+        body, satellite = orbit.split(')')
+        orbits[body].add(satellite)
+        orbits[satellite].add(body)
+        satellites.add(satellite)
+
+    total_orbits = 0
+    for satellite in satellites:
+        path = bfs(orbits, 'COM', satellite)
+        total_orbits += len(path) - 1
+    print('p1:', total_orbits)
+
+    path = bfs(orbits, 'YOU', 'SAN')
+    print('p2:', len(path)-2-1)
+
+
+if __name__ == "__main__":
+    main()