2019 day 6 and 7

2019/d6.py

@@ -0,0 +1,57 @@
+from lib import get_data, str_to_ints
+from collections import defaultdict
+
+
+def part_1(data):
+    orbits = defaultdict(list)
+    for line in data.splitlines():
+        a, b = line.split(")")
+        orbits[a].append(b)
+
+    count = 0
+    for key in orbits.keys():
+        seen = set()
+        around = list(orbits[key])
+        while around:
+            a = around.pop()
+            count += 1
+            if a in orbits:
+                for o in orbits[a]:
+                    if o not in seen:
+                        around.append(o)
+            seen.add(a)
+    print(count)
+
+
+def part_2(data):
+    g = defaultdict(list)
+    for line in data.splitlines():
+        a, b = line.split(")")
+        g[a].append(b)
+        g[b].append(a)
+
+    seen = set()
+    nodes = ["YOU"]
+    steps = 0
+    while True:
+        new_nodes = []
+        for node in nodes:
+            seen.add(node)
+            for nb in g[node]:
+                if nb not in seen:
+                    new_nodes.append(nb)
+                if nb == "SAN":
+                    print(steps - 1)
+                    return
+        nodes = new_nodes
+        steps += 1
+
+
+def main():
+    data = get_data(__file__)
+    part_1(data)
+    part_2(data)
+
+
+if __name__ == "__main__":
+    main()