Solve a couple of 2017 problems.

2017/d12.py

@@ -0,0 +1,56 @@
+from lib import str_to_ints
+from collections import defaultdict
+
+
+def get_graph(data):
+    g = defaultdict(set)
+    for line in data.splitlines():
+        fs = str_to_ints(line)
+        l = fs[0]
+        for r in fs[1:]:
+            g[l].add(r)
+            g[r].add(l)
+    return g
+
+
+def part_1(data):
+    g = get_graph(data)
+    to_visit = [0]
+    seen = set()
+    while to_visit:
+        c = to_visit.pop()
+        if c in seen:
+            continue
+        seen.add(c)
+        for nb in g[c]:
+            to_visit.append(nb)
+    print(len(seen))
+
+
+def part_2(data):
+    g = get_graph(data)
+
+    group_count = 0
+    seen = set()
+    for c in g.keys():
+        if c in seen:
+            continue
+        group_count += 1
+        to_visit = [c]
+        while to_visit:
+            c = to_visit.pop()
+            if c in seen:
+                continue
+            seen.add(c)
+            for nb in g[c]:
+                to_visit.append(nb)
+    print(group_count)
+
+
+def main():
+    data = open(0).read().strip()
+    part_1(data)
+    part_2(data)
+
+if __name__ == "__main__":
+    main()