Solve day 24 2017.

2017/d24.py

@@ -0,0 +1,35 @@
+from collections import defaultdict
+
+
+def part_1(data):
+    ports = [list(map(int, line.split("/"))) for line in data.splitlines()]
+    in_to_out = defaultdict(list)
+    for index, (i, o) in enumerate(ports):
+        in_to_out[i].append((o, index))
+        in_to_out[o].append((i, index))
+
+    max_sum = 0
+    max_len = (0, 0)
+    bs = [(0, [], 0, 0)]
+
+    while bs:
+        current_port, used, current_sum, current_len  = bs.pop()
+        max_sum = max(max_sum, current_sum)
+        max_len = max(max_len, (current_len, current_sum))
+        for out_port, index in in_to_out[current_port]:
+            if index in used:
+                continue
+            new_sum = current_sum + current_port + out_port
+            bs.append((out_port, used + [index], new_sum, current_len + 1))
+    print(max_sum)
+    print(max_len[1])
+
+
+def main():
+    with open("i24.txt") as f:
+        data = f.read()
+    part_1(data)
+
+
+if __name__ == "__main__":
+    main()

README.md

@@ -84,3 +84,5 @@ written in Python.
 - Day 21: 90:00
 - Day 22: 25:00
 - Day 23:
+- Day 24: 15:45 (48th)
+- Day 25: