Implement heuristic hands-free solution for day 25 that I came up with while falling asleep.

d25.py

@@ -16,7 +16,7 @@ def plot(graph):
     plt.show()
 
 
-def solve_non_hands_free(input: Input, second=False):
+def solve_non_hands_free(input: Input):
     graph = {}
     for line in input.lines():
         source, targets = line.split(":")
@@ -50,10 +50,67 @@ def solve_non_hands_free(input: Input, second=False):
 
     return len(seen) * (len(graph) - len(seen))
 
+from random import choice
+from collections import deque
+
+def solve(input: Input):
+    graph = {}
+    edges = {}
+
+    for line in input.lines():
+        src, dsts = line.split(":")
+        dsts = dsts.strip().split(" ")
+
+        if not src in graph:
+            graph[src] = []
+
+        for dst in dsts:
+            graph[src].append(dst)
+            if not dst in graph:
+                graph[dst] = []
+            graph[dst].append(src)
+
+            edge = tuple(sorted([src, dst]))
+            edges[edge] = 0
+
+    for i in range (1000):
+        first_node = choice(list(graph.keys()))
+        seen = set([first_node])
+        visit = deque([first_node])
+        while visit:
+            node = visit.popleft()
+            for nb in graph[node]:
+                if not nb in seen:
+                    seen.add(nb)
+                    visit.append(nb)
+                    edge = tuple(sorted([node, nb]))
+                    edges[edge] += 1
+    
+    most_visited = sorted(edges.items(), key=lambda t: t[1], reverse=True)[:3]
+    # for node, count in most_visited:
+    #     print(node, count)
+
+    for (a, b), _ in most_visited:
+        graph[a].remove(b)
+        graph[b].remove(a)
+
+    to_visit = [choice(list(graph.keys()))]
+    seen = set(to_visit)
+    while to_visit:
+        node = to_visit.pop()
+        for nb in graph[node]:
+            if not nb in seen:
+                seen.add(nb)
+                to_visit.append(nb)
+
+    return len(seen) * (len(graph) - len(seen))
+
 
 def main():
     DAY_INPUT = "i25.txt"
     print("Solution 1:", solve_non_hands_free(Input(DAY_INPUT)))
+    print("Solution 1:", solve(Input(DAY_INPUT)), "(hands-free)")
+
 
 
 if __name__ == "__main__":