Solve day 25. Only d21 part 2 left o.O

d25.py

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+from lib import *
+
+
+def plot(graph):
+    import networkx as nx
+    import matplotlib
+    import matplotlib.pyplot as plt
+    G = nx.Graph()
+    for node, connected_nodes in graph.items():
+        for connected_node in connected_nodes:
+            G.add_edge(node, connected_node)
+    # pos = nx.spring_layout(G, k=2.0, iterations=20)  # Adjust k as needed
+    pos = nx.shell_layout(G)
+    nx.draw(G, with_labels=True, node_color='lightblue', edge_color='gray', node_size=2000, font_size=15, font_weight='bold')
+    matplotlib.use('qtagg')
+    plt.show()
+
+
+def solve_non_hands_free(input: Input, second=False):
+    graph = {}
+    for line in input.lines():
+        source, targets = line.split(":")
+        targets = targets.strip()
+        targets = targets.split(" ")
+
+        for target in targets:
+            if not source in graph:
+                graph[source] = [target]
+            else:
+                graph[source].append(target)
+            if not target in graph:
+                graph[target] = [source]
+            else:
+                graph[target].append(source)
+
+    # plot(graph) # I used this to find the nodes that have to be removed.
+    to_remove = (("plt", "mgb"), ("jxm", "qns"), ("dbt", "tjd"))
+    for a, b in to_remove:
+        graph[a].remove(b)
+        graph[b].remove(a)
+
+    to_visit = ["plt"]
+    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)))
+
+
+if __name__ == "__main__":
+    main()