Cancel the form parent node of the root node

luogu-dev · Oct 10, 2024 · 2a7b7fc · 2a7b7fc
1 parent bfafc1b
commit 2a7b7fc
Showing 1 changed file with 3 additions and 2 deletions.
diff --git a/cyaron/graph.py b/cyaron/graph.py
@@ -149,8 +149,9 @@ def to_tree(self, root = 1, *, container = list, from_weight = lambda w: None):
             if u in vis:
                 continue
             vis.add(u)
-            w = from_weight(_)
-            tree.append((fa, u) if w is None else (fa, u, w))
+            if fa != 0:
+                w = from_weight(_)
+                tree.append((fa, u) if w is None else (fa, u, w))
             for edge in self.edges[u]:
                 v, w = edge.end, edge.weight
                 if v in vis: