diff --git a/src/dsa/nodes.py b/src/dsa/nodes.py
index 521d24e..e8206fd 100644
--- a/src/dsa/nodes.py
+++ b/src/dsa/nodes.py
@@ -10,15 +10,10 @@ def find_last_node(nodes, edges):
 
 # Function to find all leaf nodes (nodes with no outgoing edges)
 def find_leaf_nodes(nodes: list[dict], edges: list[dict]) -> list[dict]:
-    leaf_nodes = []
-    for node in nodes:
-        is_leaf = True
-        for edge in edges:
-            if edge["source"] == node["id"]:
-                is_leaf = False
-                break
-        if is_leaf:
-            leaf_nodes.append(node)
+    # Build a set of all node ids that have outgoing edges
+    outgoing_sources = {edge["source"] for edge in edges}
+    # Nodes whose id is not in outgoing_sources are leaves
+    leaf_nodes = [node for node in nodes if node["id"] not in outgoing_sources]
     return leaf_nodes