Fix Non Recursive Depth First Search

Author: marcoscannabrava

graphs/depth_first_search.py

@@ -40,7 +40,7 @@ def depth_first_search(graph: Dict, start: str) -> Set[int]:
         # 1) pop last element instead of first one
         # 2) add adjacent elements to stack without exploring them
         for adj in reversed(graph[v]):
-            if adj not in explored: 
+            if adj not in explored:
                 stack.append(adj)
     return explored