solve: cloneGraph

Author: GaggleHelena

clone-graph/yolophg.py

@@ -0,0 +1,28 @@
+# Time Complexity: O(N + E) - visit each node once and for each node, we iterate through its neighbors O(E).
+# Space Complexity: O(N) - store a copy of each node in the hashmap O(N).
+
+class Solution:
+    def cloneGraph(self, node):
+        if node is None:
+            return None
+    
+        # dictionary to keep track of cloned nodes (original -> clone)
+        mp = {} 
+
+        def clone(node):
+            if node in mp:
+                # if the node has already been cloned, return the copy
+                return mp[node]  
+
+            # create a new node with the same value
+            cpy = Node(node.val)  
+            # store it in the map so don't clone it again
+            mp[node] = cpy  
+
+            # clone all neighbors and add them to the new node's neighbors list
+            for n in node.neighbors:
+                cpy.neighbors.append(clone(n))
+
+            return cpy
+
+        return clone(node)