Add week 9 solutions: cloneGraph

Author: yolophg

clone-graph/yolophg.js

@@ -0,0 +1,33 @@
+// Time Complexity: O(N + E) Node + Edge
+// Space Complexity: O(N + E)
+
+var cloneGraph = function (node) {
+  // to keep track of all the nodes that have already been copied
+  const map = new Map();
+
+  // helper to perform the deep copy
+  const dfs = (currentNode) => {
+    if (!currentNode) return null;
+
+    // if the node has already been copied, return the copied one
+    if (map.has(currentNode)) return map.get(currentNode);
+
+    // create a new node with the current node's value
+    const newNode = new Node(currentNode.val);
+
+    // store this new node in the map
+    map.set(currentNode, newNode);
+
+    // iterate through each neighbor of the current node
+    for (const neighbor of currentNode.neighbors) {
+      // clone the neighbors and add them to the new node's neighbors
+      newNode.neighbors.push(dfs(neighbor));
+    }
+
+    // return the newly created node
+    return newNode;
+  };
+
+  // start the deep copy from the given node
+  return dfs(node);
+};