Create clone-n-ary-tree.cpp

Author: kamyu104

C++/clone-n-ary-tree.cpp

@@ -0,0 +1,49 @@
+// Time:  O(n)
+// Space: O(h)
+
+class Solution {
+public:
+    Node* cloneTree(Node* root) {
+        using RET = Node*;
+        RET result{};
+        vector<tuple<int, RET, shared_ptr<RET>, RET *>> stk = {{1, root, nullptr, &result}};
+        while (!stk.empty()) {
+            const auto [step, node, ret1, ret] = stk.back(); stk.pop_back();
+            if (step == 1) {
+                if (!node) {
+                    continue;
+                }
+                *ret = new Node(node->val);
+                for (int i = node->children.size() - 1; i >= 0; --i) {
+                    const auto& ret1 = make_shared<RET>();
+                    stk.emplace_back(2, nullptr, ret1, ret);
+                    stk.emplace_back(1, node->children[i], nullptr, ret1.get());
+                }
+            } else {
+                (*ret)->children.emplace_back(*ret1);
+            }
+        }
+        return result;
+    }
+};
+
+// Time:  O(n)
+// Space: O(h)
+class Solution2 {
+public:
+    Node* cloneTree(Node* root) {
+        return dfs(root);
+    }
+
+private:
+    Node *dfs(Node *node) {
+        if (!node) {
+            return nullptr;
+        }
+        auto copy = new Node(node->val);
+        for (const auto& child : node->children) {
+            copy->children.emplace_back(dfs(child));
+        }
+        return copy;
+    }
+};