0589 solved.

liuyubobobo · liuyubobobo · commit 3a33a46402a0 · 2018-10-29T12:44:28.000-07:00
diff --git a/0589-N-ary-Tree-Preorder-Traversal/cpp-0589/CMakeLists.txt b/0589-N-ary-Tree-Preorder-Traversal/cpp-0589/CMakeLists.txt
@@ -0,0 +1,7 @@
+cmake_minimum_required(VERSION 3.5)
+project(cpp_0589)
+
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
+
+set(SOURCE_FILES main2.cpp)
+add_executable(cpp_0589 ${SOURCE_FILES})
diff --git a/0589-N-ary-Tree-Preorder-Traversal/cpp-0589/main.cpp b/0589-N-ary-Tree-Preorder-Traversal/cpp-0589/main.cpp
@@ -0,0 +1,54 @@
+/// Source : https://leetcode.com/problems/n-ary-tree-preorder-traversal/
+/// Author : liuyubobobo
+/// Time   : 2018-10-29
+
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+
+/// Definition for a Node.
+class Node {
+public:
+    int val;
+    vector<Node*> children;
+
+    Node() {}
+
+    Node(int _val, vector<Node*> _children) {
+        val = _val;
+        children = _children;
+    }
+};
+
+
+/// Recursion
+/// Time Complexity: O(n)
+/// Space Complexity: O(h)
+class Solution {
+public:
+    vector<int> preorder(Node* root) {
+
+        vector<int> res;
+        dfs(root, res);
+        return res;
+    }
+
+private:
+    void dfs(Node* node, vector<int>& res){
+
+        if(!node)
+            return;
+
+        res.push_back(node->val);
+        for(Node* next: node->children)
+            dfs(next, res);
+    }
+};
+
+
+int main() {
+
+    return 0;
+}
diff --git a/0589-N-ary-Tree-Preorder-Traversal/cpp-0589/main2.cpp b/0589-N-ary-Tree-Preorder-Traversal/cpp-0589/main2.cpp
@@ -0,0 +1,59 @@
+/// Source : https://leetcode.com/problems/n-ary-tree-preorder-traversal/
+/// Author : liuyubobobo
+/// Time   : 2018-10-29
+
+#include <iostream>
+#include <vector>
+#include <stack>
+
+using namespace std;
+
+
+/// Definition for a Node.
+class Node {
+public:
+    int val;
+    vector<Node*> children;
+
+    Node() {}
+
+    Node(int _val, vector<Node*> _children) {
+        val = _val;
+        children = _children;
+    }
+};
+
+
+/// Non-Recursion
+/// Using stack
+/// Time Complexity: O(n)
+/// Space Complexity: O(h)
+class Solution {
+public:
+    vector<int> preorder(Node* root) {
+
+        vector<int> res;
+        if(!root)
+            return res;
+
+        stack<pair<Node*, int>> stack;
+        stack.push(make_pair(root, 1));
+        while(!stack.empty()){
+            Node* cur = stack.top().first;
+            int step = stack.top().second;
+            stack.pop();
+
+            res.push_back(cur->val);
+            for(vector<Node*>::reverse_iterator iter = cur->children.rbegin();
+                    iter != cur->children.rend(); iter ++)
+                stack.push(make_pair(*iter, step + 1));
+        }
+        return res;
+    }
+};
+
+
+int main() {
+
+    return 0;
+}
diff --git a/readme.md b/readme.md
@@ -379,6 +379,8 @@ email: [liuyubobobo@gmail.com](mailto:liuyubobobo@gmail.com)
 | | | | | | |
 | 583 | [Delete Operation for Two Strings](https://leetcode.com/problems/delete-operation-for-two-strings/description/) | [solution](https://leetcode.com/problems/delete-operation-for-two-strings/solution/) | [C++](0583-Delete-Operation-for-Two-Strings/cpp-0583/) | | |
 | | | | | | |
+| 589 | [N-ary Tree Preorder Traversal](https://leetcode.com/problems/n-ary-tree-preorder-traversal/) | [solution](https://leetcode.com/problems/n-ary-tree-preorder-traversal/) | [C++](0589-N-ary-Tree-Preorder-Traversal/cpp-0589/) | | |
+| | | | | | |
 | 598 | [Range Addition II](https://leetcode.com/problems/range-addition-ii/description/) | | [C++](0598-Range-Addition-II/cpp-0598/) | | |
 | 599 | [Minimum Index Sum of Two Lists](https://leetcode.com/explore/learn/card/hash-table/184/comparison-with-other-data-structures/1177/) | [solution](https://leetcode.com/problems/minimum-index-sum-of-two-lists/solution/) | [C++](0599-Minimum-Index-Sum-of-Two-Lists/cpp-0599/) | | |
 | 600 | [Non-negative Integers without Consecutive Ones](https://leetcode.com/problems/non-negative-integers-without-consecutive-ones/description/) | [solution](https://leetcode.com/problems/non-negative-integers-without-consecutive-ones/solution/)<br/>[缺：Bit Manipulation]| [C++](0600-Non-negative-Integers-without-Consecutive-Ones/cpp-0600/) | | |
