From 55ce51443716f5e6091bd57da982070510e9784d Mon Sep 17 00:00:00 2001
From: youngyangyang04 <826123027@qq.com>
Date: Wed, 29 Jul 2020 09:47:54 +0800
Subject: [PATCH] Update

---
 README.md                                 |  2 +
 problems/0094.二叉树的中序遍历.md | 28 +++++++++++++
 problems/0144.二叉树的前序遍历.md | 51 +++++++++++++++++++++++
 3 files changed, 81 insertions(+)
 create mode 100644 problems/0094.二叉树的中序遍历.md
 create mode 100644 problems/0144.二叉树的前序遍历.md

diff --git a/README.md b/README.md
index 97b20ee9..280d91a1 100644
--- a/README.md
+++ b/README.md
@@ -34,7 +34,9 @@
 |[0053.最大子序和](https://github.com/youngyangyang04/leetcode/blob/master/problems/0053.最大子序和.md) |数组 |简单|**暴力** **贪心** 动态规划 分治|
 |[0059.螺旋矩阵II](https://github.com/youngyangyang04/leetcode/blob/master/problems/0059.螺旋矩阵II.md) |数组 |中等|**模拟**|
 |[0083.删除排序链表中的重复元素](https://github.com/youngyangyang04/leetcode/blob/master/problems/0083.删除排序链表中的重复元素.md) |链表 |简单|**模拟**|
+|[0094.二叉树的中序遍历](https://github.com/youngyangyang04/leetcode/blob/master/problems/0094.二叉树的中序遍历.md) |树 |中等|**递归** **栈**|
 |[0142.环形链表II](https://github.com/youngyangyang04/leetcode/blob/master/problems/0142.环形链表II.md) |链表 |中等|**快慢指针/双指针**|
+|[0144.二叉树的前序遍历](https://github.com/youngyangyang04/leetcode/blob/master/problems/0144.二叉树的前序遍历.md) |树 |中等|**递归** **栈**|
 |[0151.翻转字符串里的单词](https://github.com/youngyangyang04/leetcode/blob/master/problems/0151.翻转字符串里的单词.md) |字符串 |中等|**模拟/双指针**|
 |[0155.最小栈](https://github.com/youngyangyang04/leetcode/blob/master/problems/0155.最小栈.md) |栈 |简单|**栈**|
 |[0202.快乐数](https://github.com/youngyangyang04/leetcode/blob/master/problems/0202.快乐数.md) |哈希表 |简单|**哈希**|
diff --git a/problems/0094.二叉树的中序遍历.md b/problems/0094.二叉树的中序遍历.md
new file mode 100644
index 00000000..118c7c27
--- /dev/null
+++ b/problems/0094.二叉树的中序遍历.md
@@ -0,0 +1,28 @@
+## 题目地址 
+https://leetcode-cn.com/problems/binary-tree-inorder-traversal/
+
+## 思路 
+
+
+## C++代码
+
+递归
+```
+class Solution {
+public:
+    void traversal(TreeNode* root, vector<int>& vec) {
+        if (root == NULL) return;
+        traversal(root->left, vec);
+        vec.push_back(root->val);
+        traversal(root->right, vec);
+    }
+    vector<int> inorderTraversal(TreeNode* root) {
+        vector<int> result;
+        traversal(root, result);
+        return result;
+    }
+};
+```
+
+
+> 更多算法干货文章持续更新，可以微信搜索「代码随想录」第一时间围观，关注后，回复「Java」「C++」 「python」「简历模板」「数据结构与算法」等等，就可以获得我多年整理的学习资料。
diff --git a/problems/0144.二叉树的前序遍历.md b/problems/0144.二叉树的前序遍历.md
new file mode 100644
index 00000000..bfe610b4
--- /dev/null
+++ b/problems/0144.二叉树的前序遍历.md
@@ -0,0 +1,51 @@
+## 题目地址 
+https://leetcode-cn.com/problems/binary-tree-preorder-traversal/
+
+## 思路 
+
+实现树的遍历有使用递归和使用栈两种思路
+
+## C++代码
+
+递归
+```
+class Solution {
+public:
+    void traversal(TreeNode* root, vector<int>& vec) {
+        if (root == NULL) return;
+        vec.push_back(root->val);
+        traversal(root->left, vec);
+        traversal(root->right, vec);
+    }
+    vector<int> preorderTraversal(TreeNode* root) {
+        vector<int> result;
+        traversal(root, result);
+        return result;
+    }
+};
+```
+
+栈
+```
+class Solution {
+public:
+    vector<int> preorderTraversal(TreeNode* root) {
+        stack<TreeNode*> st;
+        vector<int> result;
+        st.push(root);
+        while (!st.empty()) {
+            TreeNode* node = st.top();
+            st.pop();
+            if (node != NULL) result.push_back(node->val);
+            else continue;
+            st.push(node->right);
+            st.push(node->left);
+        }
+        return result;
+    }
+};
+```
+
+
+
+> 更过算法干货文章持续更新，可以微信搜索「代码随想录」第一时间围观，关注后，回复「Java」「C++」 「python」「简历模板」「数据结构与算法」等等，就可以获得我多年整理的学习资料。