| Valid Parentheses | 20 | Easy | https://blog.codeand.fun/2017/09/24/Valid-Parentheses/ | 可以建一个右括号到左括号的map来使代码更加简洁 |
| Simplify Path | 71 | Medium | https://blog.codeand.fun/2019/03/02/Simplify-Path/ | 用FSM的思想也可以解，可以用stringstream和getline进行字符串分割 |
| Binary Tree Inorder Traversal | 94 | Medium | https://blog.codeand.fun/2020/03/24/Binary-Tree-Preorder-Inorder-Postorder-Traversal/ | 递归、栈、莫里斯遍历 |
| Binary Tree Zigzag Level Order Traversal | 103 | Medium | https://blog.codeand.fun/2018/02/11/Binary-Tree-Zigzag-Level-Order-Traversal/ | 用栈来模拟，可以避免逆序操作 |
| Binary Tree Preorder Traversal | 144 | Medium | https://blog.codeand.fun/2020/03/24/Binary-Tree-Preorder-Inorder-Postorder-Traversal/ | 递归、栈、莫里斯遍历 |
| Binary Tree Postorder Traversal | 145 | Medium | https://blog.codeand.fun/2020/03/24/Binary-Tree-Preorder-Inorder-Postorder-Traversal/ | function对象+lambda表达式可以减少代码冗余。 |
| Evaluate Reverse Polish Notation | 150 | Medium | https://blog.codeand.fun/2020/03/31/Evaluate-Reverse-Polish-Notation/ | |
| Binary Search Tree Iterator | 173 | Medium | https://blog.codeand.fun/2020/03/31/Binary-Search-Tree-Iterator/ | 可以用递归、栈和莫里斯遍历来实现中序遍历 |
| Verify Preorder Serialization of a Binary Tree | 331 | Medium | https://blog.codeand.fun/2018/02/19/Verify-Preorder-Serialization-of-a-Binary-Tree/ | ??这道题和栈好像没有关系啊，不用栈去想反而更简单更快 |
| Flatten Nested List Iterator | 341 | Medium | https://blog.codeand.fun/2018/02/14/Flatten-Nested-List-Iterator/ | 似乎很多用递归能解（但是比较复杂）的题目都可以用栈来简化。同时，用iterator可以有效减少内存消耗。 |
| Decode String | 394 | Medium | | |
