diff --git a/notes/面试总结.md b/notes/面试总结.md
index cc8f1dfd..6e4dfb66 100644
--- a/notes/面试总结.md
+++ b/notes/面试总结.md
@@ -32,6 +32,8 @@
 * [27. 二叉树的镜像](#27-二叉树的镜像)
 * [28 对称的二叉树](#28-对称的二叉树)
 * [29. 顺时针打印矩阵](#29-顺时针打印矩阵)
+* [30. 包含 min 函数的栈](#30-包含-min-函数的栈)
+* [31. 栈的压入、弹出序列](#31-栈的压入弹出序列)
 
 * [参考文献](#参考文献)
 <!-- GFM-TOC -->
@@ -2185,6 +2187,111 @@ class Solution:
         return print_list
 ```
 
+# 30. 包含 min 函数的栈
+
+[NowCoder](https://www.nowcoder.com/practice/4c776177d2c04c2494f2555c9fcc1e49?tpId=13&tqId=11173&tPage=1&rp=1&ru=/ta/coding-interviews&qru=/ta/coding-interviews/question-ranking)
+
+## 题目描述
+
+定义栈的数据结构，请在该类型中实现一个能够得到栈最小元素的 min 函数。
+
+## 解题思路
+
+```java
+private Stack<Integer> dataStack = new Stack<>();
+private Stack<Integer> minStack = new Stack<>();
+
+public void push(int node) {
+    dataStack.push(node);
+    minStack.push(minStack.isEmpty() ? node : Math.min(minStack.peek(), node));
+}
+
+public void pop() {
+    dataStack.pop();
+    minStack.pop();
+}
+
+public int top() {
+    return dataStack.peek();
+}
+
+public int min() {
+    return minStack.peek();
+}
+```
+
+```python
+# -*- coding:utf-8 -*-
+class Solution:
+    def __init__(self):
+        self.stack = []
+        self.min_stack = []
+    def push(self, node):
+        # write code here
+        self.stack.append(node)
+        if not self.min_stack or node <= self.min_stack[-1]:
+            self.min_stack.append(node)
+    def pop(self):
+        # write code here
+        if self.stack[-1] == self.min_stack[-1]:
+            self.min_stack.pop()
+        self.stack.pop()
+    def top(self):
+        # write code here
+        return self.stack[-1]
+    def min(self):
+        # write code here
+        return self.min_stack[-1]
+```
+
+# 31. 栈的压入、弹出序列
+
+[NowCoder](https://www.nowcoder.com/practice/d77d11405cc7470d82554cb392585106?tpId=13&tqId=11174&tPage=1&rp=1&ru=/ta/coding-interviews&qru=/ta/coding-interviews/question-ranking)
+
+## 题目描述
+
+输入两个整数序列，第一个序列表示栈的压入顺序，请判断第二个序列是否为该栈的弹出顺序。假设压入栈的所有数字均不相等。
+
+例如序列 1,2,3,4,5 是某栈的压入顺序，序列 4,5,3,2,1 是该压栈序列对应的一个弹出序列，但 4,3,5,1,2 就不可能是该压栈序列的弹出序列。
+
+## 解题思路
+
+使用一个栈来模拟压入弹出操作。
+
+```java
+public boolean IsPopOrder(int[] pushSequence, int[] popSequence) {
+    int n = pushSequence.length;
+    Stack<Integer> stack = new Stack<>();
+    for (int pushIndex = 0, popIndex = 0; pushIndex < n; pushIndex++) {
+        stack.push(pushSequence[pushIndex]);
+        while (popIndex < n && !stack.isEmpty() 
+                && stack.peek() == popSequence[popIndex]) {
+            stack.pop();
+            popIndex++;
+        }
+    }
+    return stack.isEmpty();
+}
+```
+
+```python
+# -*- coding:utf-8 -*-
+class Solution:
+    def IsPopOrder(self, pushV, popV):
+        # write code here
+        if not pushV or len(pushV)!=len(popV):
+            return False
+        stack=[]
+        for i in pushV:
+            stack.append(i)
+            while len(stack) and stack[-1]==popV[0]:
+                stack.pop()
+                popV.pop(0)
+        if len(stack):
+            return False
+        return True
+```
+
 # 参考文献
 
 - 何海涛. 剑指 Offer[M]. 电子工业出版社, 2012.