Update 30. 包含 min 函数的栈.md

题目链接改为力扣中的对应题目，题目描述和代码按该题的接口调整。

notes/30. 包含 min 函数的栈.md

@@ -2,7 +2,7 @@
 
 ## 题目链接
 
-[牛客网](https://www.nowcoder.com/practice/4c776177d2c04c2494f2555c9fcc1e49?tpId=13&tqId=11173&tPage=1&rp=1&ru=/ta/coding-interviews&qru=/ta/coding-interviews/question-ranking&from=cyc_github)
+[Leetcode](https://leetcode.cn/problems/bao-han-minhan-shu-de-zhan-lcof/)
 
 ## 题目描述
 
@@ -15,24 +15,32 @@
 <div align="center"> <img src="https://cs-notes-1256109796.cos.ap-guangzhou.myqcloud.com/image-20201104013936126.png" width="350px"> </div><br>
 
 ```java
-private Stack<Integer> dataStack = new Stack<>();
-private Stack<Integer> minStack = new Stack<>();
+class MinStack {
 
-public void push(int node) {
-    dataStack.push(node);
-    minStack.push(minStack.isEmpty() ? node : Math.min(minStack.peek(), node));
-}
+    private Stack<Integer> dataStack;
+    private Stack<Integer> minStack;
 
-public void pop() {
-    dataStack.pop();
-    minStack.pop();
-}
+    public MinStack() {
+        dataStack = new Stack<>();
+        minStack = new Stack<>();
+    }
 
-public int top() {
-    return dataStack.peek();
-}
+    public void push(int x) {
+        dataStack.push(x);
+        minStack.push(minStack.isEmpty() ? x : Math.min(minStack.peek(), x));
+    }
 
-public int min() {
-    return minStack.peek();
+    public void pop() {
+        dataStack.pop();
+        minStack.pop();
+    }
+
+    public int top() {
+        return dataStack.peek();
+    }
+
+    public int getMin() {
+        return minStack.peek();
+    }
 }
 ```