feat: add python and java solutions to leetcode problem: No.0155

Author: yanglbme

README.md

@@ -77,6 +77,7 @@
 ### 栈和队列
 
 1. [有效的括号](/solution/0000-0099/0020.Valid%20Parentheses/README.md)
+1. [最小栈](/solution/0100-0199/0155.Min%20Stack/README.md)
 1. [用栈实现队列](/solution/0200-0299/0232.Implement%20Queue%20using%20Stacks/README.md)
 1. [用队列实现栈](/solution/0200-0299/0225.Implement%20Stack%20using%20Queues/README.md)
 

README_EN.md

@@ -72,6 +72,7 @@ Complete solutions to [LeetCode](https://leetcode-cn.com/problemset/all/), [LCOF
 ### Stack & Queue
 
 1. [Valid Parentheses](/solution/0000-0099/0020.Valid%20Parentheses/README_EN.md)
+1. [Min Stack](/solution/0100-0199/0155.Min%20Stack/README_EN.md)
 1. [Implement Queue using Stacks](/solution/0200-0299/0232.Implement%20Queue%20using%20Stacks/README_EN.md)
 1. [Implement Stack using Queues](/solution/0200-0299/0225.Implement%20Stack%20using%20Queues/README_EN.md)
 

solution/0100-0199/0155.Min Stack/README.md

@@ -37,15 +37,84 @@ minStack.getMin();   --> 返回 -2.
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```python
+class MinStack:
 
+    def __init__(self):
+        """
+        initialize your data structure here.
+        """
+        self.s = []
+        self.helper = []
+
+
+    def push(self, x: int) -> None:
+        self.s.append(x)
+        element = x if not self.helper or x < self.helper[-1] else self.helper[-1]
+        self.helper.append(element)
+
+    def pop(self) -> None:
+        self.s.pop()
+        self.helper.pop()
+
+    def top(self) -> int:
+        return self.s[-1]
+
+    def getMin(self) -> int:
+        return self.helper[-1]
+
+
+# Your MinStack object will be instantiated and called as such:
+# obj = MinStack()
+# obj.push(x)
+# obj.pop()
+# param_3 = obj.top()
+# param_4 = obj.getMin()
 ```
 
 ### **Java**
 
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```java
-
+class MinStack {
+
+    private Deque<Integer> s;
+    private Deque<Integer> helper;
+
+    /** initialize your data structure here. */
+    public MinStack() {
+        s = new ArrayDeque<>();
+        helper = new ArrayDeque<>();
+    }
+
+    public void push(int x) {
+        s.push(x);
+        int element = helper.isEmpty() || x < helper.peek() ? x : helper.peek();
+        helper.push(element);
+    }
+
+    public void pop() {
+        s.pop();
+        helper.pop();
+    }
+
+    public int top() {
+        return s.peek();
+    }
+
+    public int getMin() {
+        return helper.peek();
+    }
+}
+
+/**
+ * Your MinStack object will be instantiated and called as such:
+ * MinStack obj = new MinStack();
+ * obj.push(x);
+ * obj.pop();
+ * int param_3 = obj.top();
+ * int param_4 = obj.getMin();
+ */
 ```
 
 ### **...**

solution/0100-0199/0155.Min Stack/README_EN.md

@@ -7,15 +7,10 @@
 <p>Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.</p>
 
 <ul>
-
     <li>push(x) -- Push element x onto stack.</li>
-
     <li>pop() -- Removes the element on top of the stack.</li>
-
     <li>top() -- Get the top element.</li>
-
     <li>getMin() -- Retrieve the minimum element in the stack.</li>
-
 </ul>
 
 <p>&nbsp;</p>
@@ -51,13 +46,82 @@ minStack.getMin();   --&gt; Returns -2.
 ### **Python3**
 
 ```python
+class MinStack:
+
+    def __init__(self):
+        """
+        initialize your data structure here.
+        """
+        self.s = []
+        self.helper = []
+
 
+    def push(self, x: int) -> None:
+        self.s.append(x)
+        element = x if not self.helper or x < self.helper[-1] else self.helper[-1]
+        self.helper.append(element)
+
+    def pop(self) -> None:
+        self.s.pop()
+        self.helper.pop()
+
+    def top(self) -> int:
+        return self.s[-1]
+
+    def getMin(self) -> int:
+        return self.helper[-1]
+
+
+# Your MinStack object will be instantiated and called as such:
+# obj = MinStack()
+# obj.push(x)
+# obj.pop()
+# param_3 = obj.top()
+# param_4 = obj.getMin()
 ```
 
 ### **Java**
 
 ```java
-
+class MinStack {
+
+    private Deque<Integer> s;
+    private Deque<Integer> helper;
+
+    /** initialize your data structure here. */
+    public MinStack() {
+        s = new ArrayDeque<>();
+        helper = new ArrayDeque<>();
+    }
+
+    public void push(int x) {
+        s.push(x);
+        int element = helper.isEmpty() || x < helper.peek() ? x : helper.peek();
+        helper.push(element);
+    }
+
+    public void pop() {
+        s.pop();
+        helper.pop();
+    }
+
+    public int top() {
+        return s.peek();
+    }
+
+    public int getMin() {
+        return helper.peek();
+    }
+}
+
+/**
+ * Your MinStack object will be instantiated and called as such:
+ * MinStack obj = new MinStack();
+ * obj.push(x);
+ * obj.pop();
+ * int param_3 = obj.top();
+ * int param_4 = obj.getMin();
+ */
 ```
 
 ### **...**

solution/0100-0199/0155.Min Stack/Solution.java

@@ -1,30 +1,31 @@
 class MinStack {
-    
-    private Stack<Integer> stack;
-    private Stack<Integer> help;
+
+    private Deque<Integer> s;
+    private Deque<Integer> helper;
 
     /** initialize your data structure here. */
     public MinStack() {
-        stack = new Stack<>();
-        help = new Stack<>();
+        s = new ArrayDeque<>();
+        helper = new ArrayDeque<>();
     }
 
     public void push(int x) {
-        stack.push(x);
-        help.push(help.isEmpty() || help.peek() >= x ? x : help.peek());
+        s.push(x);
+        int element = helper.isEmpty() || x < helper.peek() ? x : helper.peek();
+        helper.push(element);
     }
 
     public void pop() {
-        stack.pop();
-        help.pop();
+        s.pop();
+        helper.pop();
     }
 
     public int top() {
-        return stack.peek();
+        return s.peek();
     }
 
     public int getMin() {
-        return help.peek();
+        return helper.peek();
     }
 }
 

solution/0100-0199/0155.Min Stack/Solution.py

@@ -0,0 +1,32 @@
+class MinStack:
+
+    def __init__(self):
+        """
+        initialize your data structure here.
+        """
+        self.s = []
+        self.helper = []
+
+
+    def push(self, x: int) -> None:
+        self.s.append(x)
+        element = x if not self.helper or x < self.helper[-1] else self.helper[-1]
+        self.helper.append(element)
+
+    def pop(self) -> None:
+        self.s.pop()
+        self.helper.pop()
+
+    def top(self) -> int:
+        return self.s[-1]
+
+    def getMin(self) -> int:
+        return self.helper[-1]
+
+
+# Your MinStack object will be instantiated and called as such:
+# obj = MinStack()
+# obj.push(x)
+# obj.pop()
+# param_3 = obj.top()
+# param_4 = obj.getMin()