feat: 232.implement-queue-using-stacks add Python3 implementation (#135)

Author: ybian19

problems/232.implement-queue-using-stacks.md

@@ -16,7 +16,7 @@ Example:
 MyQueue queue = new MyQueue();
 
 queue.push(1);
-queue.push(2);  
+queue.push(2);
 queue.peek();  // returns 1
 queue.pop();   // returns 1
 queue.empty(); // returns false
@@ -64,9 +64,11 @@ push之前是这样的：
 
 ## 代码
 
-```js
+* 语言支持：JS, Python
 
+Javascript Code:
 
+```js
 /*
  * @lc app=leetcode id=232 lang=javascript
  *
@@ -132,7 +134,55 @@ MyQueue.prototype.empty = function() {
  */
 ```
 
+Python Code:
+
+```python
+class MyQueue:
+
+    def __init__(self):
+        """
+        Initialize your data structure here.
+        """
+        self.stack = []
+        self.help_stack = []
+
+    def push(self, x: int) -> None:
+        """
+        Push element x to the back of queue.
+        """
+        while self.stack:
+            self.help_stack.append(self.stack.pop())
+        self.help_stack.append(x)
+        while self.help_stack:
+            self.stack.append(self.help_stack.pop())
+
+    def pop(self) -> int:
+        """
+        Removes the element from in front of queue and returns that element.
+        """
+        return self.stack.pop()
+
+    def peek(self) -> int:
+        """
+        Get the front element.
+        """
+        return self.stack[-1]
+
+    def empty(self) -> bool:
+        """
+        Returns whether the queue is empty.
+        """
+        return not bool(self.stack)
+
+
+# Your MyQueue object will be instantiated and called as such:
+# obj = MyQueue()
+# obj.push(x)
+# param_2 = obj.pop()
+# param_3 = obj.peek()
+# param_4 = obj.empty()
+```
+
 ## 扩展
  - 类似的题目有用队列实现栈，思路是完全一样的，大家有兴趣可以试一下。
  - 栈混洗也是借助另外一个栈来完成的，从这点来看，两者有相似之处。
-