feat: 修改232题中Java写法及命名

命名更易理解，写法更加简洁

Author: joeCarf

problems/0232.用栈实现队列.md

@@ -130,43 +130,42 @@ Java：
 ```java
 class MyQueue {
 
-    Stack<Integer> stack1;
-    Stack<Integer> stack2;
+    Stack<Integer> stackIn;
+    Stack<Integer> stackOut;
 
     /** Initialize your data structure here. */
     public MyQueue() {
-        stack1 = new Stack<>(); // 负责进栈
-        stack2 = new Stack<>(); // 负责出栈
+        stackIn = new Stack<>(); // 负责进栈
+        stackOut = new Stack<>(); // 负责出栈
     }
     
     /** Push element x to the back of queue. */
     public void push(int x) {
-        stack1.push(x);
+        stackIn.push(x);
     }
     
     /** Removes the element from in front of queue and returns that element. */
     public int pop() {    
-        dumpStack1();
-        return stack2.pop();
+        dumpstackIn();
+        return stackOut.pop();
     }
     
     /** Get the front element. */
     public int peek() {
-        dumpStack1();
-        return stack2.peek();
+        dumpstackIn();
+        return stackOut.peek();
     }
     
     /** Returns whether the queue is empty. */
     public boolean empty() {
-        return stack1.isEmpty() && stack2.isEmpty();
+        return stackIn.isEmpty() && stackOut.isEmpty();
     }
 
-    // 如果stack2为空，那么将stack1中的元素全部放到stack2中
-    private void dumpStack1(){
-        if (stack2.isEmpty()){
-            while (!stack1.isEmpty()){
-                stack2.push(stack1.pop());
-            }
+    // 如果stackOut为空，那么将stackIn中的元素全部放到stackOut中
+    private void dumpstackIn(){
+        if (!stackOut.isEmpty()) return; 
+        while (!stackIn.isEmpty()){
+                stackOut.push(stackIn.pop());
         }
     }
 }
@@ -302,8 +301,8 @@ func (this *MyQueue) Empty() bool {
  * Initialize your data structure here.
  */
 var MyQueue = function() {
-    this.stack1 = [];
-    this.stack2 = [];
+    this.stackIn = [];
+    this.stackOut = [];
 };
 
 /**
@@ -312,22 +311,22 @@ var MyQueue = function() {
  * @return {void}
  */
 MyQueue.prototype.push = function(x) {
-    this.stack1.push(x);
+    this.stackIn.push(x);
 };
 
 /**
  * Removes the element from in front of queue and returns that element.
  * @return {number}
  */
 MyQueue.prototype.pop = function() {
-    const size = this.stack2.length;
+    const size = this.stackOut.length;
     if(size) {
-        return this.stack2.pop();
+        return this.stackOut.pop();
     }
-    while(this.stack1.length) {
-        this.stack2.push(this.stack1.pop());
+    while(this.stackIn.length) {
+        this.stackOut.push(this.stackIn.pop());
     }
-    return this.stack2.pop();
+    return this.stackOut.pop();
 };
 
 /**
@@ -336,7 +335,7 @@ MyQueue.prototype.pop = function() {
  */
 MyQueue.prototype.peek = function() {
     const x = this.pop();
-    this.stack2.push(x);
+    this.stackOut.push(x);
     return x;
 };
 
@@ -345,7 +344,7 @@ MyQueue.prototype.peek = function() {
  * @return {boolean}
  */
 MyQueue.prototype.empty = function() {
-    return !this.stack1.length && !this.stack2.length
+    return !this.stackIn.length && !this.stackOut.length
 };
  ```
 
@@ -419,9 +418,9 @@ void myQueuePush(MyQueue* obj, int x) {
 }
 
 /*
-1.若输出栈为空且当第一个栈中有元素（stackInTop>0时），将第一个栈中元素复制到第二个栈中（stack2[stackTop2++] = stack1[--stackTop1])
+1.若输出栈为空且当第一个栈中有元素（stackInTop>0时），将第一个栈中元素复制到第二个栈中（stackOut[stackTop2++] = stackIn[--stackTop1])
 2.将栈顶元素保存
-3.当stackTop2>0时，将第二个栈中元素复制到第一个栈中(stack1[stackTop1++] = stack2[--stackTop2])
+3.当stackTop2>0时，将第二个栈中元素复制到第一个栈中(stackIn[stackTop1++] = stackOut[--stackTop2])
 */
 int myQueuePop(MyQueue* obj) {
     //优化：复制栈顶指针，减少对内存的访问次数