Update 0232.用栈实现队列.md

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problems/0232.用栈实现队列.md

@@ -231,56 +231,51 @@ class MyQueue:
 Go：
 ```Go
 type MyQueue struct {
-    stack []int
-    back  []int
+	stackIn  []int //输入栈
+	stackOut []int //输出栈
 }
 
-/** Initialize your data structure here. */
 func Constructor() MyQueue {
-    return MyQueue{
-        stack: make([]int, 0),
-        back:  make([]int, 0),
-    }
+	return MyQueue{
+		stackIn:  make([]int, 0),
+		stackOut: make([]int, 0),
+	}
 }
 
-/** Push element x to the back of queue. */
+// 往输入栈做push
 func (this *MyQueue) Push(x int) {
-    for len(this.back) != 0 {
-        val := this.back[len(this.back)-1]
-        this.back = this.back[:len(this.back)-1]
-        this.stack = append(this.stack, val)
-    }
-    this.stack = append(this.stack, x)
+	this.stackIn = append(this.stackIn, x)
 }
 
-/** Removes the element from in front of queue and returns that element. */
+// 在输出栈做pop，pop时如果输出栈数据为空，需要将输入栈全部数据导入，如果非空，则可直接使用
 func (this *MyQueue) Pop() int {
-    for len(this.stack) != 0 {
-        val := this.stack[len(this.stack)-1]
-        this.stack = this.stack[:len(this.stack)-1]
-        this.back = append(this.back, val)
-    }
-    if len(this.back) == 0 {
-        return 0
-    }
-    val := this.back[len(this.back)-1]
-    this.back = this.back[:len(this.back)-1]
-    return val
+	inLen, outLen := len(this.stackIn), len(this.stackOut)
+	if outLen == 0 {
+		if inLen == 0 {
+			return -1
+		}
+		for i := inLen - 1; i >= 0; i-- {
+			this.stackOut = append(this.stackOut, this.stackIn[i])
+		}
+		this.stackIn = []int{}      //导出后清空
+		outLen = len(this.stackOut) //更新长度值
+	}
+	val := this.stackOut[outLen-1]
+	this.stackOut = this.stackOut[:outLen-1]
+	return val
 }
 
-/** Get the front element. */
 func (this *MyQueue) Peek() int {
-    val := this.Pop()
-    if val == 0 {
-        return 0
-    }
-    this.back = append(this.back, val)
-    return val
+	val := this.Pop()
+	if val == -1 {
+		return -1
+	}
+	this.stackOut = append(this.stackOut, val)
+	return val
 }
 
-/** Returns whether the queue is empty. */
 func (this *MyQueue) Empty() bool {
-    return len(this.stack) == 0 && len(this.back) == 0
+	return len(this.stackIn) == 0 && len(this.stackOut) == 0
 }
 ```