leetcode-go/leetcode/easy/225.implement-stack-using-queues.go

type MyStack struct {
    Peek Queue
	Body Queue
}


/** Initialize your data structure here. */
func Constructor() MyStack {
	return MyStack{make([]int, 0), make([]int, 0)}
}


/** Push element x onto stack. */
func (this *MyStack) Push(x int)  {
	this.Peek.Enqueue(x)
	if this.Peek.Size() == 2 {
		this.Body.Enqueue(this.Peek.Dequeue())
	}
}


/** Removes the element on top of the stack and returns that element. */
func (this *MyStack) Pop() int {
	n := this.Body.Size()
	top := this.Peek.Dequeue()
	for i := 0; i < n-1; i++ {
		this.Peek.Enqueue(this.Body.Dequeue())
	}
	this.Peek, this.Body = this.Body, this.Peek
	return top
}


/** Get the top element. */
func (this *MyStack) Top() int {
	return this.Peek.Front()
}


/** Returns whether the stack is empty. */
func (this *MyStack) Empty() bool {
	return this.Peek.Empty()
}


/**
 * Your MyStack object will be instantiated and called as such:
 * obj := Constructor();
 * obj.Push(x);
 * param_2 := obj.Pop();
 * param_3 := obj.Top();
 * param_4 := obj.Empty();
 */


// Queue ...
type Queue []int


// Dequeue ...
func (q *Queue) Dequeue() int {
	front := (*q)[0]
	*q = (*q)[1:]
	return front
}


// Enqueue ...
func (q *Queue) Enqueue(x int) {
	*q = append(*q, x)
}


// Front ...
func (q Queue) Front() int {
	return q[0]
}


// Size ...
func (q Queue) Size() int {
	return len(q)
}


// Empty ...
func (q Queue) Empty() bool {
	return len(q) == 0
}