package leetcode

// MinStack define
type MinStack struct {
	elements, min []int
	l             int
}

/** initialize your data structure here. */

// Constructor155 define
func Constructor155() MinStack {
	return MinStack{make([]int, 0), make([]int, 0), 0}
}

// Push define
func (this *MinStack) Push(x int) {
	this.elements = append(this.elements, x)
	if this.l == 0 {
		this.min = append(this.min, x)
	} else {
		min := this.GetMin()
		if x < min {
			this.min = append(this.min, x)
		} else {
			this.min = append(this.min, min)
		}
	}
	this.l++
}

func (this *MinStack) Pop() {
	this.l--
	this.min = this.min[:this.l]
	this.elements = this.elements[:this.l]
}

func (this *MinStack) Top() int {
	return this.elements[this.l-1]
}

func (this *MinStack) GetMin() int {
	return this.min[this.l-1]
}