LeetCode，Go 实现最小栈

type MinStack struct {
    stack []int
    minStack []int
}

/** initialize your data structure here. */
func Constructor() MinStack {
    return MinStack{
        stack: []int{},
        minStack: []int{math.MaxInt64},
    }
}

func (this *MinStack) Push(val int)  {
    this.stack = append(this.stack, val)
    top := this.minStack[len(this.minStack)-1]
    this.minStack = append(this.minStack, min(val, top))
}

func (this *MinStack) Pop()  {
    this.stack = this.stack[:len(this.stack)-1]
    this.minStack = this.minStack[:len(this.minStack)-1]
}

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

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

func min(x, y int) int {
    if x < y {
        return x
    }
    return y
}

/**
 * Your MinStack object will be instantiated and called as such:
 * obj := Constructor();
 * obj.Push(val);
 * obj.Pop();
 * param_3 := obj.Top();
 * param_4 := obj.GetMin();
 */