剑指 Offer 04. 用两个栈实现队列

package main

var stack1 [] int
var stack2 [] int

func Push(node int) {
    stack1 = append(stack1, node)
}

func Pop() int{
    res := -1
    if len(stack2) > 0 {
        res = stack2[0]
        stack2 = stack2[1:]
    } else {
        if len(stack1) != 0 {
            res = stack1[0]
            stack2 = stack1[1:]
            stack1 = stack1[:0]
        }
    }
    
    return res
}