题解 | #用两个栈实现队列#

import java.util.Stack;
https://blog.csdn.net/ailunlee/article/details/85100514 参考文章
/**

• @Author: Mr.huang
• @Date: 2021/08/06/16:24
• @Description: 用两个栈实现一个队列
• /
  public class NC76 {

Stack<Integer> stackIn = new Stack<Integer>();
Stack<Integer> stackOut = new Stack<Integer>();

public static void main(String[] args) {
    NC76 nc76=new NC76();
    nc76.push(1);
    nc76.push(2);
    int pop1 = nc76.pop();
    int pop2 = nc76.pop();
    System.out.println(pop1);
    System.out.println(pop2);
}


public  void push(int node) {
    stackIn.push(node);
}

/**
 *出栈的时候要考虑到栈为空的情况
 * @return
 */
public int pop() {
    Integer pop=null;
    if (!stackOut.isEmpty()){
        pop = stackOut.pop();
        return pop;
    }else {
        if (stackIn.isEmpty()){
            return -1;
        }else{
        while (!stackIn.isEmpty()){
            Integer out = stackIn.pop();
            stackOut.push(out);
          }
            pop = stackOut.pop();
        }
        return pop;
    }
}

}