用两个堆实现队列 用两个堆实现

文章来源：https://blog.csdn.net/jsqfengbao/article/details/47089355

`
package com.xeswx.tx.management.dto.bean;

/**

• 用两个栈实现一个队列
  */

import java.util.Stack;

public class E07QueueWithTwoStacks {

/**
 * 用两个栈实现一个队列，完成两个函数appendTail和deletedHead,分别是在队列尾部插入节点
 * 和在队列头部删除节点的功能
 */
private Stack<String> stack1 = new Stack<String>();
private Stack<String> stack2 = new Stack<String>();

public void appendTail(String s) {
    stack1.push(s);
}

public String deletedHead() throws Exception {
    if (stack2.isEmpty()) {
        while (!stack1.isEmpty()) {
            stack2.push(stack1.pop());
        }
    }
    if (stack2.isEmpty()) {
        throw new Exception("队列为空，不能删除");
    }
    return stack2.pop();
}

public static void main(String[] args) throws Exception {
    E07QueueWithTwoStacks test = new E07QueueWithTwoStacks();
    test.appendTail("1");
    test.appendTail("2");
    test.deletedHead();
}

}

`
package com.xeswx.tx.management.dto.bean;

/**

• 用两个栈实现一个队列
  */

import java.util.Stack;

public class E07QueueWithTwoStacks {

/**
 * 用两个栈实现一个队列，完成两个函数appendTail和deletedHead,分别是在队列尾部插入节点
 * 和在队列头部删除节点的功能
 */
private Stack<String> stack1 = new Stack<String>();
private Stack<String> stack2 = new Stack<String>();

public void appendTail(String s) {
    stack1.push(s);
}

public String deletedHead() throws Exception {
    if (stack2.isEmpty()) {
        while (!stack1.isEmpty()) {
            stack2.push(stack1.pop());
        }
    }
    if (stack2.isEmpty()) {
        throw new Exception("队列为空，不能删除");
    }
    return stack2.pop();
}

public static void main(String[] args) throws Exception {
    E07QueueWithTwoStacks test = new E07QueueWithTwoStacks();
    test.appendTail("1");
    test.appendTail("2");
    test.deletedHead();
}

}

`

`