两个队列生成一个栈

阳光穿透心脏的1/2处 2022-05-26 06:26 145阅读 0赞

<table> 
 <tbody> 
 <tr> 
 <td>package&nbsp;队列;&nbsp;/**&nbsp;* 两个队列实现一个栈&nbsp;* &nbsp;* 思路：队列1和队列2在任意时刻至少有一个为空，即如果有元素，所有元素只能在一个队列中。当有元素需要插入时，将元素插入到&nbsp;*&nbsp;空队列中，并将另一非空队列的所有元素全部转移到该队列中，于是，插入的元素添加到了对列的最前面&nbsp;* &nbsp;* @author&nbsp;Administrator&nbsp;*&nbsp;*/public&nbsp;class&nbsp;Stack { 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 Queue queue1&nbsp;= new&nbsp;Queue(); 
 Queue queue2&nbsp;= new&nbsp;Queue(); 
 
 /** 
 &nbsp;* 判断非空 
 &nbsp;* @return 
 &nbsp;*/ 
 public&nbsp;boolean&nbsp;isEmpty(){ 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 return&nbsp;queue1.isEmpty() &amp;&amp; queue2.isEmpty(); 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 } 
 
 /** 
 &nbsp;* 添加元素 
 &nbsp;*/ 
 public&nbsp;void&nbsp;push(int&nbsp;data){ 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 if(queue1.isEmpty()){ 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 queue1.push(data); 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 while(!queue2.isEmpty()){ 
 </blockquote> 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 queue1.push(queue2.pop()); 
 </blockquote> 
 </blockquote> 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 } 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 }else{ 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 queue2.push(data); 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 while(!queue1.isEmpty()){ 
 </blockquote> 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 queue2.push(queue1.pop()); 
 </blockquote> 
 </blockquote> 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 } 
 </blockquote> 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 } 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 } 
 
 /** 
 &nbsp;* 从栈取元素 
 &nbsp;* @return 
 &nbsp;*/ 
 public&nbsp;Integer pop(){ 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 if(queue1.isEmpty()&amp;&amp;queue2.isEmpty()){ 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 return&nbsp;null; 
 </blockquote> 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 } 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 if(!queue1.isEmpty()){ 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 return&nbsp;queue1.pop(); 
 </blockquote> 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 }else{ 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 return&nbsp;queue2.pop(); 
 </blockquote> 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 } 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 } 
 
 /** 
 &nbsp;* 取峰值 
 &nbsp;* @return 
 &nbsp;*/ 
 public&nbsp;Integer peek(){ 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 if(queue1.isEmpty()&amp;&amp;queue2.isEmpty()){ 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 return&nbsp;null; 
 </blockquote> 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 } 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 if(!queue1.isEmpty()){ 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 return&nbsp;queue1.peek(); 
 </blockquote> 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 }else{ 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 return&nbsp;queue2.peek(); 
 </blockquote> 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 } 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 } 
 
 /** 
 &nbsp;* 主函数 
 &nbsp;* @param&nbsp;args 
 &nbsp;*/ 
 public&nbsp;static&nbsp;void&nbsp;main(String[] args) { 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 Stack stack&nbsp;= new&nbsp;Stack(); 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 stack.push(1); 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 stack.push(2); 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 stack.push(3); 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 stack.push(4); 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 while(!stack.isEmpty()){ 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 System.out.println(stack.pop()); 
 </blockquote> 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 } 
 </blockquote> 
 </blockquote> 
 <blockquote style="margin:0 0 0 40px;border:none;padding:0px;"> 
 } 
 </blockquote>}</td> 
 </tr> 
 </tbody> 
</table>