Queues and Stacks: Two stacks implement queues, two queues implement stacks

1. Question: Use two stacks to implement a queue. First use a stack to enter data, and then output this stack to another stack to form a first-in-first-out order for the queue.

Because PHP’s array can simulate the implementation of a stack, the code is as follows:

<?php
function StackToQueue($data)
{
	$arr=array();
	while($_t=array_pop($data)) 
	{
		array_push($arr, $_t);
	}
	return $arr;
}
$a=array();
for($i=1;$i<=5;$i++)
{
	array_push($a, $i);
}
var_dump($a);
$a=StackToQueue($a);
var_dump($a);

2, Use two queues to implement a stack. The order of the stack is mainly first in, last out. First use queue A to enter data, and then transfer the data from queue A to queue B every time the data is fetched. Only the last number is left in queue A, and then the data from queue A is dequeued to be the last element. Each time the queue data is transferred back and forth.

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The above introduces queues and stacks: two stacks implement queues, and two queues implement stacks, including aspects of the content. I hope it will be helpful to friends who are interested in PHP tutorials.