Queue and stack: two stacks implement queues and two queues implement stacks

: This article mainly introduces queues and stacks: two stacks implement queues and two queues implement stacks. if you are interested in PHP tutorials, refer to them. 1. Question: use two stacks to implement a queue. First input data into one stack and then output the stack to another stack to form the first-in-first-out order of the queue.

Because PHP arrays can simulate stack implementation, the code is as follows:

 2. implement a stack using two queues. The stack sequence is advanced and backward. First input data in queue A, and then transfer the data in queue A to queue B each time the data is retrieved. only the last number is left in queue, then, the data in queue A is the last element. Data is transferred back and forth every time.
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The above introduces the queue and stack: two stacks implement the queue, two queues implement the stack, including the content, hope to be helpful to friends who are interested in PHP tutorials.