![\"\"](\"https:\/\/prepbytes-misc-images.s3.ap-south-1.amazonaws.com\/assets\/1674626627740-Implementing%20Queue%20using%20Stacks.jpg\")
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In this tutorial, we will talk about a famous data structure problem \u201cimplement queue using stack\u201d. Firstly, we will understand what stack and queue in data structure, then we will discuss how to implement queue using stack. Let\u2019s take small steps and discuss how to implement queue using stack.<\/p>\n
Queue: <\/strong>A Queue is a linear data structure. Queue follows the FIFO rule i.e. First in First out. In other words we can say the element that goes in first is the element that comes out first. Stack follows the principle of LIFO<\/strong> (Last in First out) i.e. element which is inserted at last will be removed first. The operation for insertion of elements in stack is known as Push operation and the operation for deletion of element in stack is known as Pop operation.<\/p>\n We can implement a queue by using two stacks. This method just makes sure that the oldest entered element is always at the top of s1. So, the dequeue operation just pops the element from s1. To put the element at top of s1 we\u2019ll use s2.<\/p>\n Code Implementation<\/strong>
\nFor Example A ticket Queue outside a cinema hall where the person enters the queue first will get the ticket first.<\/p>\nBasic Operations of Queue:<\/h3>\n
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![\"\"](\"https:\/\/prepbytes-misc-images.s3.ap-south-1.amazonaws.com\/assets\/1656308868826-Image-01.png\")
<\/p>\nStack<\/h3>\n
![\"\"](\"https:\/\/prepbytes-misc-images.s3.ap-south-1.amazonaws.com\/assets\/1656499770090-Image-02%20%282%29.png\")
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\nLet queue be q and stack be s1 and s2:<\/p>\nApproach 1: To Implement Queue using Stack by Making Enqueue Operation Costly:<\/h3>\n
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