ProblemSubmissionsLeaderboardDiscussionsA queue is an abstract data type that maintains the order in which elements were added to it, allowing the oldest elements to be removed from the front and new elements to be added to the rear. This is called a First-In-First-Out (FIFO) data structure because the first element added to the queue (i.e., the one that has been waiting the longest) is always the first one to be removed.A basic queue has the following operations:Enqueue: add a new element to the end of the queue.Dequeue: remove the element from the front of the queue and return it.In this challenge, you must first implement a queue using two stacks. Then process queries, where each query is one of the following types:1 x: Enqueue element into the end of the queue.2: Dequeue the element at the front of the queue.3: Print the element at the front of the queue.Input FormatThe first line contains a single integer, , denoting the number of queries.Each line of the subsequent lines contains a single query in the form described in the problem statement above. All three queries start with an integer denoting the query , but only query is followed by an additional space-separated value, , denoting the value to be enqueued.ConstraintsIt is guaranteed that a valid answer always exists for each query of type .Output FormatFor each query of type , print the value of the element at the front of the queue on a new line.Sample InputSTDIN Function----- --------10 q = 10 (number of queries)1 42 1st query, enqueue 422 dequeue front element1 14 enqueue 423 print the front element1 28 enqueue 283 print the front element1 60 enqueue 601 78 enqueue 782 dequeue front element2 dequeue front elementSample Output1414ExplanationPerform the following sequence of actions:Enqueue ; .Dequeue the value at the head of the queue, ; .Enqueue ; .Print the value at the head of the queue, ; .Enqueue ; .Print the value at the head of the queue, ; .Enqueue ; .Enqueue ; .Dequeue the value at the head of the queue, ; .Dequeue the value at the head of the queue, ; .
Question
ProblemSubmissionsLeaderboardDiscussionsA queue is an abstract data type that maintains the order in which elements were added to it, allowing the oldest elements to be removed from the front and new elements to be added to the rear. This is called a First-In-First-Out (FIFO) data structure because the first element added to the queue (i.e., the one that has been waiting the longest) is always the first one to be removed.A basic queue has the following operations:Enqueue: add a new element to the end of the queue.Dequeue: remove the element from the front of the queue and return it.In this challenge, you must first implement a queue using two stacks. Then process queries, where each query is one of the following types:1 x: Enqueue element into the end of the queue.2: Dequeue the element at the front of the queue.3: Print the element at the front of the queue.Input FormatThe first line contains a single integer, , denoting the number of queries.Each line of the subsequent lines contains a single query in the form described in the problem statement above. All three queries start with an integer denoting the query , but only query is followed by an additional space-separated value, , denoting the value to be enqueued.ConstraintsIt is guaranteed that a valid answer always exists for each query of type .Output FormatFor each query of type , print the value of the element at the front of the queue on a new line.Sample InputSTDIN Function----- --------10 q = 10 (number of queries)1 42 1st query, enqueue 422 dequeue front element1 14 enqueue 423 print the front element1 28 enqueue 283 print the front element1 60 enqueue 601 78 enqueue 782 dequeue front element2 dequeue front elementSample Output1414ExplanationPerform the following sequence of actions:Enqueue ; .Dequeue the value at the head of the queue, ; .Enqueue ; .Print the value at the head of the queue, ; .Enqueue ; .Print the value at the head of the queue, ; .Enqueue ; .Enqueue ; .Dequeue the value at the head of the queue, ; .Dequeue the value at the head of the queue, ; .
Solution
The problem is asking to implement a queue using two stacks. A queue is a First-In-First-Out (FIFO) data structure. This means that the first element that is added to the queue is the first one to be removed.
The operations that need to be implemented are:
- Enqueue: This operation adds a new element to the end of the queue.
- Dequeue: This operation removes the element from the front of the queue and returns it.
- Print: This operation prints the element at the front of the queue.
The input will be a series of queries. Each query will be one of the three operations mentioned above. The first line of the input will be a single integer, denoting the number of queries. Each of the subsequent lines will contain a single query. All three queries start with an integer denoting the query type. Only query type 1 is followed by an additional space-separated value, denoting the value to be enqueued.
The output should be the result of each query of type 3. For each query of type 3, print the value of the element at the front of the queue on a new line.
The problem also provides a sample input and output to better understand how the queue operations work.
For example, if the input is:
10 1 42 2 1 14 3 1 28 3 1 60 1 78 2 2
The output will be:
14 14
This is because the sequence of operations is as follows:
- Enqueue 42; queue = [42].
- Dequeue; queue = [].
- Enqueue 14; queue = [14].
- Print; output = 14.
- Enqueue 28; queue = [14, 28].
- Print; output = 14.
- Enqueue 60; queue = [14, 28, 60].
- Enqueue 78; queue = [14, 28, 60, 78].
- Dequeue; queue = [28, 60, 78].
- Dequeue; queue = [60, 78].
Similar Questions
A queue is an abstract data type that maintains the order in which elements were added to it, allowing the oldest elements to be removed from the front and new elements to be added to the rear. This is called a First-In-First-Out (FIFO) data structure because the first element added to the queue (i.e., the one that has been waiting the longest) is always the first one to be removed.A basic queue has the following operations:Enqueue: add a new element to the end of the queue.Dequeue: remove the element from the front of the queue and return it.In this challenge, you must first implement a queue using two stacks. Then process queries, where each query is one of the following types:1 x: Enqueue element into the end of the queue.2: Dequeue the element at the front of the queue.3: Print the element at the front of the queue.Input FormatThe first line contains a single integer, , denoting the number of queries.Each line of the subsequent lines contains a single query in the form described in the problem statement above. All three queries start with an integer denoting the query , but only query is followed by an additional space-separated value, , denoting the value to be enqueued.ConstraintsIt is guaranteed that a valid answer always exists for each query of type .Output FormatFor each query of type , print the value of the element at the front of the queue on a new line.Sample InputSTDIN Function----- --------10 q = 10 (number of queries)1 42 1st query, enqueue 422 dequeue front element1 14 enqueue 423 print the front element1 28 enqueue 283 print the front element1 60 enqueue 601 78 enqueue 782 dequeue front element2 dequeue front elementSample Output1414ExplanationPerform the following sequence of actions:Enqueue ; .Dequeue the value at the head of the queue, ; .Enqueue ; .Print the value at the head of the queue, ; .Enqueue ; .Print the value at the head of the queue, ; .Enqueue ; .Enqueue ; .Dequeue the value at the head of the queue, ; .Dequeue the value at the head of the queue, ; .
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