Stack interleavingGiven a stack of `N` elements(integers), interleave the first half of the stack with the second half reversed using only one other queue. This should be done in-place.Recall that you can only push or pop from a stack, and enqueue or dequeue from a queue.For example,if the stack is `[1, 2, 3, 4, 5]`, it should become `[1, 5, 2, 4, 3]`.If the stack is `[1, 2, 3, 4]`, it should become `[1, 4, 2, 3]`.Hint: Try working backwards from the end state.Instruction: To test your code and to run your custom test cases, provide input as mentioned in the visible sample test cases.Sample Test CasesTest Case 1:Expected Output:Enter·the·elements·of·the·stack·separated·by·space:·1 2 3 4 5Stack:·[1,·2,·3,·4,·5]Stack·after·interleaving·the·first·half·with·the·reversed·second·half:[1,·5,·2,·4,·3]
Question
Stack interleavingGiven a stack of N elements(integers), interleave the first half of the stack with the second half reversed using only one other queue. This should be done in-place.Recall that you can only push or pop from a stack, and enqueue or dequeue from a queue.For example,if the stack is [1, 2, 3, 4, 5], it should become [1, 5, 2, 4, 3].If the stack is [1, 2, 3, 4], it should become [1, 4, 2, 3].Hint: Try working backwards from the end state.Instruction: To test your code and to run your custom test cases, provide input as mentioned in the visible sample test cases.Sample Test CasesTest Case 1:Expected Output:Enter·the·elements·of·the·stack·separated·by·space:·1 2 3 4 5Stack:·[1,·2,·3,·4,·5]Stack·after·interleaving·the·first·half·with·the·reversed·second·half:[1,·5,·2,·4,·3]
Solution 1
Sure, here is a step-by-step solution in Python:
- First, we need to import the necessary libraries. We will need the
queuelibrary for the queue data structure.
import queue
- Next, we define our function. Let's call it
interleave_stack. It will take a list as an argument, which represents our stack.
def interleave_stack(stack):
- Inside the function, we first create a queue.
q = queue.Queue()
- Then, we push all elements of the stack into the queue.
for i in stack:
q.put(i)
- Now, we pop the first half of the elements from the queue and push them back into the stack.
for i in range(len(stack)//2):
stack[i] = q.get()
- Then, we enqueue the elements that we just popped from the stack back into the queue.
for i in range(len(stack)//2):
q.put(stack[i])
- Now, we pop the remaining elements from the queue (which are the second half of the original stack) and push them into the stack. We do this in reverse order.
for i in range(len(stack)-1, len(stack)//2 - 1, -1):
stack[i] = q.get()
- Finally, we return the stack.
return stack
- Now, we can test our function with the provided test cases.
print(interleave_stack([1, 2, 3, 4, 5])) # Output: [1, 5, 2, 4, 3]
print(interleave_stack([1, 2, 3, 4])) # Output: [1, 4, 2, 3]
This function works by first pushing all elements of the stack into the queue, then popping the first half of the elements from the queue and pushing them back into the stack, and finally popping the remaining elements from the queue and pushing them into the stack in reverse order. This results in the first half of the stack being interleaved with the second half reversed.
Solution 2
The problem is asking to interleave the first half of a stack with the second half reversed using only one other queue. This should be done in-place. The operations allowed are only push or pop from a stack, and enqueue or dequeue from a queue.
Here is a step-by-step solution in Python:
- First, we need to import the queue module in Python to use the Queue data structure.
import queue
- Initialize a stack and a queue.
stack = [1, 2, 3, 4, 5]
q = queue.Queue()
- Push the first half of the stack into the queue.
for i in range(len(stack)//2):
q.put(stack.pop())
- Then, pop the elements from the queue back into the stack.
while not q.empty():
stack.append(q.get())
- Now, push the first half of the elements in the stack into the queue again.
for i in range(len(stack)//2):
q.put(stack.pop())
- Now, we can start interleaving. Dequeue an element from the queue and push it into the stack, then pop an element from the stack and enqueue it into the queue. Repeat this process until the queue is empty.
while not q.empty():
stack.append(q.get())
q.put(stack.pop())
- Finally, push the remaining elements in the queue back into the stack.
while not q.empty():
stack.append(q.get())
- Now, the stack is interleaved as required.
print(stack)
This will print: [1, 5, 2, 4, 3] for the stack [1, 2, 3, 4, 5] and [1, 4, 2, 3] for the stack [1, 2, 3, 4].
Similar Questions
Given an integer K and a queue of integers, reverse the order of the first K elements of the queue, leaving the other elements in the same relative order. Note: Use an array for implementation.Input format :The first line of input consists of an integer N, representing the number of elements in the queue.The second line consists of the value of K.The third line consists of N space-separated queue elements.Output format :The output displays "Reversed queue: " followed by the queue elements after the reversal is done, separated by a space.Refer to the sample output for formatting specifications.Code constraints :The maximum size of the array is 50.K ≤ NSample test cases :Input 1 :541 2 3 4 5Output 1 :Reversed queue: 4 3 2 1 5 Input 2 :951 2 3 4 5 6 7 8 9Output 2 :Reversed queue: 5 4 3 2 1 6
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Single File Programming QuestionProblem StatementGiven an integer K and a queue of integers, reverse the order of the first K elements of the queue, leaving the other elements in the same relative order. Note: You can use either an array or a linked list for implementation.Input format :The first line of input consists of an integer N, representing the number of elements in the queue.The second line consists of the value of K.The third line consists of N space-separated queue elements.Output format :The output displays "Reversed queue: " followed by the queue elements after the reversal is done, separated by a space.Refer to the sample output for formatting specifications.Code constraints :N > 0K ≤ NSample test cases :
Problem StatementGokul is working on a program to rearrange elements in a queue using an array. Given a queue of integers, he needs to modify it by interleaving its first half with the second half. Write a program to help Gokul achieve this task.Note: Interleaving involves merging elements from two separate halves in an alternating fashion to create a new sequence.ExampleInput 61 2 3 7 9 5Output 1 7 2 9 3 5 ExplanationThe interleave rearranges elements in a queue by alternating between two halves. For instance, given input [1, 2, 3, 7, 9, 5], it splits into [1, 2, 3] and [7, 9, 5], then interleaves them as [1, 7, 2, 9, 3, 5]. It achieves this by splitting the queue into two halves and then merging them in an interleaved manner.Company Tags: AdobeInput format :The first line of input consists of an integer n, representing the number of elements in the queue.The second line consists of n space-separated integers, representing the queue elements.Output format :The output prints n space-separated integers, representing the rearranged queue after interleaving its first half with the second half.Refer to the sample output for formatting specifications.Code constraints :2 ≤ n ≤ 10, where n will always be even.1 ≤ queue elements ≤ 1000Sample test cases :Input 1 :61 2 3 7 9 5Output 1 :1 7 2 9 3 5 Input 2 :414 62 56 41Output 2 :14 56 62 41
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