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Hi everyone, let's solve this question.

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You are given the head of a singly linked list.

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Write a function that will take the given head as input.

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Reverse the linked list and return the new head of the reversed linked list.

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All right, so this is the question.

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Now you are given a singly linked list.

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And the input.

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We are right.

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We have to write a function.

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The input to the function is the head of this singly linked list.

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And we have to reverse it and return the new head.

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So that's the question.

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Now remember in the interview when you are doing this, you can always ask clarifying questions so that

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you have a thorough understanding of the question.

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Now a possible question could be what if the input is only a single node?

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Now let's say the interviewer replies return the node itself at that point.

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All right.

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Now another possible question could be what should be returned if the input is null?

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Now let's say the interviewer replies.

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In this case, just return null.

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All right.

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Now the question is fairly straightforward, so probably no more clarifying questions are required.

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Now let's go ahead and write some test cases to identify if there are any particular edge cases that

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we need to take care, and to ensure that you and the interviewer are on the same page.

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Now remember, test cases are just various inputs and outputs that are expected in those cases.

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And when you write test cases, especially if the question is tricky, you can ask the interviewer whether

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it's okay that you come up together with some test cases.

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Now let's go ahead and write some test cases.

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Let's say the input is this singly linked list one.

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The node with value one goes to two.

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That goes to three that goes to four.

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And then that points to null.

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Now if this is the input the output should be 4321.

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And that points to null.

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Right now if the input is just a single node, then the output as we clarified, has to be just that

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particular single node.

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And if the input is null, then the output has to be just null.

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So that's pretty straightforward.

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Now let's go ahead and see how we can solve this question.

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And what logic or what method we can use to solve this question.