Grokking Data Structures & Algorithms for Coding Interviews
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Problem 1: Reverse Linked List (easy)
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Problem Statement:

Given the head of a singly linked list, your task is to reverse the list and return its head. The singly linked list has nodes, and each node contains an integer and a pointer to the next node. The last node in the list points to null, indicating the end of the list.

Examples

Example 1:

  • Input: [3, 5, 2]
  • Expected Output: [2, 5, 3]
  • Justification: Reversing the list [3, 5, 2] gives us [2, 5, 3].

Example 2:

  • Input: [7]
  • Expected Output: [7]
  • Justification: Since there is only one element in the list, the reversed list remains the same.

Example 3:

  • Input: [-1, 0, 1]
  • Expected Output: [1, 0, -1]
  • Justification: The list is reversed, so the elements are in the order [1, 0, -1].

Constraints:

  • The number of nodes in the list is the range [0, 5000].
  • -5000 <= Node.val <= 5000

Try it yourself

Try solving this question here:

Python3
Python3
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