Reverse Linked List Problem Statement

Given a singly linked list of integers, return the head of the reversed linked list.

Example:

Initial linked list: 1 - 2 - 3 - 4 - NULL Reversed linked list: 4 - 3 - 2 - 1 - NULL The head of the reversed linked list is 4.

Follow Up:

Can you solve this problem in O(N) time and O(1) space complexity?

Input:

The first line contains an integer 'T' representing the number of test cases. Each test case consists of a single line containing the elements of the singly linked list, separated by a space and terminated with -1 (indicating the end of the list). The value -1 is not part of the list.

Output:

For each test case, print the reversed linked list in a separate line.

Constraints:

1

Question

Reverse Linked List Problem Statement

Given a singly linked list of integers, return the head of the reversed linked list.

Example:

Initial linked list: 1 -> 2 -> 3 -> 4 -> NULL
Reversed linked list: 4 -> 3 -> 2 -> 1 -> NULL
The head of the reversed linked list is 4.

Follow Up:

Can you solve this problem in O(N) time and O(1) space complexity?

Input:

The first line contains an integer 'T' representing the number of test cases.
Each test case consists of a single line containing the elements of the singly linked list, separated by a space and terminated with -1 (indicating the end of the list). The value -1 is not part of the list.

Output:

For each test case, print the reversed linked list in a separate line.

Constraints:

1 <= T <= 5
0 <= L <= 10^5
1 <= data <= 10^9 and data ≠ -1
Time Limit: 1 sec

Note:

You do not need to print anything; implement the function provided.

Accepted Answer

Reverse a singly linked list of integers and return the head of the reversed linked list.

Iterate through the linked list and reverse the pointers to point to the previous node instead of the next node.
Use three pointers to keep track of the current, previous, and next nodes while reversing the linked list.
Update the head of the reversed linked list as the last node encountered during the reversal process.