medium
2 min read
List reversal
List reversal is a process of arranging the elements of a linked list in the opposite order of their original order. This can be achieved by traversing the...
Quick Actions
Insights
Difficultymedium
Reading Time2 min
List reversal is a process of arranging the elements of a linked list in the opposite order of their original order. This can be achieved by traversing the...
List reversal is a process of arranging the elements of a linked list in the opposite order of their original order. This can be achieved by traversing the linked list and reversing the order of the pointers to the nodes.
Example:
Original linked list:
A --> B --> C --> D --> E
Reversed linked list:
E --> D --> C --> B --> A
Steps to reverse a linked list:
Start at the head of the linked list. The head pointer points to the first node in the linked list.
Move one node at a time from the head to the end of the linked list. This can be done by dereferencing the head pointer and updating the head pointer to point to the next node.
Reverse the order of the pointers to the nodes. This can be done by swapping the pointers to the next node and the pointer to the previous node.
Continue to step 2 until the end of the linked list is reached.
Set the pointer to the head of the reversed linked list. This will mark the end of the reversed list.
Return from the head of the reversed linked list.
Time complexity: O(n), where n is the length of the linked list. This is because the algorithm iterates over the entire linked list once to reverse it.
Space complexity: O(1), as the algorithm only requires a temporary variable to store the reversed linked list.
Applications of list reversal:
Sorting linked lists: By reversing the order of the elements, you can sort the linked list in reverse order.
Printing linked lists: You can reverse the order of the elements in a linked list and print them in reverse order.
Removing cycles from linked lists: Reversing the order of the elements can help you remove cycles from a linked list