Kth from the end
- argument: a number,
k, as a parameter, which denotes how far the node is from the tail of the linked list. - Return the node’s value that is
kplaces from the tail of the linked list. - You have access to the Node class and all the properties on the Linked List class as well as the methods created in previous challenges.
- This will use code from Linked List Insertions
Figjam Link for Code Challenge 7-- to navigate the image embedded above
For all methods, the time big O for these is the length of the linked list that you must traverse to find the target node, or the last node of the list, so : O(n), where n is the length of the linked list. The space is still O(1), since all the nodes still exist in memory, but that memory is dynamic, so it need not take up a larger chunk of memory at once.
When testing, I hit some bugs on my condition for the inner loop. Originally, I had the code move the k_node move once k hit 0, but that means that it ran at 0, not the loop after. So to counteract, I changed it to when the value of k is at -1, so it will run the loop after 0, which is when I actually wanted it to start moving. Based on my looping logic, both my length variable and my k variable had to + 1 before the loop started, so that its first run of the loop would have the correct starting value. That is, the length variable had to start at 1 instead of 0, and the k variable had to start at k+1 instead of just k.
That being said, when it came to raising my custom error, for the comparison, I needed k to be greater than length -2, to account for the additions I made on both values before the loop.
Terminal command: python3 -m linked_list_kth.linked_list_kth
Terminal command : python3 -m pytest linked_list_kth/