237. Delete Node in a Linked List.cpp

/*
Link: https://leetcode.com/problems/delete-node-in-a-linked-list/

Write a function to delete a node (except the tail) in a singly linked list, given only access to that node.

Given linked list -- head = [4,5,1,9], which looks like following:



 

Example 1:

Input: head = [4,5,1,9], node = 5
Output: [4,1,9]
Explanation: You are given the second node with value 5, the linked list should become 4 -> 1 -> 9 after calling your function.
Example 2:

Input: head = [4,5,1,9], node = 1
Output: [4,5,9]
Explanation: You are given the third node with value 1, the linked list should become 4 -> 5 -> 9 after calling your function.
 

Note:

The linked list will have at least two elements.
All of the nodes' values will be unique.
The given node will not be the tail and it will always be a valid node of the linked list.
Do not return anything from your function.

*/

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    void deleteNode(ListNode* node) {

        node -> val = node -> next -> val;      // copying the value of next node into current node
        node -> next = node -> next -> next;    // delete the node next to the current node

        // second approach
        // *node = *node -> next;               // replacing the address of the node pointer to 
                                                // its next node's pointer address
    }
};

/*
TC = O(1)
SC = O(1)
*/