19. Remove Nth Node From End of List | Leetcode solution

 19. Remove Nth Node From End of List

Given the head of a linked list, remove the nth node from the end of the list and return its head.

 

Example 1:

Input: head = [1,2,3,4,5], n = 2
Output: [1,2,3,5]

Example 2:

Input: head = [1], n = 1
Output: []

Example 3:

Input: head = [1,2], n = 1
Output: [1]

 

Constraints:

• The number of nodes in the list is sz.
• 1 <= sz <= 30
• 0 <= Node.val <= 100
• 1 <= n <= sz

solution :

/**

 * Definition for singly-linked list.

 * struct ListNode {

 *     int val;

 *     ListNode *next;

 *     ListNode() : val(0), next(nullptr) {}

 *     ListNode(int x) : val(x), next(nullptr) {}

 *     ListNode(int x, ListNode *next) : val(x), next(next) {}

 * };

 */

class Solution {

public:

    ListNode* removeNthFromEnd(ListNode* head, int n) {

        

          ListNode *temp = head;

          ListNode *temp2 = head;

        int k = n;

         while(k--)

         {

             temp2 = temp2->next;

         }

        if(temp2 == NULL)

        {

            temp = temp ->next;

            return temp;

        }

        while(temp2->next != NULL)

        {

             temp = temp->next;

              temp2 = temp2 ->next;

        }

        ListNode* temp3 = temp->next;

        temp ->next = temp3 ->next;

        return head;

    }

};