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remove-nth-node-from-end.cpp (1087B)

      1 #include <iostream>
      2 using namespace std;
      3 
      4 
      5 //Time: 3ms Beats: 83.17%
      6 //Memory: 10.7MB Beats: 39.89%
      7 
      8 struct ListNode {
      9     int val;
     10     ListNode *next;
     11 };
     12 
     13 
     14 
     15 
     16 ListNode* removeNthFromEnd(ListNode* head, int n) {    
     17     ListNode* itr1 = head;
     18     ListNode* itr2 = head;
     19     int length = 0;
     20     while(itr1 != NULL){
     21         itr1 = itr1->next;
     22         length += 1;
     23     }
     24     n = length - n;
     25     if(n == 0){
     26         return head->next;
     27     }
     28     int count = 0;
     29     while (count < n - 1){
     30         itr2 = itr2->next;
     31         count += 1;
     32     }
     33     ListNode* itr3 = itr2->next;
     34     itr2->next = itr3->next;
     35     return head;
     36 }
     37 
     38 
     39 int main(){
     40 
     41     ListNode* ln1 = new ListNode;
     42     ListNode* ln2 = new ListNode;
     43     ListNode* ln3 = new ListNode;
     44     ListNode* ln4 = new ListNode;
     45     ln1->val = 10;
     46     ln2->val = 4;
     47     ln3->val = 5;
     48     ln4->val = 9;
     49     ln1->next = ln2;
     50     ln2->next = ln3;
     51     ln3->next = ln4;
     52 
     53 
     54     ListNode* itr = removeNthFromEnd(ln1, 2);    
     55     for(int i = 0 ; i < 3; ++i){
     56         cout << itr->val << " ";
     57         itr = itr->next;
     58     }
     59     cout << endl;
     60     return 0;
     61 }