class Solution {
      public static List<List<Integer>> generate(int numRows) {
        List<List<Integer>> all = new ArrayList();
        
      List<Integer> first = new ArrayList<>();
      first.add(1);
      all.add(first);
      
      if(numRows >=2) {
    	  List<Integer> second = new ArrayList<>();
          second.add(1);
          second.add(1);
          all.add(second);  
      }
      for(int i = 2;i < numRows; i++) {
    	  List<Integer> row = new ArrayList<>();
    	  row.add(1);
    	  int start =0;
    	  for(int j = 1; start<all.get(i-1).size()-1; j++) {
    		  int a = all.get(i-1).get(start)+all.get(i-1).get(start+1);
    		  start++;
    		  row.add(a);
    	  }
    	  
    	 row.add(1);
    	 all.add(row); 
      }
        
        return all;
    }
}

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode() {}
 *     ListNode(int val) { this.val = val; }
 *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 * }
 */
class Solution {
    public ListNode removeNthFromEnd(ListNode head, int n) {
        int len = 0;
        ListNode current = head;
        while(current != null){
            len++;
            current = current.next;
        }
       int required = len - n;
        if(required == 0) return head.next;
        ListNode c = head;
        for(int i =0; i < len; i++){
            if(i == required-1) {
                c.next = c.next.next;
               
            }
             else c = c.next;
        }
        return head;
    }
}