Update Interview_Questions.md

Author: Amogh Singhal

Interview_Questions.md

@@ -1,5 +1,8 @@
-## 1. How to find the middle element of a linked list
+## 1. How to find the middle element of a linked list in one pass
 Solution: Start with two pointer `p` and `q`. For every second iteration of `p`, iterate `q`. When `p` reaches the end of the linked list. `q` will be in the middle of the list.
 
-## 2. How to find the loop or cycle in a linked list
+## 2. How to find the loop or cycle in a linked list in one pass
 Solution: Start with two pointer `p` and `q`. For every second iteration of `p`, iterate `q`. If `p` and `q` are pointing to the same node, there is a loop or cycle present.
+
+## 3. How to find the `k th` element from a linked list in one pass
+Solution: Start with two pointer `p` and `q`. When the `p` pointer reahces upto the `k th` element, increment `q`.When `p` reaches the end of the list. `q` is ponting to the element 'k th' from the end.