Update Extra

Author: Ashishgup1

Extra

@@ -89,6 +89,6 @@
 //Problem 1 (Getting a sequence of + and - by using a sequence of - operationss): http://p.ip.fi/6t7b
 //Problem 2 (Number of ways to place elements such that adjacent are different and given L and R) : https://www.codechef.com/BLUP2019/problems/AHAPH/
 //Problem 3 (Merge Sort Tree): https://codeforces.com/contest/369/problem/E
-
+//Problem 4 ([N/x] ranges): https://www.hackerrank.com/contests/hourrank-7/challenges/tile-painting-revisited/problem
 Resources:
 https://www.careerbless.com/aptitude/qa/permutations_combinations_imp7.php