We are given n ranges `(L1,R1) , (L2,R2) , ... .. (Ln,Rn)`

All ranges are integer values between `(0 to 10^6)`

. We have to find out the `total number of unique integers`

across all the ranges?

Ex. For n = 3, (1,4) , (2,3) , (4,5) the answer is 5.

My solution is to sort the ranges according to their L value and then iterate one by one using two pointers. My Time Complexity`O(n*Log(n))`

.

Is there `any better solution`

than my solution(may be using Hash Maps)?