163. Missing Ranges

Given a sorted integer array nums , where the range of elements are in the inclusive range [ lower , upper ] , return its missing ranges.

Example:

Input:

 

nums


 = 
[0, 1, 3, 50, 75]

, 

lower


 = 0 and 

upper


 = 99,
Output:

 
["2", "4->49", "51->74", "76->99"]