Update README.md

Author: kamyu104

README.md

@@ -368,7 +368,7 @@ Problem         |  Solution       |  Time           | Space           | Difficul
 [Insertion Sort List]|[insertion-sort-list.py] | _O(n^2)_ | _O(1)_    | Medium         |
 [Largest Number] | [largest-number.py] | _O(n^2)_   | _O(n)_          | Medium         |
 [Maximum Gap]   | [maximum-gap.py]| _O(n)_          | _O(n)_          | Hard           | Tricky 
-[Merge Intervals]| [merge-intervals.py] | _O(n^2)_  | _O(1)_          | Hard           |
+[Merge Intervals]| [merge-intervals.py] | _O(nlogn)_  | _O(1)_        | Hard           |
 [Merge Sorted Array]| [merge-sorted-array.py] | _O(n)_ | _O(1)_       | Easy           |
 [Merge Two Sorted Lists]| [merge-two-sorted-lists.py] | _O(n)_ | _O(1)_ | Easy         |
 [Sort Colors]   | [sort-colors.py] | _O(n)_         | _O(1)_          | Medium         |