1525. Number of Good Ways to Split a String

You are given a string s. A split is called good if you can split s into two non-empty strings sleft and sright where their concatenation is equal to s (i.e., sleft + sright = s) and the number of distinct letters in sleft and sright is the same. Return the number of good splits you can make in s. Example 1: Input: s = "aacaba" Output: 2 Explanation: There are 5 ways to split "aacaba" and 2