You are given a string s
.
A split is called good if you can split s
into two nonempty strings s_{left}
and s_{right}
where their concatenation is equal to s
(i.e., s_{left} + s_{right} = s
) and the number of distinct letters in s_{left}
and s_{right}
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 of them are good.
("a", "acaba") Left string and right string contains 1 and 3 different letters respectively.
("aa", "caba") Left string and right string contains 1 and 3 different letters respectively.
("aac", "aba") Left string and right string contains 2 and 2 different letters respectively (good split).
("aaca", "ba") Left string and right string contains 2 and 2 different letters respectively (good split).
("aacab", "a") Left string and right string contains 3 and 1 different letters respectively.
Example 2:
Input: s = "abcd"
Output: 1
Explanation: Split the string as follows ("ab", "cd").
Constraints:
1 <= s.length <= 10^{5}
s
consists of only lowercase English letters.

