Google Online Assessment (OA) 2021 | Split Strings

Given a string s with length n, how many ways can you split it into two substrings s_1 and s_2 such that the number of unique characters in s_1 and s_2 are the same?


  • s: A string with length n.


  • The number of ways you can split it into two substrings that satisfy the condition.


Example 1:

Input: s = "aaa"

Output: 2

Explanation: It can be split in two ways: "a", "aa" and "aa", "a".

Example 2:

Input: s = "bac"

Output: 0

Explanation: There is no way to split this string into two substrings with equal unique elements.


  • 0 <= n <= 10^5
  • Characters in this string may consist of any alphanumeric character. The characters are case sensitive. That is, same letters with different cases count as different characters.

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