Count Residue Prefixes
You are given a string s consisting only of lowercase English letters.
A prefix of s is called a residue if the number of distinct characters in the prefix is equal to len(prefix) % 3.
Return the count of residue prefixes in s.
A prefix of a string is a non-empty substring that starts from the beginning of the string and extends to any point within it.
Example 1
Input
s = "abc"Output
2Prefixes
"a" and "ab" satisfy the condition, while "abc" does not, so the answer is 2.Example 2
Input
s = "dd"Output
1Prefix
"d" satisfies the condition, while "dd" does not, so the answer is 1.Constraints
- 1 <= s.length <= 100
- s contains only lowercase English letters.