1876. Substrings of Size Three with Distinct Characters

https://leetcode.com/problems/substrings-of-size-three-with-distinct-characters

Description

A string is good if there are no repeated characters.

Given a string s​​​​​, return the number of good substrings of length three in s​​​​​​.

Note that if there are multiple occurrences of the same substring, every occurrence should be counted.

A substring is a contiguous sequence of characters in a string.

Example 1:

**Input:** s = "xyzzaz"
**Output:** 1
**Explanation:** There are 4 substrings of size 3: "xyz", "yzz", "zza", and "zaz". 
The only good substring of length 3 is "xyz".

Example 2:

**Input:** s = "aababcabc"
**Output:** 4
**Explanation:** There are 7 substrings of size 3: "aab", "aba", "bab", "abc", "bca", "cab", and "abc".
The good substrings are "abc", "bca", "cab", and "abc".

Constraints:

• 1 <= s.length <= 100

• s​​​​​​ consists of lowercase English letters.

ac