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# 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

```java
```