# 1781. Sum of Beauty of All Substrings

<https://leetcode.com/problems/sum-of-beauty-of-all-substrings>

## Description

The **beauty** of a string is the difference in frequencies between the most frequent and least frequent characters.

* For example, the beauty of `"abaacc"` is `3 - 1 = 2`.

Given a string `s`, return *the sum of **beauty** of all of its substrings.*

**Example 1:**

```
**Input:** s = "aabcb"
**Output:** 5
**Explanation:** The substrings with non-zero beauty are ["aab","aabc","aabcb","abcb","bcb"], each with beauty equal to 1.
```

**Example 2:**

```
**Input:** s = "aabcbaa"
**Output:** 17
```

**Constraints:**

* `1 <= s.length <=500`
* `s` consists of only lowercase English letters.

## ac

```java
```