[2272. Substring With Largest Variance](https://leetcode.com/problems/substring-with-largest-variance/)

### 題目描述

The **variance** of a string is defined as the largest difference between the number of occurrences of **any** `2` characters present in the string. Note the two characters may or may not be the same.

Given a string `s` consisting of lowercase English letters only, return *the **largest variance** possible among all **substrings** of* `s`.

A **substring** is a contiguous sequence of characters within a string.

### 範例

**Example 1:**

Input: s = "aababbb"
Output: 3
Explanation:
All possible variances along with their respective substrings are listed below:
- Variance 0 for substrings "a", "aa", "ab", "abab", "aababb", "ba", "b", "bb", and "bbb".
- Variance 1 for substrings "aab", "aba", "abb", "aabab", "ababb", "aababbb", and "bab".
- Variance 2 for substrings "aaba", "ababbb", "abbb", and "babb".
- Variance 3 for substring "babbb".
Since the largest possible variance is 3, we return it.

**Example 2:**

Input: s = "abcde"
Output: 0
Explanation:
No letter occurs more than once in s, so the variance of every substring is 0.

**Constraints**:

* 1 <= `s.length` <= 10^4^
* `s` consists of lowercase English letters.

### 解答

### Reference

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