2068\. Check Whether Two Strings are Almost Equivalent

Easy

Two strings `word1` and `word2` are considered **almost equivalent** if the differences between the frequencies of each letter from `'a'` to `'z'` between `word1` and `word2` is **at most** `3`.

Given two strings `word1` and `word2`, each of length `n`, return `true` _if_ `word1` _and_ `word2` _are **almost equivalent**, or_ `false` _otherwise_.

The **frequency** of a letter `x` is the number of times it occurs in the string.

**Example 1:**

**Input:** word1 = "aaaa", word2 = "bccb"

**Output:** false

**Explanation:** There are 4 'a's in "aaaa" but 0 'a's in "bccb". 

The difference is 4, which is more than the allowed 3. 

**Example 2:**

**Input:** word1 = "abcdeef", word2 = "abaaacc"

**Output:** true

**Explanation:** The differences between the frequencies of each letter in word1 and word2 are at most 3:
 
- 'a' appears 1 time in word1 and 4 times in word2. The difference is 3.

- 'b' appears 1 time in word1 and 1 time in word2. The difference is 0.

- 'c' appears 1 time in word1 and 2 times in word2. The difference is 1.

- 'd' appears 1 time in word1 and 0 times in word2. The difference is 1.

- 'e' appears 2 times in word1 and 0 times in word2. The difference is 2.

- 'f' appears 1 time in word1 and 0 times in word2. The difference is 1. 

**Example 3:**

**Input:** word1 = "cccddabba", word2 = "babababab"

**Output:** true

**Explanation:** The differences between the frequencies of each letter in word1 and word2 are at most 3:

- 'a' appears 2 times in word1 and 4 times in word2. The difference is 2.

- 'b' appears 2 times in word1 and 5 times in word2. The difference is 3.

- 'c' appears 3 times in word1 and 0 times in word2. The difference is 3.

- 'd' appears 2 times in word1 and 0 times in word2. The difference is 2. 

**Constraints:**

*   `n == word1.length == word2.length`
*   `1 <= n <= 100`
*   `word1` and `word2` consist only of lowercase English letters.
