2000\. Reverse Prefix of Word

Easy

Given a **0-indexed** string `word` and a character `ch`, **reverse** the segment of `word` that starts at index `0` and ends at the index of the **first occurrence** of `ch` (**inclusive**). If the character `ch` does not exist in `word`, do nothing.

*   For example, if `word = "abcdefd"` and `ch = "d"`, then you should **reverse** the segment that starts at `0` and ends at `3` (**inclusive**). The resulting string will be `"dcbaefd"`.

Return _the resulting string_.

**Example 1:**

**Input:** word = "abcdefd", ch = "d"

**Output:** "dcbaefd"

**Explanation:** The first occurrence of "d" is at index 3.

Reverse the part of word from 0 to 3 (inclusive), the resulting string is "dcbaefd". 

**Example 2:**

**Input:** word = "xyxzxe", ch = "z"

**Output:** "zxyxxe"

**Explanation:** The first and only occurrence of "z" is at index 3.

Reverse the part of word from 0 to 3 (inclusive), the resulting string is "zxyxxe". 

**Example 3:**

**Input:** word = "abcd", ch = "z"

**Output:** "abcd"

**Explanation:** "z" does not exist in word.

You should not do any reverse operation, the resulting string is "abcd". 

**Constraints:**

*   `1 <= word.length <= 250`
*   `word` consists of lowercase English letters.
*   `ch` is a lowercase English letter.