Given a string word, compress it using the following algorithm:
comp. While word is not empty, use the following operation:
<ul>
<li>Remove a maximum length prefix of <code>word</code> made of a <em>single character</em> <code>c</code> repeating <strong>at most</strong> 9 times.</li>
<li>Append the length of the prefix followed by <code>c</code> to <code>comp</code>.</li>
</ul>
</li>
Return the string comp.
Example 1:
Input: word = "abcde"
Output: "1a1b1c1d1e"
Explanation:
Initially, comp = "". Apply the operation 5 times, choosing "a", "b", "c", "d", and "e" as the prefix in each operation.
For each prefix, append "1" followed by the character to comp.
Example 2:
Input: word = "aaaaaaaaaaaaaabb"
Output: "9a5a2b"
Explanation:
Initially, comp = "". Apply the operation 3 times, choosing "aaaaaaaaa", "aaaaa", and "bb" as the prefix in each operation.
"aaaaaaaaa", append "9" followed by "a" to comp."aaaaa", append "5" followed by "a" to comp."bb", append "2" followed by "b" to comp.
Constraints:
1 <= word.length <= 2 * 105word consists only of lowercase English letters.