1209. Remove All Adjacent Duplicates in String II

https://leetcode.com/problems/remove-all-adjacent-duplicates-in-string-ii

Description

You are given a string s and an integer k, a k duplicate removal consists of choosing k adjacent and equal letters from s and removing them, causing the left and the right side of the deleted substring to concatenate together.

We repeatedly make k duplicate removals on s until we no longer can.

Return the final string after all such duplicate removals have been made. It is guaranteed that the answer is unique.

Example 1:

**Input:** s = "abcd", k = 2
**Output:** "abcd"
**Explanation:** There's nothing to delete.

Example 2:

**Input:** s = "deeedbbcccbdaa", k = 3
**Output:** "aa"
**Explanation:**First delete "eee" and "ccc", get "ddbbbdaa"
Then delete "bbb", get "dddaa"
Finally delete "ddd", get "aa"

Example 3:

**Input:** s = "pbbcggttciiippooaais", k = 2
**Output:** "ps"

Constraints:

• 1 <= s.length <= 105

• 2 <= k <= 104

• s only contains lower case English letters.

ac