## Description

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

You are given a string `s`

consisting of lowercase English letters. A **duplicate removal** consists of choosing two **adjacent** and **equal** letters and removing them.

We repeatedly make **duplicate removals** on `s`

until we no longer can.

Return *the final string after all such duplicate removals have been made*. It can be proven that the answer is **unique**.

**Example 1:**

Input:s = "abbaca"Output:"ca"Explanation:For example, in "abbaca" we could remove "bb" since the letters are adjacent and equal, and this is the only possible move. The result of this move is that the string is "aaca", of which only "aa" is possible, so the final string is "ca".

**Example 2:**

Input:s = "azxxzy"Output:"ay"

**Constraints:**

`1 <= s.length <= 10`

^{5}`s`

consists of lowercase English letters.

## Explanation

We can use a stack to solve this problem. We only push the non duplicated adjacent character into the stack.

## Python Solution

```
class Solution:
def removeDuplicates(self, s: str) -> str:
stack = []
for c in s:
if len(stack) > 0 and c == stack[-1]:
stack.pop()
else:
stack.append(c)
return "".join(stack)
```

- Time Complexity: O(N).
- Space Complexity: O(N).

where Q is the length of queries and N is the length of colors.