Description
Given a string s, repeatedly remove adjacent duplicate letters. Continue removing duplicates until no adjacent pair of equal characters remains. Return the result as a string.
Examples
Input:
s = "abbaca"Output:
"ca"Explanation:
Using a stack: 'abbaca' → remove 'bb' → 'aaca' → remove 'aa' → 'ca'. The final result is 'ca'.
Input:
s = "abccba"Output:
""Explanation:
Remove cc to get "abba", then remove bb to get "aa", finally remove aa to get empty string.
Input:
s = "aabbccdd"Output:
""Explanation:
Remove aa to get "bbccdd", then remove bb to get "ccdd", then remove cc to get "dd", finally remove dd to get empty string.
Constraints
- •
1 ≤ s.length ≤ 10⁵