2025-08-21 12:03:03 +0000 UTC

Minimum String Length After Removing Substrings
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Code

class Solution:
    def minLength(self, s: str) -> int:
        stack = []
        for char in s:
            if not stack or char not in "ABCD":
                stack.append(char)
                continue
            if (
                (stack[-1] == "A" and char == "B") 
                or (stack[-1] == "C" and char == "D")
            ):
                stack.pop()
            else:
                stack.append(char)
        return len(stack)