# https://leetcode.com/problems/remove-all-occurrences-of-a-substring

class Solution:
    def removeOccurrences(self, s: str, part: str) -> str:
        result = []
        def is_part():
            return "".join(result[-len(part):]) == part
        for ch in s:
            result.append(ch)
            if len(result) >= len(part):
                if is_part():
                    for _ in range(len(part)):
                        result.pop()
        return "".join(result)