1047.removeDuplicates.py

# 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 <= 10⁵
#  s consists of lowercase English letters.
#
#
#  Related Topics String Stack 👍 6334 👎 237


# leetcode submit region begin(Prohibit modification and deletion)
class Solution:
    def removeDuplicates(self, s: str) -> str:
        result = []
        for c in s:
            # e in stack and c are equal
            if result and c == result[-1]:
                # pop the buttom
                result.pop()

            else:  # no duplicates, append
                result.append(c)

        return ''.join(result)


# leetcode submit region end(Prohibit modification and deletion)
if __name__ == '__main__':
    solution = Solution()
    s= "azxxzy"
    print(solution.removeDuplicates(s))  # ay