make-the-string-great_1544.py

# Given a string s of lower and upper case English letters.

# A good string is a string which doesn't have two adjacent characters s[i] and s[i + 1] where:

# 0 <= i <= s.length - 2
# s[i] is a lower-case letter and s[i + 1] is the same letter but in upper-case or vice-versa.
# To make the string good, you can choose two adjacent characters that make
# the string bad and remove them. You can keep doing this until the string becomes good.

# Return the string after making it good. The answer is guaranteed to be unique under the given constraints.

# Notice that an empty string is also good.


# Example 1:

# Input: s = "leEeetcode"
# Output: "leetcode"
# Explanation: In the first step, either you choose i = 1 or i = 2,
# both will result "leEeetcode" to be reduced to "leetcode".
# Example 2:

# Input: s = "abBAcC"
# Output: ""
# Explanation: We have many possible scenarios, and all lead to the same answer. For example:
# "abBAcC" --> "aAcC" --> "cC" --> ""
# "abBAcC" --> "abBA" --> "aA" --> ""
# Example 3:

# Input: s = "s"
# Output: "s"

# ---------------------------------------Runtime 40 ms Beats 43.60% Memory 16.55 MB Beats 48.83%---------------------------------------
# Type: Stack


# My solution
class Solution:
    def makeGood(self, s: str) -> str:
        res = list(s)
        i = 0

        while i < len(res) - 1 and res:
            if res[i].lower() == res[i + 1].lower() and res[i] != res[i + 1]:

                res.pop(i)
                res.pop(i)
                if i - 1 >= 0:
                    i -= 1
            else:
                i += 1

        return "".join(res)