removing-stars-from-a-string_2390.py

# You are given a string s, which contains stars *.

# In one operation, you can:

# Choose a star in s.
# Remove the closest non-star character to its left, as well as remove the star itself.
# Return the string after all stars have been removed.

# Note:

# The input will be generated such that the operation is always possible.
# It can be shown that the resulting string will always be unique.


# Example 1:

# Input: s = "leet**cod*e"
# Output: "lecoe"
# Explanation: Performing the removals from left to right:
# - The closest character to the 1st star is 't' in "leet**cod*e". s becomes "lee*cod*e".
# - The closest character to the 2nd star is 'e' in "lee*cod*e". s becomes "lecod*e".
# - The closest character to the 3rd star is 'd' in "lecod*e". s becomes "lecoe".
# There are no more stars, so we return "lecoe".
# Example 2:

# Input: s = "erase*****"
# Output: ""
# Explanation: The entire string is removed, so we return an empty string.

# ---------------------------------------Runtime 177 ms Beats 93.6% Memory 18 MB Beats 41.36%---------------------------------------


# Solution O(n)
class Solution:
    def removeStars(self, s: str) -> str:
        stack = []
        for letter in s:
            stack.pop() if letter == "*" else stack.append(letter)

        return "".join(stack)