[leetcode] 2390. Removing Stars From a String _ Algorithm Problem Solve for python

1. Problem

2390. Removing Stars From a String

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.

Constraints:

• 1 <= s.length <= 10^5
• s consists of lowercase English letters and stars *.
• The operation above can be performed on s.

2. Solution

I solved this problem like this.

• Using stack, the problem can be solved easily.

class Solution:
    def removeStars(self, s: str) -> str:
        stack = []
        for x in s:
            if x == '*':
                stack.pop()
            else:
                stack.append(x)
        return ''.join(stack)