LeetCode 75 - 2390. Removing Stars From a String

Description

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:

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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:

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

Constraints:

1 <= s.length <= 105
s consists of lowercase English letters and stars *.
The operation above can be performed on s.

Solutions

Iterates through each character from left to right. If it is an English letter, it is added to the string. If’ * ’ , delete the last letter in the string.

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class Solution {
public:
    string removeStars(string s) {
        std::string word;
        for (const auto& c : s) {
            if (c == '*' && !word.empty()) {
                word.pop_back();
            } else {
                word.push_back(c);
            }
        }

        return word;
    }
};