2390. Removing Stars From a String
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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 <= 105sconsists of lowercase English letters and stars*.- The operation above can be performed on
s.
Hints
Hint 1
What data structure could we use to efficiently perform these removals?
Hint 2
Use a stack to store the characters. Pop one character off the stack at each star. Otherwise, we push the character onto the stack.