README_EN.md

2390. Removing Stars From a String

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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:

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

Solutions

Python3

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

Java

class Solution {
    public String removeStars(String s) {
        StringBuilder sb = new StringBuilder();
        for (char c : s.toCharArray()) {
            if (c == '*') {
                sb.deleteCharAt(sb.length() - 1);
            } else {
                sb.append(c);
            }
        }
        return sb.toString();
    }
}

C++

class Solution {
public:
    string removeStars(string s) {
        string ans;
        for (char c : s) {
            if (c == '*') ans.pop_back();
            else ans.push_back(c);
        }
        return ans;
    }
};

Go

func removeStars(s string) string {
	ans := []rune{}
	for _, c := range s {
		if c == '*' {
			ans = ans[:len(ans)-1]
		} else {
			ans = append(ans, c)
		}
	}
	return string(ans)
}

TypeScript

function removeStars(s: string): string {
    const stack = [];
    for (const c of s) {
        if (c === '*') {
            stack.pop();
        } else {
            stack.push(c);
        }
    }
    return stack.join('');
}

Rust

impl Solution {
    pub fn remove_stars(s: String) -> String {
        let mut res = String::new();
        for &c in s.as_bytes().iter() {
            if c == b'*' {
                res.pop();
            } else {
                res.push(char::from(c));
            }
        }
        res
    }
}

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