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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:

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

  • class Solution {
        public String removeStars(String s) {
            StringBuilder ans = new StringBuilder();
            for (int i = 0; i < s.length(); ++i) {
                if (s.charAt(i) == '*') {
                    ans.deleteCharAt(ans.length() - 1);
                } else {
                    ans.append(s.charAt(i));
                }
            }
            return ans.toString();
        }
    }
    
  • 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;
        }
    };
    
  • class Solution:
        def removeStars(self, s: str) -> str:
            ans = []
            for c in s:
                if c == '*':
                    ans.pop()
                else:
                    ans.append(c)
            return ''.join(ans)
    
    
  • 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)
    }
    
  • function removeStars(s: string): string {
        const ans: string[] = [];
        for (const c of s) {
            if (c === '*') {
                ans.pop();
            } else {
                ans.push(c);
            }
        }
        return ans.join('');
    }
    
    
  • class Solution {
        /**
         * @param String $s
         * @return String
         */
        function removeStars($s) {
            $rs = [];
            for ($i = 0; $i < strlen($s); $i++) {
                if ($s[$i] == '*') {
                    array_pop($rs);
                } else {
                    array_push($rs, $s[$i]);
                }
            }
            return join($rs);
        }
    }
    
    
  • impl Solution {
        pub fn remove_stars(s: String) -> String {
            let mut ans = String::new();
            for &c in s.as_bytes().iter() {
                if c == b'*' {
                    ans.pop();
                } else {
                    ans.push(char::from(c));
                }
            }
            ans
        }
    }
    
    

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