2390. Removing Stars From a String

Medium
​
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.

解題

使用 Stack 來進行消除
func removeStars(s string) string {
stack := make([]byte, 0)
​
for i := 0; i < len(s); i++ {
if len(stack) == 0 {
stack = append(stack, s[i])
} else {
if s[i] == '*' {
stack = stack[:len(stack)-1]
} else {
stack = append(stack, s[i])
}
}
}
​
return string(stack)
}