Problem
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
.
Solution
/**
* @param {string} s
* @return {string}
*/
var removeStars = function(s) {
var stack = [];
for (var i = 0; i < s.length; i++) {
if (s[i] === '*') {
stack.pop();
} else {
stack.push(s[i]);
}
}
return stack.join('');
};
Explain:
nope.
Complexity:
- Time complexity : O(n).
- Space complexity : O(n).