文章目录
一、题目
2390. Removing Stars From a String
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**code". s becomes "leecod*e".
- The closest character to the 2nd star is 'e' in "leecode". 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.
二、题解
利用栈解决问题
cpp
class Solution {
public:
string removeStars(string s) {
int n = s.length();
stack<char> st;
string res = "";
for(int i = 0;i < n;i++){
char c = s[i];
if(c != '*') st.push(c);
else if(c == '*' && !st.empty()) st.pop();
}
while(st.size()) res += st.top(),st.pop();
reverse(res.begin(),res.end());
return res;
}
};