Solution 1: Simulation

We can directly traverse the string according to the requirements of the problem, and append characters that are not vowels to the result string.

The time complexity is $O (n)$ , where $n$ is the length of the string. Ignoring the space consumption of the answer, the space complexity is $O (1)$ .

Python3

class Solution:
    def removeVowels(self, s: str) -> str:
        return "".join(c for c in s if c not in "aeiou")

Java

class Solution {
    public String removeVowels(String s) {
        StringBuilder ans = new StringBuilder();
        for (int i = 0; i < s.length(); ++i) {
            char c = s.charAt(i);
            if (!(c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u')) {
                ans.append(c);
            }
        }
        return ans.toString();
    }
}

C++

class Solution {
public:
    string removeVowels(string s) {
        string ans;
        for (char& c : s) {
            if (!(c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u')) {
                ans += c;
            }
        }
        return ans;
    }
};

Go

func removeVowels(s string) string {
    ans := []rune{}
    for _, c := range s {
        if !(c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u') {
            ans = append(ans, c)
        }
    }
    return string(ans)
}

TypeScript

function removeVowels(s: string): string {
    return s.replace(/[aeiou]/g, '');
}

Problem