[알고리즘문제풀기] 문자열 뒤집기

문제

내가 작성한 정답

// String
class Solution {
    public String solution(String my_string, int s, int e) {
        String answer = my_string.substring(0,s);
        for(int i=e; i>=s; i--){
            answer += my_string.charAt(i);
        }
        answer += my_string.substring(e+1,my_string.length());
        return answer;
    }
}

// Stringbuffer
class Solution {
    public String solution(String my_string, int s, int e) {
        StringBuilder answer = new StringBuilder();
        answer.append(my_string.substring(0,s));
        for(int i = e; i>=s; i--){
            answer.append(my_string.charAt(i));
        }
        answer.append(my_string.substring(e+1,my_string.length()));
        return answer.toString();
    }
}

//stream
import java.util.stream.*;

class Solution {
    public String solution(String my_string, int s, int e) {
        String answer = "";

        return IntStream.range(0,my_string.length())
                .mapToObj(i-> (i>=s && i<=e)?my_string.charAt(s+e-i):my_string.charAt(i))
                .map(String::valueOf)
                .collect(Collectors.joining());
	               //.reduce("",String::concat);
    }
}

다른 사람들의 정답

StringBuilder - reverse()

class Solution {
    public String solution(String my_string, int s, int e) {
        StringBuilder answer = new StringBuilder(my_string.substring(s, e + 1));
        answer.reverse();
        return my_string.substring(0, s) + answer + my_string.substring(e + 1);
    }
}

class Solution {
    public String solution(String myString, int s, int e) {
        return myString.substring(0, s) + new StringBuilder(myString.substring(s, e + 1)).reverse().toString() + myString.substring(e + 1);
    }
}

while

class Solution {
    public String solution(String my_string, int s, int e) {

        char[] arr = my_string.toCharArray();
        while (s < e) {
            char temp = arr[s];
            arr[s++] = arr[e];
            arr[e--] = temp;
        }

        return new String(arr);
    }
}