Is there a simpler solution? - java help on CodeGym

Hi, I passed the task, but am just wondering if there's a simpler solution. I think I wouldn't been able to finish it without method Reverse part, which I found on stack overflow.

public class Solution {
    public static void main(String[] args) throws IOException {

        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        String fileName = bufferedReader.readLine();
        bufferedReader.close();

        BufferedReader bufferedReader1 = new BufferedReader(new FileReader(fileName));
        ArrayList<String> arrayList = new ArrayList<>();
        ArrayList<String> arrayList1 = new ArrayList<>();

        while (bufferedReader1.ready()) {
            String line = bufferedReader1.readLine();
            arrayList.add(line);
        }

        bufferedReader1.close();

        for (String s : arrayList) {
            arrayList1.add(Reverse(s));
        }

        for (String s : arrayList1) {
            System.out.println(s);
        }
    }

    private static String Reverse(String str) {
        StringBuilder result = new StringBuilder();
        StringTokenizer st = new StringTokenizer(str, "");
        while (st.hasMoreTokens()) {
            StringBuilder thisToken = new StringBuilder(st.nextToken());
            result.append(thisToken.reverse()).append(" ");
        }
        return result.toString();
    }
}

public class Solution { public static void main(String[] args) throws IOException { BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in)); String fileName = bufferedReader.readLine(); bufferedReader.close(); BufferedReader bufferedReader1 = new BufferedReader(new FileReader(fileName)); // var arrayList = new ArrayList<String>(); // ArrayList<String> arrayList1 = new ArrayList<>(); while (bufferedReader1.ready()) { // String line = bufferedReader1.readLine(); // arrayList.add(line); System.out.println(new StringBuilder(bufferedReader1.readLine()).reverse()); } bufferedReader1.close(); // for (String s : arrayList) { // arrayList1.add(Reverse(s)); // } // // for (String s : arrayList1) { // System.out.println(s); // } } // private static String Reverse(String str) { // StringBuilder result = new StringBuilder(); // StringTokenizer st = new StringTokenizer(str, ""); // while (st.hasMoreTokens()) { // StringBuilder thisToken = new StringBuilder(st.nextToken()); // result.append(thisToken.reverse()).append(" "); // } // return result.toString(); // } }

private static String reverse(String toReverse) { char[] sequence = toReverse.toCharArray(); char temp; int head = 0, tail = sequence.length - 1; while (head < tail) { temp = sequence[head]; sequence[head++] = sequence[tail]; sequence[tail--] = temp; } return new String(sequence); }

private static String reverse(String s) { char[] target = new char[s.length()]; for (int i = 0; i < s.length(); i++) target[target.length - i - 1] = s.charAt(i); return new String(target); }

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Gellert Varga

Poziom 23 , Szekesfehervar, Hungary

30 listopada 2021, 17:54

przydatny

I really like Lisa's solution that a single StringBuilder method solves the whole problem:) Unfortunately I didn't have this knowledge when I solved this task, so my solution is not so simple: I read it line by line (with readLine), and I dispieced the resulting string into a char array (with the toCharArray() String method). I then printed this using a loop, moving from the end of the char array to the index zero.

Lisa

Poziom 41

30 listopada 2021, 17:13

30 listopada 2021, 21:19

Oh, and if that's the case that you do not know about StringBuilders reverse method or you do not want to use it, then change line 15 in my code to

System.out.println(reverse(bufferedReader1.readLine()));

and add a reverse method eg.:

I'd go with the second. The first is cooool if you already have an array and want to return one.

Krateusz Majewski

Poziom 31 , Poland, Poland

1 grudnia 2021, 10:20

I tried using stringBuilder.append method within the while loop, but lines where misplaced and my result was: ogimA .ątsimargorp metseJ Thanks Lisa, your solution is really simple and there was StringBuilder.reverse subject earlier in the course, but I didn't figure it out to use it within the loop.