Tukukkk

I wrote below code and i want to identify the test cases where my code fails.I recently participated in contest where my one test case is failed to pass out of 15 test cases, I have one more attempt left and I want to identify the possible test cases where my test case failed. so i will improvise the same, in addition I also want to enhance it, meaning,also suggest me the best practice to improve performance.

At last, In the below code I have one method returnFinalComplement(String reverseStr) which return the complement, for calculating complement I have two Approaches, both are doing the same job, I am currenlty using approach-1, but i want to know about approach-2, which approach can pass all the test cases .

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

import java.util.ArrayList;

import java.util.List;

import java.util.Objects;

import java.util.SortedSet;

import java.util.TreeSet;



/*

 * To change this license header, choose License Headers in Project Properties.

 * To change this template file, choose Tools | Templates

 * and open the template in the editor.

 */

/**

 *

 * @author Ossu

 */

class DNAString {



    private final static Character DATASET = {'A', 'C', 'G', 'T'};

    private final static int MIN_RANGE = 0;

    private final static int MAX_RANGE = 1000;

    private final static String INVALID_CHAR = "Invalid input,not matched with dataset";

    private final static String CHAR_LENGTH_EXCEEDS = "Input does not allow to be exceeds more than " + MAX_RANGE + " characters";



    private static String returnFinalComplement(String reverseStr) {

//APPROACH-1

        StringBuilder finalStr = new StringBuilder();

        for (char c : reverseStr.toCharArray()) {

            finalStr.append(

                    c == 'G' ? 'C'

                            : c == 'C' ? 'G'

                                    : c == 'T' ? 'A'

                                            : c == 'A' ? 'T'

                                                    : c

            );



        }

        return finalStr.toString();





//APPROACH-2





char charlist = list.toCharArray();

        for (int i = 0; i < charlist.length; i++) {

            switch (charlist[i]) {

                case 'A': {

                    charlist[i] = 'T';

                }

                break;

                case 'T': {

                    charlist[i] = 'A';

                }

                break;

                case 'G': {

                    charlist[i] = 'C';

                }

                break;

                case 'C': {

                    charlist[i] = 'G';

                }

                break;

            }

        }

        return new String(charlist);







    }





    public static boolean validateInput(String input) {

        List<Character> chars = new ArrayList<>();

        for (char c : input.toCharArray()) {

            chars.add(c);

        }

        boolean result = false;

        SortedSet<Character> mySet = new TreeSet<>(chars);

        for (int i = 0; i <= mySet.size();) {

            for (Character c : mySet) {

                result = Objects.equals(c, DATASET[i]);

                i++;

                if (!result) {

                    break;

                }

            }

            if (result) {

                return result;

            } else {

                break;

            }

        }

        return result;



    }



    public static String reverseIt(String source) {

        int i, len = source.length();

        StringBuilder dest = new StringBuilder(len);

        for (i = (len - 1); i >= 0; i--) {

            dest.append(source.charAt(i));

        }

        return dest.toString();

    }



    public static void main(String args) throws IOException {



        BufferedReader readInput = new BufferedReader(new InputStreamReader(System.in));

        String source = readInput.readLine();

        if (source.length() > MIN_RANGE && source.length() <= MAX_RANGE) {

            boolean validateInput = validateInput(source);

            if (validateInput) {

//                String reverseString = reverseIt(source);

                String reverseString = reverseIt(source);

                System.out.println(returnFinalComplement(reverseString));

//                String revereStringComplement = returnFinalComplement(reverseString);

            } else {

                System.out.println(INVALID_CHAR);

            }

        } else {

            System.out.println(CHAR_LENGTH_EXCEEDS);

        }

    }

}