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| 1 | +package easy; |
| 2 | + |
| 3 | +/** |
| 4 | + * Have the function PalindromeCreator(str) take the str parameter being passed |
| 5 | + * and determine if it is possible to create a palindromic string |
| 6 | + * of minimum length 3 characters by removing 1 or 2 characters. |
| 7 | + * --- |
| 8 | + * For example: if str is "abjchba" then you can remove the characters jc to produce "abhba" |
| 9 | + * which is a palindrome. For this example your program should return the two characters |
| 10 | + * that were removed with no delimiter and in the order they appear in the string, so jc. |
| 11 | + * --- |
| 12 | + * If 1 or 2 characters cannot be removed to produce a palindrome, |
| 13 | + * then return the string not possible. If the input string is already a palindrome, |
| 14 | + * your program should return the string palindrome. |
| 15 | + * --- |
| 16 | + * The input will only contain lowercase alphabetic characters. |
| 17 | + * Your program should always attempt to create the longest palindromic substring |
| 18 | + * by removing 1 or 2 characters (see second sample test case as an example). |
| 19 | + * The 2 characters you remove do not have to be adjacent in the string. |
| 20 | + */ |
| 21 | +public class PalindromeCreator { |
| 22 | + |
| 23 | + /** |
| 24 | + * A support function checking if a given string is a palindrome. |
| 25 | + * |
| 26 | + * @param str input string |
| 27 | + * @return true if the string is a palindrome |
| 28 | + */ |
| 29 | + private static boolean isPalindrome(String str) { |
| 30 | + char[] strArr = str.toCharArray(); |
| 31 | + int len = strArr.length; |
| 32 | + for (int i = 0; i < len / 2; i++) { |
| 33 | + if (strArr[i] != strArr[len - i - 1]) { |
| 34 | + return false; |
| 35 | + } |
| 36 | + } |
| 37 | + return true; |
| 38 | + } |
| 39 | + |
| 40 | + /** |
| 41 | + * Palindrome Creator function. |
| 42 | + * |
| 43 | + * @param str input string |
| 44 | + * @return characters to be removed or "palindrome" or "not possible" |
| 45 | + */ |
| 46 | + private static String palindromeCreator(String str) { |
| 47 | + if (isPalindrome(str)) { |
| 48 | + return "palindrome"; |
| 49 | + } |
| 50 | + |
| 51 | + for (int i = 0; i < str.length(); i++) { |
| 52 | + StringBuilder combo = new StringBuilder(); |
| 53 | + for (int k = 0; k < str.length(); k++) { |
| 54 | + if (k != i) { |
| 55 | + combo.append(str.charAt(k)); |
| 56 | + } |
| 57 | + } |
| 58 | + if (isPalindrome(combo.toString()) && combo.length() >= 3) { |
| 59 | + return String.valueOf(str.charAt(i)); |
| 60 | + } |
| 61 | + } |
| 62 | + |
| 63 | + for (int i = 0; i < str.length(); i++) { |
| 64 | + for (int j = i; j < str.length(); j++) { |
| 65 | + StringBuilder combo = new StringBuilder(); |
| 66 | + for (int k = 0; k < str.length(); k++) { |
| 67 | + if (k != i && k != j) { |
| 68 | + combo.append(str.charAt(k)); |
| 69 | + } |
| 70 | + } |
| 71 | + if (isPalindrome(combo.toString()) && combo.length() >= 3) { |
| 72 | + return String.valueOf(str.charAt(i)) + str.charAt(j); |
| 73 | + } |
| 74 | + } |
| 75 | + } |
| 76 | + |
| 77 | + return "not possible"; |
| 78 | + } |
| 79 | + |
| 80 | + /** |
| 81 | + * Entry point. |
| 82 | + * |
| 83 | + * @param args command line arguments |
| 84 | + */ |
| 85 | + public static void main(String[] args) { |
| 86 | + var result2 = palindromeCreator("racecar"); |
| 87 | + System.out.println(result2); |
| 88 | + var result1 = palindromeCreator("vhhgghhgghhk"); |
| 89 | + System.out.println(result1); |
| 90 | + var result3 = palindromeCreator("rats live on no evil stars"); |
| 91 | + System.out.println(result3); |
| 92 | + } |
| 93 | + |
| 94 | +} |
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