refactor: unified duplicate Anagram classes into a single implementation

Author: DenizAltunkapan

src/main/java/com/thealgorithms/strings/Anagrams.java

@@ -23,7 +23,9 @@ private Anagrams() {
      * @param t the second string
      * @return true if the strings are anagrams, false otherwise
      */
-    public static boolean approach1(String s, String t) {
+    public static boolean areAnagramsBySorting(String s, String t) {
+        s = s.toLowerCase().replaceAll("[^a-z]", "");
+        t = t.toLowerCase().replaceAll("[^a-z]", "");
         if (s.length() != t.length()) {
             return false;
         }
@@ -43,17 +45,18 @@ public static boolean approach1(String s, String t) {
      * @param t the second string
      * @return true if the strings are anagrams, false otherwise
      */
-    public static boolean approach2(String s, String t) {
-        if (s.length() != t.length()) {
-            return false;
+    public static boolean areAnagramsByCountingChars(String s, String t) {
+        s = s.toLowerCase().replaceAll("[^a-z]", "");
+        t = t.toLowerCase().replaceAll("[^a-z]", "");
+        int[] dict = new int[128];
+        for (char ch : s.toCharArray()) {
+            dict[ch]++;
         }
-        int[] charCount = new int[26];
-        for (int i = 0; i < s.length(); i++) {
-            charCount[s.charAt(i) - 'a']++;
-            charCount[t.charAt(i) - 'a']--;
+        for (char ch : t.toCharArray()) {
+            dict[ch]--;
         }
-        for (int count : charCount) {
-            if (count != 0) {
+        for (int e : dict) {
+            if (e != 0) {
                 return false;
             }
         }
@@ -70,7 +73,9 @@ public static boolean approach2(String s, String t) {
      * @param t the second string
      * @return true if the strings are anagrams, false otherwise
      */
-    public static boolean approach3(String s, String t) {
+    public static boolean areAnagramsByCountingCharsSingleArray(String s, String t) {
+        s = s.toLowerCase().replaceAll("[^a-z]", "");
+        t = t.toLowerCase().replaceAll("[^a-z]", "");
         if (s.length() != t.length()) {
             return false;
         }
@@ -96,7 +101,9 @@ public static boolean approach3(String s, String t) {
      * @param t the second string
      * @return true if the strings are anagrams, false otherwise
      */
-    public static boolean approach4(String s, String t) {
+    public static boolean areAnagramsUsingHashMap(String s, String t) {
+        s = s.toLowerCase().replaceAll("[^a-z]", "");
+        t = t.toLowerCase().replaceAll("[^a-z]", "");
         if (s.length() != t.length()) {
             return false;
         }
@@ -123,7 +130,9 @@ public static boolean approach4(String s, String t) {
      * @param t the second string
      * @return true if the strings are anagrams, false otherwise
      */
-    public static boolean approach5(String s, String t) {
+    public static boolean areAnagramsBySingleFreqArray(String s, String t) {
+        s = s.toLowerCase().replaceAll("[^a-z]", "");
+        t = t.toLowerCase().replaceAll("[^a-z]", "");
         if (s.length() != t.length()) {
             return false;
         }

src/main/java/com/thealgorithms/strings/CheckAnagrams.java

@@ -13,36 +13,37 @@ record AnagramTestCase(String input1, String input2, boolean expected) {
 
     private static Stream<AnagramTestCase> anagramTestData() {
         return Stream.of(new AnagramTestCase("late", "tale", true), new AnagramTestCase("late", "teal", true), new AnagramTestCase("listen", "silent", true), new AnagramTestCase("hello", "olelh", true), new AnagramTestCase("hello", "world", false), new AnagramTestCase("deal", "lead", true),
-            new AnagramTestCase("binary", "brainy", true), new AnagramTestCase("adobe", "abode", true), new AnagramTestCase("cat", "act", true), new AnagramTestCase("cat", "cut", false));
+            new AnagramTestCase("binary", "brainy", true), new AnagramTestCase("adobe", "abode", true), new AnagramTestCase("cat", "act", true), new AnagramTestCase("cat", "cut", false), new AnagramTestCase("Listen", "Silent", true), new AnagramTestCase("Dormitory", "DirtyRoom", true),
+            new AnagramTestCase("Schoolmaster", "TheClassroom", true), new AnagramTestCase("Astronomer", "MoonStarer", true), new AnagramTestCase("Conversation", "VoicesRantOn", true));
     }
 
     @ParameterizedTest
     @MethodSource("anagramTestData")
     void testApproach1(AnagramTestCase testCase) {
-        assertEquals(testCase.expected(), Anagrams.approach1(testCase.input1(), testCase.input2()));
+        assertEquals(testCase.expected(), Anagrams.areAnagramsBySorting(testCase.input1(), testCase.input2()));
     }
 
     @ParameterizedTest
     @MethodSource("anagramTestData")
     void testApproach2(AnagramTestCase testCase) {
-        assertEquals(testCase.expected(), Anagrams.approach2(testCase.input1(), testCase.input2()));
+        assertEquals(testCase.expected(), Anagrams.areAnagramsByCountingChars(testCase.input1(), testCase.input2()));
     }
 
     @ParameterizedTest
     @MethodSource("anagramTestData")
     void testApproach3(AnagramTestCase testCase) {
-        assertEquals(testCase.expected(), Anagrams.approach3(testCase.input1(), testCase.input2()));
+        assertEquals(testCase.expected(), Anagrams.areAnagramsByCountingCharsSingleArray(testCase.input1(), testCase.input2()));
     }
 
     @ParameterizedTest
     @MethodSource("anagramTestData")
     void testApproach4(AnagramTestCase testCase) {
-        assertEquals(testCase.expected(), Anagrams.approach4(testCase.input1(), testCase.input2()));
+        assertEquals(testCase.expected(), Anagrams.areAnagramsUsingHashMap(testCase.input1(), testCase.input2()));
     }
 
     @ParameterizedTest
     @MethodSource("anagramTestData")
     void testApproach5(AnagramTestCase testCase) {
-        assertEquals(testCase.expected(), Anagrams.approach5(testCase.input1(), testCase.input2()));
+        assertEquals(testCase.expected(), Anagrams.areAnagramsBySingleFreqArray(testCase.input1(), testCase.input2()));
     }
 }