@@ -0,0 +1,45 @@
+package com.hellokoding.algorithm;
+
+public class AnagramsByBruteForce {
+    static boolean areAnagrams(String s, String t) {
+        if (s.length() != t.length()) {
+            return false;
+        }
+
+        return areAnagramsByBackTracking(0, s, t);
+    }
+
+    static boolean areAnagramsByBackTracking(int i, String s1, String s2) {
+        if (i == s1.length()-1) {
+            return s1.equals(s2);
+        }
+
+        for(int j=i; j<s1.length(); j++) {
+            s1 = swap(s1, i, j);
+
+            if (areAnagramsByBackTracking(i+1, s1, s2)) {
+                return true;
+            }
+
+            s1 = swap(s1, i, j); // backtracking
+        }
+
+        return false;
+    }
+
+    static String swap(String str, int i, int j) {
+        char[] arr = str.toCharArray();
+
+        char temp = arr[i];
+        arr[i] = arr[j];
+        arr[j] = temp;
+
+        return String.valueOf(arr);
+    }
+
+    public static void main(String[] args) {
+        System.out.println(areAnagrams("listen", "silent"));
+        System.out.println(areAnagrams("eleven plus two", "twelve plus one"));
+        System.out.println(areAnagrams("rat", "car"));
+    }
+}
@@ -0,0 +1,27 @@
+package com.hellokoding.algorithm;
+
+public class AnagramsByCounting {
+    static boolean areAnagrams(String s, String t) {
+        if (s.length() != t.length()) {
+            return false;
+        }
+
+        for (char ch = 'a'; ch <= 'z'; ch++) {
+            if (countOccurrences(ch, s) != countOccurrences(ch, t)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    static int countOccurrences(char c, String s) {
+        return s.length() - s.replace(String.valueOf(c), "").length();
+    }
+
+    public static void main(String[] args) {
+        System.out.println(areAnagrams("listen", "silent"));
+        System.out.println(areAnagrams("eleven plus two", "twelve plus one"));
+        System.out.println(areAnagrams("rat", "car"));
+    }
+}
@@ -0,0 +1,33 @@
+package com.hellokoding.algorithm;
+
+public class AnagramsByHistogramming {
+    static boolean areAnagrams(String s, String t) {
+        if (s.length() != t.length()) {
+            return false;
+        }
+
+        s = s.replaceAll("\\s", "");
+        t = t.replaceAll("\\s", "");
+
+        int[] frequencies = new int[26];
+
+        for (int i = 0; i < s.length(); i++) {
+            frequencies[s.charAt(i) - 'a']++;
+            frequencies[t.charAt(i) - 'a']--;
+        }
+
+        for (int count : frequencies) {
+            if (count != 0) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    public static void main(String[] args) {
+        System.out.println(areAnagrams("listen", "silent"));
+        System.out.println(areAnagrams("eleven plus two", "twelve plus one"));
+        System.out.println(areAnagrams("rat", "car"));
+    }
+}
@@ -0,0 +1,25 @@
+package com.hellokoding.algorithm;
+
+import java.util.Arrays;
+
+public class AnagramsBySorting {
+    static boolean areAnagrams(String s, String t) {
+        if (s.length() != t.length()) {
+            return false;
+        }
+
+        char[] a1 = s.toCharArray();
+        char[] a2 = t.toCharArray();
+
+        Arrays.sort(a1);
+        Arrays.sort(a2);
+
+        return Arrays.equals(a1, a2);
+    }
+
+    public static void main(String[] args) {
+        System.out.println(areAnagrams("listen", "silent"));
+        System.out.println(areAnagrams("eleven plus two", "twelve plus one"));
+        System.out.println(areAnagrams("rat", "car"));
+    }
+}