Initial Commit

java/anagram/src/main/java/Anagram.java

@@ -0,0 +1,71 @@
+import java.util.*;
+
+/**
+ * Anagram will give you anagram info about a word
+ */
+public class Anagram {
+  String word;
+  Map<Character, Integer> map;
+  
+  public Anagram(String w) {
+    this.word = w;
+    this.map = generateCharMap(this.word);
+  }
+
+  public List<String> match(List<String> matchWords) {
+    List<String> ret = new ArrayList<String>();
+    Map<Character, Integer> myWordMap = this.generateCharMap(this.word);
+    for(int i = 0; i < matchWords.size(); i++) {
+      // Must have the same number of characters
+      String tstWord = matchWords.get(i);
+      if(tstWord.length() != this.word.length()) {
+        continue;
+      } 
+    
+      if(this.isAnagram(tstWord)) {
+        ret.add(matchWords.get(i));
+      }
+    }
+    return ret;
+  }
+
+  private boolean isAnagram(String tst) {
+    Map<Character, Integer> tstMap = new HashMap<Character, Integer>(this.map);
+    boolean ret = true;
+    tst = tst.toLowerCase();
+    if(tst.equals(this.word.toLowerCase())) {
+      return false;
+    }
+    for(int i = 0; i < tst.toCharArray().length; i++) {
+      if(tstMap.containsKey(tst.toCharArray()[i])) {
+        int left = tstMap.get(tst.toCharArray()[i]);
+        if(left <= 0) {
+          ret = false;
+        } else {
+          left--;
+          tstMap.put(tst.toCharArray()[i], left);
+        }
+      } else {
+        ret = false;
+      }
+      if(!ret) {
+        // If ret ever hits false, we're done.
+        break;
+      }
+    }
+    return ret;
+  }
+
+  private Map<Character, Integer> generateCharMap(String wrd) {
+    Map<Character, Integer> wordMap = new HashMap<Character, Integer>();
+    for(int i = 0; i < this.word.toCharArray().length; i++) {
+      Character tst = this.word.toCharArray()[i];
+      tst = Character.toLowerCase(tst);
+      if(!wordMap.containsKey(tst)) {
+        wordMap.put(tst, 0);
+      }
+      wordMap.put(tst, wordMap.get(tst)+1);
+    }
+    return wordMap;
+  }
+}

java/anagram/src/test/java/AnagramTest.java

@@ -0,0 +1,77 @@
+import static org.hamcrest.CoreMatchers.*;
+import static org.junit.matchers.JUnitMatchers.*;
+import static org.junit.Assert.*;
+
+import java.util.*;
+import org.junit.*;
+
+public class AnagramTest {
+
+    @Test
+    public void testNoMatches() {
+        Anagram detector = new Anagram("diaper");
+        assertTrue(detector.match(Arrays.asList("hello", "world", "zombies", "pants")).isEmpty());
+    }
+
+    @Test
+    public void testSimpleAnagram() {
+        Anagram detector = new Anagram("ant");
+        List<String> anagram = detector.match(Arrays.asList("tan", "stand", "at"));
+        assertThat(anagram, hasItems("tan"));
+    }
+
+    @Test
+    public void testDetectMultipleAnagrams() {
+        Anagram detector = new Anagram("master");
+        List<String> anagrams = detector.match(Arrays.asList("stream", "pigeon", "maters"));
+        assertThat(anagrams, hasItems("maters", "stream"));
+    }
+
+    @Test
+    public void testDoesNotConfuseDifferentDuplicates() {
+        Anagram detector = new Anagram("galea");
+        List<String> anagrams = detector.match(Arrays.asList("eagle"));
+        assertTrue(anagrams.isEmpty());
+    }
+
+    @Test
+    public void testIdenticalWordIsNotAnagram() {
+        Anagram detector = new Anagram("corn");
+        List<String> anagrams = detector.match(Arrays.asList("corn", "dark", "Corn", "rank", "CORN", "cron", "park"));
+        assertEquals(anagrams, Arrays.asList("cron"));
+    }
+
+    @Test
+    public void testEliminateAnagramsWithSameChecksum() {
+        Anagram detector = new Anagram("mass");
+        assertTrue(detector.match(Arrays.asList("last")).isEmpty());
+    }
+
+    @Test
+    public void testEliminateAnagramSubsets() {
+        Anagram detector = new Anagram("good");
+        assertTrue(detector.match(Arrays.asList("dog", "goody")).isEmpty());
+    }
+
+    @Test
+    public void testDetectAnagrams() {
+        Anagram detector = new Anagram("listen");
+        List<String> anagrams = detector.match(Arrays.asList("enlists", "google", "inlets", "banana"));
+        assertThat(anagrams, hasItems("inlets"));
+    }
+
+    @Test
+    public void testMultipleAnagrams() {
+        Anagram detector = new Anagram("allergy");
+        List<String> anagrams = detector.match(Arrays.asList("gallery", "ballerina", "regally", "clergy", "largely", "leading"));
+        assertThat(anagrams, hasItems("gallery", "largely", "regally"));
+    }
+
+    @Test
+    public void testAnagramsAreCaseInsensitive() {
+        Anagram detector = new Anagram("Orchestra");
+        List<String> anagrams = detector.match(Arrays.asList("cashregister", "Carthorse", "radishes"));
+        assertThat(anagrams, hasItems("Carthorse"));
+    }
+
+}