Merge branch 'master' of github.com:rasmus4200/algorithms101

rasmus4200 · Jan 31, 2020 · 13ac212 · 13ac212
2 parents aaf57e1 + d0584dc
commit 13ac212
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Showing 2 changed files with 16 additions and 15 deletions.
diff --git a/src/main/java/datastructures/HashTable.java b/src/main/java/datastructures/HashTable.java
@@ -53,36 +53,28 @@ public String get(String key) {
         // Get the current list of entries
         HashEntry entries = data[index];
 
-        // if we have existing entries against this key...
-        if (entries != null) {
-            // else walk chain until find a match
-            while (!entries.key.equals(key) && entries.next !=null) {
-                entries = entries.next;
-            }
-            // then return it
-            return entries.value;
+        // While there are elements in the linked list...
+        while (entries != null) {
+            if (entries.key.equals(key))    // Check for match
+                return entries.value;       // if match found return
+            entries = entries.next;         // else go to next node in chain
         }
 
-        // it we have no entries against this key...
-       return null;
+       return null;                         // return null if no match found
     }
 
     private int getIndex(String key) {
         // Get the hash code
         int hashCode = key.hashCode();
-        System.out.println("hashCode = " + hashCode);
 
         // Convert to index
         int index = (hashCode & 0x7fffffff) % INITIAL_SIZE;
-//        int index = hashCode % INITIAL_SIZE;
 
         // Hack to force collision for testing
-        if (key.equals("John Smith") || key.equals("Sandra Dee")) {
+        if (key.equals("John Smith") || key.equals("Sandra Dee") || key.equals("Tim Lee")) {
             index = 4;
         }
 
-        System.out.println("index = " + index);
-
         return index;
     }
 

diff --git a/src/test/java/datastructures/HashTableTest.java b/src/test/java/datastructures/HashTableTest.java
@@ -26,10 +26,18 @@ public void PutAndGet() {
         Assert.assertEquals("521-5030", hashTable.get("Sam Doe"));
         Assert.assertEquals("521-9655", hashTable.get("Sandra Dee"));
         Assert.assertEquals("418-4165", hashTable.get("Ted Baker"));
+        Assert.assertEquals(null, hashTable.get("Tim Lee"));
 
         hashTable.toString();
     }
 
+    @Test
+    public void Empty() {
+        Assert.assertEquals(null, hashTable.get("Ted Baker"));
+        Assert.assertEquals(null, hashTable.get("Tim Lee"));
+        hashTable.toString();
+    }
+
     @Test
     public void Collision() {
         // these keys will collide
@@ -38,5 +46,6 @@ public void Collision() {
 
         Assert.assertEquals("521-1234", hashTable.get("John Smith"));
         Assert.assertEquals("521-9655", hashTable.get("Sandra Dee"));
+        Assert.assertEquals(null, hashTable.get("Tim Lee"));
     }
 }