Merge pull request wangzheng0822#405 from damianzhenxiaozhi/patch-3

removing all e in bucket, "use" should decrease

Author: wangzheng0822

java/18_hashtable/HashTable.java

@@ -142,12 +142,14 @@ public void remove(K key) {
  }
 
  Entry pre;
+ Entry<K, V> headNode = table[index];
  do {
  pre = e;
  e = e.next;
  if (key == e.key) {
  pre.next = e.next;
  size--;
+ if (headNode.next == null) use--;
  return;
  }
  } while (e.next != null);