solves complete tree nodes in java

Author: anishLearnsToCode

README.md

@@ -178,7 +178,7 @@
 | 219  | [Contains Duplicate II](https://leetcode.com/problems/contains-duplicate-ii)                                                                              |                               [![Java](assets/java.png)](src/ContainsDuplicateII.java) [![Python](assets/python.png)](python/contains_duplicate_ii.py)                               |                                                                                                                                   |
 | 220  | [Contains Duplicate III](https://leetcode.com/problems/contains-duplicate-iii)                                                                            |                                                                                                                                                                                      |                                                                                                                                   |
 | 221  | [Maximal Square](https://leetcode.com/problems/maximal-square)                                                                                            |                                                                                                                                                                                      |                                                                                                                                   |
-| 222  | [Count Complete Tree Nodes](https://leetcode.com/problems/count-complete-tree-nodes)                                                                      |                                                                                                                                                                                      |                                                                                                                                   |
+| 222  | [Count Complete Tree Nodes](https://leetcode.com/problems/count-complete-tree-nodes)                                                                      |                                                             [![Java](assets/java.png)](src/CountCompleteTreeNodes.java)                                                              |                                                                                                                                   |
 | 223  | [Rectangle Area](https://leetcode.com/problems/rectangle-area)                                                                                            |                                                                                                                                                                                      |                                                                                                                                   |
 | 225  | [Implement Stack using Queues](https://leetcode.com/problems/implement-stack-using-queues)                                                                |                                 [![Java](assets/java.png)](src/MyStack.java) [![Python](assets/python.png)](python/implement_stack_using_queues.py)                                  |                                                                                                                                   |
 | 226  | [Invert Binary Tree](https://leetcode.com/problems/invert-binary-tree)                                                                                    |                                  [![Java](assets/java.png)](src/InvertBinaryTree.java) [![Python](assets/python.png)](python/invert_binary_tree.py)                                  |                                                                                                                                   |

src/CountCompleteTreeNodes.java

@@ -0,0 +1,19 @@
+// https://leetcode.com/problems/count-complete-tree-nodes
+// T: O(log(n) ^ 2)
+// S: O(log(n))
+
+public class CountCompleteTreeNodes {
+    private static int depth(TreeNode root) {
+        if (root == null) return 0;
+        return 1 + depth(root.left);
+    }
+
+    public static int countNodes(TreeNode root) {
+        if (root == null) return 0;
+        int leftDepth = depth(root.left);
+        int rightDepth = depth(root.right);
+        return 1 + (leftDepth == rightDepth
+                ? ((1 << leftDepth) - 1) + countNodes(root.right)
+                : countNodes(root.left) + countNodes(root.right));
+    }
+}

src/TreeNode.java

@@ -1,4 +1,4 @@
-public class TreeNode {
+public class TreeNode implements TreePrinter.PrintableNode {
     int val;
     TreeNode left;
     TreeNode right;
@@ -9,4 +9,19 @@ public class TreeNode {
         this.left = left;
         this.right = right;
     }
+
+    @Override
+    public TreePrinter.PrintableNode getLeft() {
+        return this.left;
+    }
+
+    @Override
+    public TreePrinter.PrintableNode getRight() {
+        return this.right;
+    }
+
+    @Override
+    public String getText() {
+        return this.val + "";
+    }
 }

src/TreePrinter.java

@@ -7,19 +7,15 @@
  *
  * @author saiteja
  */
-public class TreePrinter
-{
+public class TreePrinter {
     /** Node that can be printed */
-    public interface PrintableNode
-    {
+    public interface PrintableNode {
         /** Get left child */
         PrintableNode getLeft();
 
-
         /** Get right child */
         PrintableNode getRight();
 
-
         /** Get text to be printed */
         String getText();
     }
@@ -31,8 +27,7 @@ public interface PrintableNode
      * @param root
      *            tree root node
      */
-    public static void print(PrintableNode root)
-    {
+    public static void print(PrintableNode root) {
         List<List<String>> lines = new ArrayList<List<String>>();
 
         List<PrintableNode> level = new ArrayList<PrintableNode>();