tree diameter

src/com/dsa/trees/LevelOrderTraversal.java

@@ -76,6 +76,22 @@ public class LevelOrderTraversal {
         return res;
     }
 
+    private static int diameter = 0;
+    public static int diameterOfBinaryTree(TreeNode root) {
+        diameter = 0;
+        if (root == null) return 0;
+        heightOfBT(root);
+        return diameter - 1;
+    }
+
+    public static int heightOfBT(TreeNode root) {
+        if (root == null) return 0;
+        int leftHeight = heightOfBT(root.left);
+        int rightHeight = heightOfBT(root.right);
+        diameter = Math.max(leftHeight + rightHeight + 1, diameter);
+        return Math.max(leftHeight, rightHeight) + 1;
+    }
+
     public static int minDepth(TreeNode root) {
         if(root == null) return 0;
         int leftHeight = minDepth(root.left);