Create week 3 110. Balanced Binary Tree

Author: andysli6590

week 3 110. Balanced Binary Tree

@@ -0,0 +1,37 @@
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+public class Solution {
+    public boolean isBalanced(TreeNode root) {
+		if (root == null)
+			return true;
+ 
+		if (getHeight(root) == -1)
+			return false;
+ 
+		return true;
+	}
+  public int getHeight(TreeNode root) {
+		if (root == null)
+			return 0;
+ 
+		int left = getHeight(root.left);
+		int right = getHeight(root.right);
+ 
+		if (left == -1 || right == -1)
+			return -1;
+ 
+		if (Math.abs(left - right) > 1) {
+			return -1;
+		}
+ 
+		return Math.max(left, right) + 1;
+ 
+	}
+}