Add Validate Tree

1 files changed, 24 insertions, 0 deletions

diff --git a/ValidateTree.java b/ValidateTree.java
new file mode 100644
index 0000000..6d65d80
--- /dev/null
+++ b/ValidateTree.java
@@ -0,0 +1,24 @@
+import java.lang.*;
+import java.util.*;
+import node.*;
+
+class ValidateTree {
+	public static boolean isValidBST(TreeNode root) {
+		if (root.left == null || root.right == null)
+			return true;
+		else if (root.left.val > root.val || root.right.val < root.val)
+			return false;
+		boolean l = isValidBST(root.left);
+		boolean r = isValidBST(root.right);
+		return l && r ? true : false;
+	}
+
+	public static void main(String[] args) {
+		TreeNode leftLeaf = new TreeNode(1);
+		TreeNode middleLeaf = new TreeNode(3);
+		TreeNode rightLeaf = new TreeNode(6);
+		TreeNode rightParent = new TreeNode(4);
+		TreeNode root = new TreeNode(5, leftLeaf, rightParent);
+		System.out.println(isValidBST(root));
+	}
+}