98. Validate Binary Search Tree go solution

Author: dfad

go/98-Validate-Binary-Search-Tree.go

@@ -0,0 +1,19 @@
+func isValidBST(root *TreeNode) bool {
+	return isValid(root, nil, nil)
+}
+
+func isValid(root, min, max *TreeNode) bool {
+	if root == nil {
+		return true
+	}
+
+	if min != nil && root.Val <= min.Val {
+		return false
+	}
+
+	if max != nil && root.Val >= max.Val {
+		return false
+	}
+
+	return isValid(root.Left, min, root) && isValid(root.Right, root, max)
+}