Elerphore · December 30, 2022 20:50 · Dec 30, 2022
diff --git a/Bts.kt b/Bts.kt
@@ -0,0 +1,64 @@
+data class TreeNode(val value: Int, var left: TreeNode? = null, var right: TreeNode? = null)
+
+fun main() {
+    val root: TreeNode = initBSTree()
+    val isBST: Boolean = isBST(root, Int.MIN_VALUE, Int.MAX_VALUE)
+
+    println(isBST)
+}
+
+
+fun isBST(root: TreeNode?, min: Int, max: Int): Boolean {
+    if(root == null) return true;
+
+    return (root.value >= min &&
+            root.value < max &&
+            isBST(root.left, min, root.value) &&
+            isBST(root.right, root.value, max));
+}
+
+fun initBSTree(): TreeNode {
+    val rootNode = TreeNode(40)
+    val node20 = TreeNode(20)
+    val node10 = TreeNode(10)
+    val node30 = TreeNode(30)
+    val node60 = TreeNode(60)
+    val node50 = TreeNode(50)
+    val node70 = TreeNode(70)
+    val node5 = TreeNode(5)
+    val node55 = TreeNode(55)
+
+    rootNode.left = node20
+    rootNode.right = node60
+
+    node20.left = node10
+    node20.right = node30
+
+    node60.left = node50
+    node60.right = node70
+
+    node10.left = node5
+    node50.right = node55
+    return rootNode
+}
+
+fun createBinaryTree(): TreeNode {
+    val rootNode = TreeNode(40)
+    val node20 = TreeNode(20)
+    val node10 = TreeNode(10)
+    val node30 = TreeNode(30)
+    val node60 = TreeNode(60)
+    val node50 = TreeNode(50)
+    val node70 = TreeNode(70)
+    val node5 = TreeNode(5)
+    val node55 = TreeNode(55)
+    rootNode.left = node20
+    rootNode.right = node10
+    node20.left = node60
+    node20.right = node30
+    node60.left = node50
+    node60.right = node70
+    node10.left = node5
+    node50.right = node55
+    return rootNode
+}