653. Two Sum IV - Input is a BST

Author: a-khakimov

leetcode-scala/src/main/scala/LeetCode75/BinarySearchTree/653. Two Sum IV - Input is a BST.sc

@@ -0,0 +1,43 @@
+import scala.annotation.tailrec
+
+class TreeNode(_value: Int = 0, _left: TreeNode = null, _right: TreeNode = null) {
+  var value: Int = _value
+  var left: TreeNode = _left
+  var right: TreeNode = _right
+}
+
+object Solution {
+  def searchBST(root: TreeNode, node: TreeNode, value: Int): Boolean = {
+    if (root == null || root.value == node.value) false
+    else if (root.value == value) true
+    else {
+      if (value < root.value) searchBST(root.left, node, value)
+      else searchBST(root.right, node, value)
+    }
+  }
+
+  def findTarget(root: TreeNode, k: Int): Boolean = {
+    def search(node: TreeNode): Boolean = {
+      if (node == null) false else {
+        val w = k - node.value
+        val found = searchBST(root, node, w)
+        if (!found) {
+          val foundRight = search(node.right)
+          if (!foundRight) search(node.left)
+          else foundRight
+        } else found
+      }
+    }
+    search(root)
+  }
+}
+
+val tree1 = new TreeNode(4,
+  _left = new TreeNode(2,
+    _left = new TreeNode(1),
+    _right = new TreeNode(3),
+  ),
+  _right = new TreeNode(7),
+)
+
+Solution.findTarget(tree1, 10)