problems: add „235. Lowest Common Ancestor of a Binary Search Tree“

Signed-off-by: Matej Focko <mfocko@redhat.com>

problems/lowest-common-ancestor-of-a-binary-search-tree.kt

@@ -0,0 +1,37 @@
+/**
+ * Definition for a binary tree node.
+ * class TreeNode(var `val`: Int = 0) {
+ *     var left: TreeNode? = null
+ *     var right: TreeNode? = null
+ * }
+ */
+
+class Solution {
+    fun lowestCommonAncestor(root: TreeNode?, p: TreeNode?, q: TreeNode?): TreeNode? {
+        var ancestor: TreeNode? = null
+        var pTrack = root
+        var qTrack = root
+
+        while (pTrack == qTrack && pTrack != null && qTrack != null) {
+            ancestor = pTrack
+
+            if (pTrack!!.`val` == p!!.`val`) {
+                return p
+            } else if (p!!.`val` < pTrack!!.`val`) {
+                pTrack = pTrack.left
+            } else {
+                pTrack = pTrack.right
+            }
+
+            if (qTrack!!.`val` == q!!.`val`) {
+                return q
+            } else if (q!!.`val` < qTrack!!.`val`) {
+                qTrack = qTrack.left
+            } else {
+                qTrack = qTrack.right
+            }
+        }
+
+        return ancestor
+    }
+}