Merge pull request neetcode-gh#983 from t3chkid/main

Replace recursive implementation with iterative implantation for 235. Lowest Common Ancestor of a Binary Search Tree in Kotlin

kotlin/235-Lowest-Common-Ancestor-Of-Binary-Search-Tree.kt

@@ -1,21 +1,22 @@
-/**
- * Definition for a binary tree node.
- * class TreeNode(var `val`: Int = 0) {
- * var left: TreeNode? = null
- * var right: TreeNode? = null
- * }
- */
+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? {
- if (p!!.`val` > root!!.`val` && q!!.`val` > root!!.`val`) {
- return lowestCommonAncestor(root.right, p, q)
+ fun lowestCommonAncestor(root: TreeNode, p: TreeNode?, q: TreeNode?): TreeNode? {
+ var currentRoot: TreeNode? = root
+ var lowestCommonAncestor: TreeNode? = null
+ while (currentRoot != null) {
+ if (currentRoot.`val` > p!!.`val` && currentRoot.`val` > q!!.`val`) {
+ currentRoot = currentRoot.left
+ } else if (currentRoot.`val` < p.`val` && currentRoot.`val` < q!!.`val`) {
+ currentRoot = currentRoot.right
+ } else {
+ lowestCommonAncestor = currentRoot
+ break
+ }
  }
-
- if (p!!.`val` < root!!.`val` && q!!.`val` < root!!.`val`) {
- return lowestCommonAncestor(root.left, p, q)
- }
-
- return root
+ return lowestCommonAncestor
  }
 }