kt: keep ‹TreeNode› only once

Signed-off-by: Matej Focko <me@mfocko.xyz>

kt/TreeNode.kt

@@ -0,0 +1,4 @@
+class TreeNode(var `val`: Int) {
+    var left: TreeNode? = null
+    var right: TreeNode? = null
+}

kt/binary-tree-inorder-traversal.kt

@@ -1,13 +1,3 @@
-/**
- * Example:
- * var ti = TreeNode(5)
- * var v = ti.`val`
- * Definition for a binary tree node.
- * class TreeNode(var `val`: Int) {
- *     var left: TreeNode? = null
- *     var right: TreeNode? = null
- * }
- */
 class Solution {
     fun inorderTraversal(
         root: TreeNode?,

kt/binary-tree-level-order-traversal.kt

@@ -1,13 +1,3 @@
-/**
- * Example:
- * var ti = TreeNode(5)
- * var v = ti.`val`
- * Definition for a binary tree node.
- * class TreeNode(var `val`: Int) {
- *     var left: TreeNode? = null
- *     var right: TreeNode? = null
- * }
- */
 class Solution {
     private fun levelOrder(
         root: TreeNode?,

kt/construct-string-from-binary-tree.kt

@@ -1,13 +1,3 @@
-/**
- * Example:
- * var ti = TreeNode(5)
- * var v = ti.`val`
- * Definition for a binary tree node.
- * class TreeNode(var `val`: Int) {
- *     var left: TreeNode? = null
- *     var right: TreeNode? = null
- * }
- */
 class Solution {
     fun tree2str(root: TreeNode?): String {
         if (root == null) {

kt/delete-leaves-with-a-given-value.kt

@@ -1,8 +1,3 @@
-class TreeNode(var `val`: Int) {
-    var left: TreeNode? = null
-    var right: TreeNode? = null
-}
-
 class Solution {
     fun isLeaf(node: TreeNode?): Boolean {
         return node != null && node.left == null && node.right == null

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

@@ -1,11 +1,3 @@
-/**
- * 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?,

kt/validate-binary-search-tree.kt

@@ -1,13 +1,3 @@
-/**
- * Example:
- * var ti = TreeNode(5)
- * var v = ti.`val`
- * Definition for a binary tree node.
- * class TreeNode(var `val`: Int) {
- *     var left: TreeNode? = null
- *     var right: TreeNode? = null
- * }
- */
 class Solution {
     private data class SpecialRange(val min: Int? = null, val max: Int? = null) {
         fun check(x: Int): Boolean = (min == null || x > min) && (max == null || x < max)