Create 0958-check-completeness-of-a-binary-tree.kt

kotlin/0958-check-completeness-of-a-binary-tree.kt

@@ -0,0 +1,34 @@
+/**
+ * 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 isCompleteTree(root: TreeNode?): Boolean {
+
+ val q = LinkedList<TreeNode?>().apply{
+ this.addFirst(root)
+ }
+
+ while(q.isNotEmpty()) {
+ val node = q.removeLast()
+
+ if(node != null) {
+ q.addFirst(node.left)
+ q.addFirst(node.right)
+ } else {
+ while(q.isNotEmpty()) {
+ if(q.removeLast() != null)
+ return false
+ }
+ }
+ }
+
+ return true
+ }
+}