Create 1609-even-odd-tree.kt

Author: a93a

kotlin/1609-even-odd-tree.kt

@@ -0,0 +1,28 @@
+class Solution {
+    fun isEvenOddTree(root: TreeNode?): Boolean {
+        val q = LinkedList<TreeNode?> ().apply { addLast(root) }
+        var even = true
+
+        while (q.isNotEmpty()) {
+            var prev = if (isEven) Integer.MIN_VALUE else Integer.MAX_VALUE
+
+            repeat (q.size) {
+                val node = q.removeFirst()!!
+
+                if (even && (node.`val` % 2 == 0 || node.`val` <= prev))
+                    return false
+                else if (!even && (node.`val` % 2 == 1 || node.`val` >= prev))
+                    return false
+
+                prev = node.`val`
+
+                node.left?.let { q.addLast(it) }
+                node.right?.let { q.addLast(it) }
+            }
+
+            even = !even
+        }
+
+        return true
+    }
+}