2471

Author: theforestvn88

2401-2500/2471_minimum_number_of_operations_to_sort_a_binary_tree_by_level.rb

@@ -0,0 +1,34 @@
+# Definition for a binary tree node.
+# class TreeNode
+#     attr_accessor :val, :left, :right
+#     def initialize(val = 0, left = nil, right = nil)
+#         @val = val
+#         @left = left
+#         @right = right
+#     end
+# end
+# @param {TreeNode} root
+# @return {Integer}
+def minimum_operations(root)
+    count = 0
+    queue = [root]
+    until queue.empty?
+        sorted_index = queue.map.with_index { |node, i| [node.val, i] }.sort_by(&:first).map(&:last)
+
+        (0...sorted_index.size).each { |i|
+            while (j = sorted_index[i]) != i
+                count += 1
+                sorted_index[i], sorted_index[j] = sorted_index[j], sorted_index[i]
+            end
+        }
+
+        next_queue = []
+        queue.each { |node|
+            next_queue << node.left if node.left
+            next_queue << node.right if node.right
+        }
+        queue = next_queue
+    end
+
+    count
+end