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Author: piCOOL3

binarytree_create_binarytree_with_nullvaluesCS.cs

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+/*
+Given binary tree [3,9,20,null,null,15,7],
+
+    3
+   / \
+  9  20
+    /  \
+   15   7
+*/
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace binarytree_create_binarytree_with_nullvaluesCS
+{
+    public class TreeNode
+    {
+      public int val;
+      public TreeNode left;
+      public TreeNode right;
+      public TreeNode(int value ) { val = value; }
+    }
+    class Program
+    {
+        static TreeNode build_tree(char[] level_order_collection, int start_index, int end_index)
+        {
+            //  a tree is always built up in bottom-up structure 
+            TreeNode root = null;
+            // initial referance set to null 
+
+            if (start_index <= end_index)
+            {
+                // node to be created has not over-shooted the available range 
+
+                root = new TreeNode(level_order_collection[start_index]);
+
+                root.left = build_tree(level_order_collection, (2 * start_index) + 1, end_index);
+                root.right = build_tree(level_order_collection, (2 * start_index) + 2, end_index);
+                // recursively call the same tree build function to create left sub-tree and right sub tree 
+
+            }
+            return root;
+        }
+        static void Main(string[] args)
+        {
+            Nullable<int> level_order = new Nullable<int> { 3, 9, 20, null, null, 15, 7 };
+            //  level order traversal for the tree nodes provided 
+        }
+    }
+}