מריה בוטוסוב

יש לבנות עץ ממערך של מספרים

public class TreeNod{
    public int? val;
    public TreeNode left;   public TreeNode right;
    public TreeNode(int? x) { val = x; }
}
 
public static TreeNode toTreeNode(this int?[] tree) {
    if (tree.Length == 0) return null;
    TreeNode root = new TreeNode(tree[0]);
    Queue<TreeNode> q = new Queue<TreeNode>();
    q.Enqueue(root);
    for (int i = 1; i < tree.Length; i++) {
        TreeNode node = q.Peek();
        if (node.left == null) {
            node.left = new TreeNode(tree[i]);
           if (tree[i] != null) q.Enqueue(node.left);
        }
        else if (node.right == null) {
            node.right = new TreeNode(tree[i]);
            if (tree[i] != null) q.Enqueue(node.right);
            q.Dequeue();
        }
    }
    return root;
}
 
static void Main(string[] args) {
    int?[] arr = new int?[] {1, null, 0, 1 };
    TreeNode root = arr.toTreeNode();
}