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import java.util.*;

public class NAryTreeTraversals {

    // Preorder Traversal
    public List<Integer> preorder(Node root) {
        List<Integer> result = new ArrayList<>();
        preorderHelper(root, result);
        return result;
    }

    private void preorderHelper(Node node, List<Integer> result) {
        if (node == null) return;
        result.add(node.val); // Process root
        for (Node child : node.children) { // Process children
            preorderHelper(child, result);
        }
    }
}