Print elements of a ternary tree

A full ternary tree with depth n is given. Write a program that prints all nodes of the tree in Pre-Order. Enumeration starts from 0 and goes sequentially through the levels.

Input: n is the depth of the tree.

Output: a sequence of nodes in Pre-Order divided by spaces.

Sample Input:
2

Sample Output:
0 1 4 5 6 2 7 8 9 3 10 11 12

class Main {
public static void main(String[] args) throws IOException {
    BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
    int targetDepth = Integer.parseInt(reader.readLine());
    int currentDepth = 1;
    int node = 0;
    System.out.print(node + " ");
    printNodes(node, currentDepth, targetDepth);
}

public static void printNodes(int node, int currentDepth, int targetDepth) {
    if (targetDepth == 1) {
        System.out.print((3 * node + 1) + " " + (3 * node + 2) + " " + (3 * node + 3));
        return;
    }
    if (currentDepth < targetDepth) {
        int leftChild, midChild, rightChild;
        int rightParent = 3 * node + 3;
        node++;
        while (node <= rightParent) {
            leftChild = 3 * node + 1;
            midChild = 3 * node + 2;
            rightChild = 3 * node + 3;
            System.out.print(node + " " + leftChild + " " + midChild + " " + rightChild + " ");
            node++;
        }
        node = rightParent;
        currentDepth++;
        printNodes(node, currentDepth, targetDepth);
    }
}

A simple test reports an error: Invalid answer. The test uses a tree with a depth of 3, although the test passes successfully with a tree depth of 2. I have already checked 100 times, based on the conditions of the problem, the answer must be correct. Perhaps I am missing something. Please point me in the right direction.

what u need to do is:

public static void process(Node n){
  sysout(n.value)
  process(n.right)
  process(n.mid)
  process(n.left)}

what you are doing is:

public static void process(Node n){
      sysout(n.value)
      sysout(n.left.value)
      sysout(n.mid.value)
      sysout(n.right.value)
      process(n.right)}

keep it simple, just try to print current node and then move on to its children.

If you are currently getting a course on data structures, there is also a method that uses stack or queue. I recommend checking on it too. While using recursion, you naturally use the process stack java uses.

pseudo code goes like:

push initial node into the stack 
while stack has nodes:
     pop node from the stack 
     print nodes value 
     if node is not at the target depth:
          push node's children onto the stack(from right to left)

when stack is empty, you got your sequence!