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copied!<p>I assume this is homework, so I will give some pointers instead of some code.</p> <ul> <li>your trace method does a recursive descent, therefore the stack is not needed - you can build the path structure while returning from a found node</li> <li>if your method uses a boolean or List return value , you can print the path while returning, or build up a list with the Nodes to print after the search method returns</li> </ul> <p><strong>Edit</strong>: If the path node to root is wanted, a simple boolean return suffices:</p> <pre><code>private boolean trace(Node parent, Node node) { boolean found = (node.data == parent.data) if (!found && parent.left != null) { found = trace(parent.left, node); } if (!found && parent.right != null){ found = trace(parent.right, node); } if (found) { System.out.println(parent.data); } return found; } </code></pre> <p>If you need the path from root to node, you can pass a List to receive the nodes in order:</p> <pre><code>private boolean trace(Node parent, Node node, List path) { boolean found = (node.data == parent.data) if (!found && parent.left != null) { found = trace(parent.left, node); } if (!found && parent.right != null){ found = trace(parent.right, node); } if (found) { path.add(0, parent); } return found; } </code></pre> <p>alternatively you can build the path on your way back and return as a list.</p> <pre><code>private List trace(Node parent, Node node) { List path = null; if (null != node) { if (node.data == parent.data) { path = new ArrayList(); } else { path = trace(parent.left, node); if (null == path) { path = trace(parent.right, node); } } if (null != path) { path.add(0, parent); } } return path; } </code></pre>

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